Environmental Statement November 2010
Standard Information Sheet Project name DECC reference number Type of project Undertaker name Undertaker address Licences/owners
Quad204 Project D/4098/2010 Field re-development with additional wells and flowlines tiedin to a new FPSO BP Exploration Operating Company Ltd 1-4 Wellheads Avenue, Dyce, Aberdeen, AB21 7PB BP Exploration Operating Company Limited is the nominated operator Schiehallion field interests BP Exploration Operating Company Limited
33.35%
Shell U.K. Limited
33.35%
Hess Limited
15.67%
Statoil (U.K.) Limited
5.88%
OMV (U.K.) Limited
5.88%
Murphy Petroleum Limited
5.88%
Loyal field interests
Short description
Anticipated date for commencement of works Date and reference of any earlier environmental statements Significant environmental impacts identified Statement prepared by
November 2010
BP Exploration Operating Company Limited
50%
Shell U.K. Limited
50%
The project is located in UKCS Blocks 204 and 205, approximately 130 km west of Shetland. It will involve the redevelopment of the existing Schiehallion and Loyal fields. This includes new surface production facilities with the replacement of the existing Schiehallion Floating Production, Storage and Offloading (FPSO) vessel with a new FPSO, new production and water injection wells and additional subsea infrastructure to access the remaining hydrocarbon resources in the Schiehallion and Loyal reservoirs. First oil is targeted for fourth quarter of 2015 Schiehallion Development: Wider Field Perspective Environmental Statement D/2176/2004 None BP Exploration Operating Company Ltd
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November 2010
Non-Technical Summary
Non-Technical Summary Introduction This Environmental Statement (ES) presents the findings of the environmental impact assessment (EIA) conducted by BP for the proposed Quad204 Project. The project involves the redevelopment of the existing Schiehallion and Loyal fields. This includes new surface production facilities with the replacement of the existing Schiehallion Floating Production Storage and Offloading (FPSO) vessel with a new FPSO, additional new production and water injection wells and additional new subsea infrastructure.
The Schiehallion and Loyal fields lie within Quadrants 204 and 205 of the United Kingdom Continental Shelf (UKCS) approximately 130 km west of Shetland and 35 km east of the Faroe-UK median line, in water depths of 350 – 500 m on the slope of the Faroe-Shetland channel (Figure S.1).
Project background and purpose The Schiehallion field was discovered in late 1993 and the Loyal field was subsequently discovered in 1994. Both fields have historically been developed using subsea wells tied back to the Schiehallion FPSO. Since discovery, the Schiehallion field has been through a number of key phases of development
Figure S.1: Location of the proposed Quad204 Project
November 2010
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Non-Technical Summary summarised in Table S.1. Since first oil in 1998, the Schiehallion and Loyal fields have produced approximately 55.6 million cubic metres (ca. 350 million barrels) of oil and 4.6 billion standard cubic metres (ca. 163 billion standard cubic feet) of gas (to the end of 2009). Production history, seismic survey data and recent reservoir studies have confirmed that significant oil potential still remains to be extracted from the Schiehallion and Loyal fields. The existing Schiehallion/Loyal field development comprises five drill centres with a total well stock of 54 wells, extensive subsea infrastructure, the Schiehallion FPSO and a gas export pipeline to the Sullom Voe Terminal (SVT) in Shetland. Oil is exported via shuttle tanker to SVT. Several factors highlighted the opportunity to redevelop the Schiehallion and Loyal fields and the decision was therefore made by BP and its field partners to investigate the options available, known as the Quad204 Project.
Development concept and schedule A number of development concenpts were evaluated which fell into three broad categories: Development phase
Number of wells sanctioned
Phase 1
23 wells
h Continue with the existing FPSO with minimal modifications undertaken offshore h Bring the existing FPSO ashore to be refurbished h Replace the existing FPSO with a new build facility Based on analysis of the different options the selected development concept for the Quad204 Project was a new internal turret-moored FPSO at the same location as the existing Schiehallion FPSO. Gas will contine to be exported to SVT via the existing West of Shetland Pipeline System (WOSPS) and oil will be exported to an onshore terminal or direct to market in Northern Europe. The new FPSO will have increased capacity to enable optimum reservoir recovery and extend field life and also allow for any future expansion. A number of oil and gas discoveries and exploration prospects exist in the area which could potentially be developed in the future by subsea tie-back to the Quad204 infrastructure. It should be noted that any further field developments will be addressed via addenda to this environmental statement and subject to Type
Timeline
12 producer wells
Drilled 1996-2000 Brought online 1998-1999 (19 wells only)
10 water injector wells 1 gas disposal well Phase 2a
3 wells
1 producer well
Drilled 2000-2001
1 water injector well
Brought online 2000-2001
1 appraisal well Phase 2b
Phase 3
3 wells
8 wells
1 producer well
Drilled 2001-2002
2 water injector wells
Brought online 2001-2002 (1 producer well and 1 water injector well only)
3 producer wells
Drilled 2002-2003
4 water injector wells
Brought online 2002-2003
1 pilot hole Phase 4
5 wells
Proposed dedicated drill centre for the Claw area of the Schiehallion field with 5 wells tied back to the Schiehallion FPSO 2 producer wells 3 water injector wells
Phase 5
5 wells
Drilled 2003 (1 producer well and 1 water injector well only) Proposals later abandoned due to gas handling constraints on the Schiehallion FPSO
North West Area Development (NWAD)
Drilled 2006
1 multi-lateral producer well
Brought online 2009
2 water injector wells
Table S.1: Key development phases of the Schiehallion field
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November 2010
Non-Technical Summary approval from the Department of Energy and Climate Change (DECC). The current planned schedule for the Quad204 Project is for the project sanction decision to be made in the first quarter (Q1) of 2011. New subsea infrastructure will be installed in 2013 and drilling of new wells will commence in 2014. Following removal of the existing FPSO in Q3 of 2014 and the new FPSO to be on-station in Q1 of 2015, first oil is expected in Q4 2015. The timing of activities may change during project development.
Environmental statement remit This ES has been prepared in accordance with the requirements of the Offshore Petroleum Production and Pipelines (Assessment of Environmental Effects Regulations 1999 (as amended) which require evaluation of projects likely to have a significant effect on the offshore environment. The Quad204 Project, as a continued development of the existing Schiehallion/Loyal field development, is expected to see increases in production that would exceed the threshold levels set out in these regulations; therefore an EIA is a mandatory requirement. The aim of the EIA is to assess the potential environmental impacts that may arise from the proposed Quad204 Project and to identify measures that will be put in place during design and operations to prevent or minimise these impacts. The ES summarises the EIA process and outcomes. The scope of the EIA was developed and agreed during a scoping consultation process. Based on DECC guidance the proposed project as assessed within this ES comprises: h Installation and commissioning of the new FPSO and new subsea infrastructure h Continued production of the Schiehallion and Loyal fields through the new FPSO including fluids processing and export h Drilling of new wells via mobile drilling rigs h Decommissioning of the new FPSO and new subsea infrastructure Based on DECC guidance this ES does not include the disconnection of the existing FPSO (including temporary suspension of well and production operations) or tow away and sale or disposal of the existing FPSO. These activities will be addressed through BP’s environmental policy and management processes as appropriate. Other project elements not within the scope of this November 2010
ES are: h Existing well, subsea and pipeline infrastructure h Any potential future modifications at SVT that may be required as a result of receiving, storing and exporting fluids from the new FPSO h Fabrication of the new FPSO and new subsea infrastructure
Environmental philosophy BP and its field partners are committed to conducting activities in compliance with all applicable legislation and in a manner which contributes to BP’s stated goals of “no accidents, no harm to people and no damage to the environment”. In order to achieve these goals there is a hierarchy of common policies, commitments and expectations that identify policy and regulatory requirements and provide tools to assist in compliance and performance improvements. During operations, the Quad204 development will conform to the requirements of the Environmental Management System (EMS) established for the BP North Sea Strategic Performance Unit (SPU) which is certified to ISO 14001.
Assessment of alternatives Throughout concept selection, during initial engineering and going forward into detailed design the project is utilising a holistic process of option analysis in order to facilitate and document decisions in a transparent and objective way utilising criteria such as health and safety, environmental impact, cost and value, strategic benefit, field life operability, technical feasibility and deliverability. This holistic approach ensures environmental considerations are on an equal footing with other factors. A major focus throughout the decision-making process has been the incorporation of lessons learned and opportunities for improvement from the existing Schiehallion FPSO to the design of the new Quad204 FPSO. Major efforts have been made to remove or reduce environmental impact by design. During the concept selection process a comparative environmental assessment and Best Available Techniques (BAT) assessment was undertaken of the different options. The environmental screening focused on the risks and opportunities of each option and the results were fed into the overall concept selection process. Page v
Non-Technical Summary Following the selection of the development concept as a new build FPSO, a number of other engineering design options were identified as part of the concept definition process. The options also underwent a holistic option analysis process and those with environmental implications were grouped into six areas: subsea infrastructure, FPSO hull design and station keeping, oil and gas export, liquid effluent handling, gas handling and flare, and power generation. Various options were considered in each of these areas with decisions being made that removed or significantly reduced activities likely to have significant impacts on the environment e.g. improved produced water reinjection availability and a full flare gas recovery system. Some decisions are still to be made such as the use of multilateral well technology and the final drilling rig selection and these will be evaluated during detailed well planning. However, for all new wells it is anticipated that the project will use a conventionally moored 4th generation (or higher) semi–submersible drilling rig.
Wells will be directionally drilled to intercept the target reservoir rock in the optimum orientation taking into account the limitations imposed by the existing drill centre locations. A standard West of Shetland four-string (casing section) well design is assumed for the Quad204 Project wells. The wells will be drilled in a series of sections of decreasing diameter. The wells will have hole diameters of 36”, 26”, 17½”, 12¼" and 8½". In addition to new well construction, workovers and interventions will be carried out to maintain and repair the existing well stock where necessary. Drilling muds and cuttings handling Drilling muds have a number of functions depending on the geological formations being drilled and on the specific characteristics of the drilling fluid.
Reservoir and fluid characteristics
Drilling muds generally consist of a weighting agent such as barite suspended in water (known as water based muds or WBM) or some type of low toxicity mineral oil (known as oil based mud or OBM). Other chemicals may be added for specific functions depending on the geological formations being drilled and the viscosity and specific characteristics required of the drilling fluid.
Fluids and conditions at the Schiehallion and Loyal fields are relatively favourable, i.e. the oils are not at a high temperature or pressure; they are classed as medium crudes and contain a relatively low proportion of volatile components.
Different types of mud are used for different parts of the well and the final fluid selection for each section will be based on the technical requirements for each type of well (producer or injector).
Wells and drilling
The surface, upper and middle sections of each well will be drilled using WBM. OBM will be used for drilling the lower section and into the reservoir formation itself.
The development
The current well stock totals 54 wells. The project anticipates that up to 49 (estimated) additional new subsea production and water injection wells may be required at Schiehallion and Loyal, drilled at the five existing drill centre locations and in a number of phases: h Phase 1, the base case for the Quad204 Project (and the basis for this EIA), consists of an additional 25 infill wells (17 producers and 8 water injectors). The wells will be sanctioned on a well-by-well basis dependant upon prevailing economic conditions and drilled between 2014 and 2021 using one or two mobile drilling rigs h Phases 2 and 3 (long term) include the potential for an additional 24 infill wells (23 on Schiehallion and 1 on Loyal). These wells will be sanctioned on a well-by-well basis dependant upon prevailing economic conditions Page vi
WBM cuttings from the tophole section will be discharged to the seabed. A riser (pipe) will then be installed which connects the well to the drilling rig and all other cuttings can be circulated back up to the drilling rig. Drill cuttings with WBM from the middle section will be discharged from the rig into the sea following cuttings cleaning and mud recovery operations. Drill cuttings with OBM from the lower section will be contained on the rig and shipped to shore for treatment and disposal. Well control equipment and well testing The primary well control barrier is the use of weighted drilling fluids which are sufficiently heavy to counterbalance the formation pressure. The secondary barrier will be the blow out preventer (BOP) system which exists to prevent uncontrolled flow from the well by positively November 2010
Non-Technical Summary closing the well-bore when required. Testing of the wells will be necessary for effective reservoir management and assessment of reservoir performance. Production from the well will be routed to a test separator on the FPSO where metering equipment will monitor the well’s performance. The fluids will then pass into the main process system and no flaring will be required.
Subsea infrastructure The Quad204 Project will involve the continued use of the existing Schiehallion and Loyal subsea infrastructure including the removal, re-installation or replacement of some existing subsea facilities and the addition of new subsea infrastructure. All of the existing production and water injection wells will continue to be used along with the existing production manifolds and these will be tied back to the new FPSO via a system of subsea flowlines and flexible risers. New subsea infrastructure will be installed as part of the Quad204 Project (Figure S.2) and includes five new production flowlines, one new dynamic umbilical, two new static umbilicals, six new risers and two new manifolds. To facilitate the replacement of the FPSO, while
maintaining system integrity, existing subsea infrastructure will need to be suspended between 2014 and 2015. The environmental implications of this task will be given due consideration, prior to the commencement of these activities.
Floating production, storage and offloading (FPSO) vessel The new FPSO will be designed for 25 years service and will be larger than the existing Schiehallion FPSO; measuring 270 m in length and 52 m in breadth with an operating draft of 14 to 20 m (Figure S.3). The hull of the FPSO will be of double-sided, double-bottomed construction, and will be designed with enhanced fatigue performance and corrosion resistance suitable for service in a harsh environment. The new FPSO will have accommodation onboard for 125 personnel although it will be able to accommodate approximately 168 personnel during periods of high activity such as hook-up and commissioning and turnarounds; this is an increase from the existing 123 personnel on the Schiehallion FPSO. The living quarters will be located at the aft end of the FPSO, to maximise the separation between the accommodation and the hydrocarbon processing facilities.
Figure S.2: Overview of potential new subsea infrastructure in the Quad204 Project area
November 2010
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Non-Technical Summary
Figure S.3: Artists impression of the new FPSO
FPSO installation and mooring The new FPSO will be permanently moored in its operating location by the turret mooring system allowing the vessel to move freely according to sea state and wind direction. Mooring lines will run from the turret to a series of new suction anchors on the seabed. There are currently 14 mooring lines installed for the existing Schiehallion FPSO, arranged in four bundles, with a total of 14 suction anchors. The new FPSO will require 20 new mooring lines arranged in four bundles and 20 new suction anchors. The anchors will be located at a slightly greater radius than the existing anchors (approximately 100 m further out) to allow installation prior to the removal of the existing FPSO. In addition the new FPSO will have three aft thrusters on board to be utilised during close approach work (e.g. heading control during offloading operations) and during times of challenging sea conditions (e.g. to minimise roll of the FPSO for oil separation and improve crew comfort). The installation of the new FPSO will involve the re-attachment of the existing umbilicals, risers and flowlines which will have been previously disconnected and left in situ, and the connection of any new umbilicals, risers and flowlines. Process facilities
production fluids from the wells, and a number of process systems are in place for subsequent treatment of these fluids. The main process systems in place on the new FPSO are illustrated in Figure S.4. The new FPSO has been designed to enable continued production from the Schiehallion and Loyal fields and any other future subsea tie-backs. Major effort has been made during design to remove or reduce environmental impact and to incorporate lessons learned from the existing Schiehallion FPSO. Produced fluids will be preheated and separated st nd into oil, gas and water in the 1 and 2 stage separators. The separator vessels will also include sand removal facilities. The oil will be cooled before being routed to the cargo oil tanks. The gas will be dried and compressed and used as fuel gas in the power generation system; some will be used for gas lift and the remainder will be exported via the WOSPS. The produced water will be treated to remove oil in order to meet the regulatory oil in water specification of 30mg/l with a target of 15mg/l. Following clean-up all produced water will be comingled with seawater and injected into the reservoir for pressure support. The water injection system availability is a critical part of ensuring oil production is maintained. The produced water reinjection (PWRI) system will be designed so that the required minimum availability of 95% and a target availability of 98% can be achieved.
The new FPSO will be designed to collect
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November 2010
Non-Technical Summary
Figure S.4: Simplified schematic of the new FPSO process systems
Flaring of gas during normal operational conditions is not expected. A full flare gas recovery system will be included on the new FPSO which will remove all routine flaring including purge flows, pilots or leaks, which will be returned to the process system. The Schiehallion asset has made major steps to reduce flaring with considerable reductions in gas to flare made since 1999. The introduction of a flare gas recovery system on the Quad204 FPSO will see even further reductions in gas to flare. Oil production Total oil production from the Schiehallion and Loyal wells is expected to peak at ca. 20,000 tonnes/day in 2016 following start-up of the new FPSO before steadily declining over field life, through natural depletion (Figure S.5). Gas production Total gas production is expected to peak 3 significantly in 2016 at ca. 3.5 million sm /day before steadily declining over field life, through natural depletion (Figure S.6). Produced water The new FPSO will be designed to handle significant quantities (49,300 m3/day (310 mbd)) of produced water. Figure S.7 shows the produced water profile for the Schiehallion and Loyal fields. Produced water is expected to November 2010
increase steadily following start-up in 2015 to ca. 45,000 tonnes/day and remain at this level through to 2035. Sand treatment and disposal Production fluids from the Schiehallion and Loyal fields contain significant quantities of solids (primarily sand) and there is a risk that sand production will continue to increase over field life. The existing Schiehallion FPSO has experienced a number of issues associated with sand. As a result the new FPSO will include maximum facilities for sand removal utilising proven technologies with options for additional enhancements. Cleaned sand will be disposed of overboard in slurry form. Power generation Power generation systems are critical to obtaining a high operating efficiency. The new FPSO will be self-sufficient in power generation and the system will comprise four dual-fuel turbine generators. Three of the turbines will be operational with one on standby as a non-running spare to ensure that gas compression facilities and water injection systems can remain operational. Waste heat from the turbine exhausts will be recovered in waste heat recovery units (WHRUs) and used to heat the process fluids.
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Non-Technical Summary Note: There will be no production between 2Q 2014 and 3Q 2015. Existing FPSO production will cease in 1Q 2014 with new FPSO production expected from 4Q 2015.
Figure S.5: Peak oil production forecast for Schiehallion and Loyal
Figure S.6: Peak gas production forecast for Schiehallion and Loyal
Figure S.7: Peak produced water forecast for Schiehallion and Loyal
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November 2010
Non-Technical Summary
Oil storage and export Export quality crude oil will be stored in the cargo oil tanks prior to offloading to a shuttle tanker. Total oil storage capacity will be approximately 172,560 m3 (1.08 million bbls), which is sufficient for a full export parcel, plus 2-3 days production ullage to allow for delays in export to the shuttle tanker. The shuttle tankers will transfer the oil to an onshore terminal or direct to market. Volatile organic compounds (VOCs) will be recovered on the shuttle tankers allowing significant reduction in VOC emissions.
Decommissioning The new subsea facilities design will allow for removal of subsea architecture in line with legislation, for subsequent possible re-use and recycling onshore. Dynamic umbilicals and risers that will not be re-used will be recovered in 2014 and disposed of using normal BP management processes. Subsea static umbilicals that are being replaced by new static umbilicals will be recovered at the end of field life. Table S.2 provides an overview of the decommissioning timetable.
Item
Approximate timescale for removal
Existing dynamic umbilicals that will not be re-used
2014
Existing risers that will not be re-used
2014
Existing FPSO
2015
Remaining subsea infrastructure
End of field life
New FPSO
End of field life
Table S.2: Decommissioning timetable
Despite decommissioning of the Quad204 facilities being many years away (the FPSO has a design life of 25 years), consideration of the implications of the decommissioning activities have been taken into account during project design. The overall decommissioning strategy for the Quad204 Project will be to ensure minimal impact on the marine environment and other sea users. Therefore, removal will be performed in such a way as to prevent any significant adverse effects. At the end of field life, a Decommissioning November 2010
Programme will be produced and submitted to DECC for approval, and decommissioning will be conducted to meet as a minimum the regulatory requirements in place at that time. A comparative assessment of the options by which this could be achieved will be prepared as part of the Decommissioning Programme submission for the Schiehallion and Loyal fields.
The environment An understanding of the environment in the vicinity of the Quad204 Project is based upon regional and site-specific environmental surveys and on research that has been carried out in the area during the life of the Schiehallion/Loyal field development. The focus is on the offshore areas around the FPSO and drill centres. Consideration has also been given to the coastal characteristics throughout the area that would be vulnerable in the unlikely event of a large oil spill. Water current patterns in this area are often complex with various strong non-tidal currents (particularly the warm Atlantic surface water that flows into both the Arctic basin and FaroeShetland Channel, but also cold bottom water originating from the Arctic basin and flowing southwards into the Faroe-Shetland Channel) interacting with relatively weak tidal flow. Water column stratification occurs during the summer months where a distinct boundary exists between the warmer surface and cooler bottom waters. Strong winds, particularly during the winter months, are characteristic of the northeast Atlantic and calm conditions are rarely recorded. This, in association with the long westerly fetch, generate an extreme wave regime in the area with wave heights in excess of 2.5 m recorded for 50% of the year. Southerly and westerly winds tend to dominate from July through to March, although a more even average wind distribution is recorded during the spring (April to June). Mean sea temperatures range between 7.5°C in February and 13°C in August at the surface, but can be as low as -0.5°C at 500 m water depth. The Quad204 Project lies in an area where the seabed is dominated by iceberg ploughmarks (relict scars in the seabed historically caused by the dragging of iceberg keels) which are generally orientated in a northeast to southwest direction throughout the area. Seabed surveys indicate that the surface sediment comprises a thin veneer of sand (although thicker within the identified ploughmarks). Underlying sediments are very soft to firm (occasionally stiff) sandy clays and silty Page xi
Non-Technical Summary clays with gravel and occasional pebbles. Previous surveys indicate that the sediment hydrocarbon and metals concentrations in the Quad204 Project area are at or lower than typical background levels.
Key environmental sensitivities Based on previous experience, studies and consultation, it has been possible to identify the key environmental sensitivities for the offshore environment of the Quad204 Project area. These are summarised in Table S.2.
Conservation interests No designated offshore conservations sites under Annex I of the EU habitats directive are present in the project area. Although the Quad204 Project lies in an area dominated by iceberg ploughmarks; a seabed type which has the potential to act as a Reef habitat (as listed under Annex I), the area is not of high conservation interest. The Joint Nature Conservation Committee (JNCC) is currently working to identify important ‘hotspots’ for seabids in the offshore area, including several areas around Shetland, with a view to designating marine Special Protection Areas (SPAs). However, as yet no offshore SPAs have been identified for feeding or overwintering. A number of marine species in UK waters have been identified for protection under Annex II of the European Habitats Directive. Those that are found in UK offshore waters are the grey seal, harbour seal, bottlenose dolphin and harbour porpoise. Of these, only the harbour porpoise is likely present in any numbers and with any regularity in the Quad204 Project area. Although the JNCC is seeking to identify areas suitable for designation for harbour porpoise, the species is widely distributed in UK waters and the area to the west of Shetland is not considered unique to these Annex II species. The European storm petrel has been nominated for inclusion in Annex I of the Birds Directive. Storm petrels are widely distributed over the whole shelf break west of Shetland between May and November.
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Orkney and Shetland are the closest land masses to the Quad204 Project and, in the unlikely event of a major oil spill occurring, may be affected. Both island groups are comprised of a large number of islands and skerries with numerous coastal habitats being designated as sites of international, European and national importance. Other potential sensitivities to oil spills in coastal areas include fishing, mariculture, tourism and amenity.
Assessment of potential impacts The main aim of the Quad204 environmental strategy has been to design out or reduce issues believed likely to impact on the environment or on users of the environment. Project design and operational planning has succeeded in the removal or reduction of many of the key environmental issues. Using data and understanding relating to the proposed design, the sensitivity of the environment and consultation feedback, the core task of the EIA process has been to: h Assess potential residual issues from the project, both from routine operations and possible accidental events h Define mitigation and management measures to be addressed during the detailed design phase and subsequent operations The following sections of the non-technical summary present the findings of the EIA for the residual environmental issues remaining following design and operational planning. The issues are addressed under the following categories: h Physical presence h Discharges to sea h Underwater noise h Atmospheric emissions h Waste h Accidental events The potential for cumulative or transboundary impacts is also addressed.
November 2010
Non-Technical Summary Plankton
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
A peak in phytoplankton (plant) productivity in late spring is followed by a lower, yet constant, productivity until autumn. Zooplankton (animal) productivity follows a similar pattern with a one or two month delay. Zooplankton provides an important source of food for many fish species. Plankton communities are not generally subjected to pressures from human activities.
Seabed animals
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Surveys show that the sediments in the Quad204 Project area support rich and relatively abundant assemblages of surface-living animal life. There is no evidence to suggest a seasonal sensitivity for seabed animals. An environmental review conducted in 2008 concluded that there was little evidence of major impacts on seabed animal life as a result of the current Schiehallion and Loyal field operations in the area.
Fish
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
The Quad204 Project area lies within the spawning and nursery areas for Norway pout and possible nursery areas for blue whiting and mackerel. The area also lies within a migratory route for mackerel and blue whiting to reach summer feeding grounds in the Norwegian Sea. However, sensitivity remains relatively low throughout the year as the identified spawning and nursery areas for these key fish species extend over much wider areas throughout UK and European waters.
Seabirds
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Northern fulmar, northern gannet, herring gull, great black-backed gull, black-legged kittiwake, common guillemot, razorbill and Atlantic puffin are present in the West of Shetland area all year round with many other species present at certain times of the year. Northern fulmar is the most abundant species in the Quad204 Project area. The European storm petrel (listed under Annex I of the EU Birds Directive) is present in the area in high densities during September and occurs in internationally important numbers. Seabird populations are particularly vulnerable to surface oil spills. Overall bird vulnerability to surface pollution is at its highest in March, May, June and September and moderate or low for the remainder of the year.
Cetaceans
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Interpretation of various sets of survey data indicates that the most abundant cetacean found in the Quad204 Project area is the Atlantic white-sided dolphin with highest densities occurring in June, July and September. Other cetaceans occurring in moderatehigh densities in the area include long-finned pilot whale, killer whale, sei whale, fin whale and sperm whale. The harbour porpoise has also been observed regularly in the Quad204 Project area. Sightings tend to peak during the summer months, although particular periods of sensitivity vary depending on the individual species.
Other sea users
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Commercial shipping in the area is predominantly associated with the route to and from Sullom Voe Terminal or with transatlantic shipping routes. No wrecks are identified within the immediate vicinity of the Quad204 Project area, and no military exercise areas are charted within the immediate locality. The nearest submarine cable (telecommunication and/or power) connects the Schiehallion field with the nearby Clair field to the east.
Fisheries
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
The waters around the Quad204 Project area support a mixed fishery of commercial importance, particularly for mackerel and herring. Fish species are characterised by both deepwater species at the upper limit of their range and species regarded as typical of the continental shelf at the lower limits of their range. The main commercial species exploited include mackerel, saithe, and monkfish. Fishing activity in the Quad204 Project area is comparatively limited with the majority of activity in the wider West of Shetland area located east of the Quad204 Project area along and around the 200 m depth contour. The limitations to fishing activity are also currently influenced by the existing 500 m exclusion zone around the existing Schiehallion FPSO. Fishing activity occurs all year round with fishing methods varying at different types of year.
General sensitivity
Low
Moderate
High
Table S.2: Summary of offshore environmental sensitivities
Physical presence
Seabed impacts
There are a number of activities being conducted during the Quad204 Project that have the potential to impact upon the seabed; these including drilling, anchoring of vessels and the installation/replacement of subsea structures.
Impacts resulting from the anticipated activities may result in the direct physical injury of benthic (seabed) species, the localised loss of seabed habitat or indirect impacts which may be caused by the re-suspension and re-settlement of sediments.
In addition, offshore activities associated with all stages of the project and the physical presence of vessels and subsea structures, could interact with other users operating within the same area of the marine environment.
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The Quad204 Project is a redevelopment project and much of the seabed likely to be affected by the proposed project activities will have experienced similar impacts during previous field development phases without any adverse environmental effects being incurred. Additionally, Page xiii
Non-Technical Summary interpretation of any likely impacts can be better assessed by drawing on previous operating history. Lessons learned from previous activities can be applied to further improve environmental performance during the Quad204 Project.
infrastructure will be placed within existing drill centre safety exclusion zones and flowline corridors.
The maximum area that will be directly impacted by placement of infrastructure on the seabed is estimated at 3.11 km2. In the context of the seabed available across the West of Shetland area, this is a very small area.
The increase in the number of vessels in the area during project activities will be of limited duration and will occur over a well-defined period of time. Standard communication and notification measures will be in place to ensure that all vessels operating in the area are aware of the project activities occurring. A standby vessel will also be present. Project activities will occur at the Schiehallion/Loyal field development, a recognised development area which is clearly marked on navigational and fishing charts and well known to other sea users that nake regular use of the area. As a result the temporarily increased vessel presence in the Quad204 Project area is expected to have little or no significant residual impact.
Biological communities in the project area are in a continual state of flux and are often able to either adjust to disrupted conditions or rapidly recolonise an area that has been disturbed. It is considered that the limited seabed area that may be affected by the placement of subsea structures is unlikely to contain species that are of conservation significance or that would be unlikely to recover in a short time period. Any anchor mounds that are generated will be eroded by the relatively strong bottom currents. Revovery of seabed affected by transient operations such as anchoring is expected to be rapid (less than five years) via sediment mobility and re-colonisation. Due to the nature of the seabed (sandy and silty sediments) levels of suspended sediments in the near-seabed water column within the project area are naturally high. Re-suspension of sediments will be restricted to the installation period and will not occur during the operational phase. Considering the above, any seabed impacts are unlikely to be significant and will be restricted to within the existing development footprint. Interaction with other sea users The marine environment within which the Quad204 Project will be located is utilised by a number of other sea users, primarily the fishing and shipping industries. The increase in vessel presence during installation and the physical presence of the subsea structures potentially increases the risk of collisions. In addition, the proposed activities, vessels and new subsea structures will potentially exclude areas of sea and seabed from use by other sea users and potentially increase the risk of fishing gear and catch being damaged through interaction with subsea structures. It is however, important to realise that the Quad204 Project area is already heavily used by the offshore oil and gas industry and that some of the structures being placed on the seabed will replace existing infrastructure and that all new Page xiv
Increased vessel presence
Fishing interaction Snagging risks cannot be eliminated entirely and a number of mitigation measures will be in place to reduce them as far as possible. Flowline routes will utilise existing corridors and any new subsea structures will be designed to be “fishing friendly”, continuing the practice already seen at Schiehallion. Information will be provided to the fishing industry through established BP fishing liaison channels. The area in which the work will occur is extremely well-developed in terms of offshore oil and gas exploration, therefore the additional infrastructure to be installed is very unlikely to disrupt previously unaffected fishing areas. Anchor mounds may pose a risk to fishing vessels. However, due to the temporary nature of anchor mounds (as discussed above), it is likely that the threat to fishing in the Quad204 Project area is minor.
Discharges to sea Discharges to sea can occur during the drilling, installation, commissioning and operational phases of the Quad204 Project. Likely impacts include increased suspended solids in the water column and alteration to the seabed topography and sediment structure. BP aims to reduce the impact of discharges on the environment, with emphasis placed upon pollution prevention and impact minimisation at source.
November 2010
Non-Technical Summary Drilling discharges
solids due to the species present.
Potential discharges to sea during drilling operations include cuttings, mud, cement and associated chemicals. Discharge of chemicals may also occur during any well workover or intervention activities.
WBM cuttings generated from drilling the tophole section of the well will be discharged to the seabed in line with current practice. Drill cuttings with WBM generated from drilling the middle section of the well will be discharged from the rig into the sea following cuttings cleaning and mud recovery operations in line with current practice. Existing procedures will be followed to contain and ship to shore for disposal OBM cuttings generated from drilling the lower section of the well and these will not be discharged to sea. There are no significant long term impacts expected from the Quad204 Project drilling operations.
Modelling results undertaken for the Quad204 Project show that any suspended particulates resulting from drilling are spatially restricted to the lower water column. It is unlikely that there will be any significant adverse impact on zooplankton feeding as these will generally be located higher in the water column. The water column impacts are expected to be short term and localised. Although there are a number of fish and shellfish species that can be found in the vicinity of the Quad204 Project, there are no commercial demersal species that are known to spawn in the area. Therefore there is unlikely to be significant impact on commercial fish species and fish spawning from the drilling activities. The contaminant loading of the WBM and chemicals to be used in the drilling activities will be risk assessed as part of the PON15 process prior to the use of any chemicals. In this way the potential adverse impact due to chemical composition of the solids in the water column will be minimised. The position of the cuttings on the seabed was predicted to cover a wide area although this predominantly resulted in a layer of less than 0.01 mm thick. The area of thickness centred on the well being between 1 mm and 130 mm with an elongated shape of 440 m by 140 m in a SW – NE: NW – SE direction. The presence or affect of which is unlikely to be detectable in the environment. Smothering or burial will be limited to the areas of sediment with the higher deposition, e.g. 10 mm thickness. In the areas where there is limited deposition, the infaunal organisms should not be smothered and should be able to move through this surface layer of deposition. As the increased suspended solids loading in the water column is not expected to be long term, the impact of this on the benthic species is considered to be low. There will be no deposition of an impermeable layer on the seabed and as result the infaunal species are expected to be able to relocate through the deposited material to their preferred depth. The impact from the deposition is not expected to result in major adverse impacts on the seabed other than immediately at the well location. There is likely to be a good potential for recovery of any seabed impacted by sedimentation of drilling November 2010
Commissioning discharges Chemicals will be required during subsea installation and pre-commissioning operations. The appropriate risk assessment for the use and discharge of these chemicals will be covered in the PON15 permitting system. The focus will be on selecting low dosage, low risk chemicals as far as possible. Although there will be discharges associated with these operations, they will be short-term and have only a localised effect, therefore the risk to the environment is assessed as negligible. Produced water As a result of the application of lessons learned from Schiehallion to the design and adoption of the produced water reinjection system (PWRI) system on the Quad204 FPSO the discharge of produced water including oil and chemicals will be considerably reduced as the produced water will be injected back into the reservoir. As the water injection system will be available immediately no commissioning discharges are expected as the water injection wells are already in place. As the PWRI system is designed to have at least 95% uptime the discharge of produced water is not expected to occur for long periods of time. The new FPSO will be designed so that any oil content is minimised with 15 mg/l as the target oil in water specification of the system. The potential impact of any intermittent produced water discharges will be mitigated by the rapid dispersion of produced water due to the strong currents and winds in the Quad204 area. The FPSO will also have off-spec tanks to cover any short outages of PWRI. Chemicals Production from the new FPSO will result in the requirement for chemical use and discharge. The chemical products required will be reviewed prior Page xv
Non-Technical Summary to commencement of operations and their use and discharge will be addressed by means of a PON15D application. Produced sand Produced sand from the cyclonic devices on the FPSO will periodically need to be batch discharged to sea at the surface. These discharges will involve very small quantities of particulate material and are unlikely to result in smothering and changes in grain size at the seabed due to the highly energetic environment in the Quad204 Project area and the depth of the water at the FPSO location.
Underwater noise The EIA has applied the most recent JNCC guidelines and included a detailed review of available data and scientific study results in order to establish an understanding of the potential significance of any potential impacts of underwater noise on marine mammals as a result of the Quad204 Project. Sources of noise generation from activities associated with the Quad204 Project which have the potential to impact upon marine species in the vicinity of the project will include pile driving, seismic survey, drilling, vessel presence and movements, and pipelay activities. It is known from previous study that the degree of impact of underwater noise on marine mammals is dependent on both the sound frequencies of the noise source, and the hearing frequencies of the marine mammals. Most marine mammals hear best at medium to high frequency. Noise generated from the Quad204 Project will be predominantly of low frequencies, thereby minimising the risk of significant disturbance to the majority of marine mammals likely to be within the vicinity of the project. Considering the short time period in which the anticipated noise sources will occur and also the nomadic behaviour of marine mammals (which implies that they will actually avoid loud noise sources), it is unlikely that any will be exposed to sound which would cause significant behavioural effects. Recognising the uncertainties in the assessment of impacts of underwater sound generation, BP is committed to contributing to the overall understanding of underwater noise in the West of Shetland region as part of a BP wide programme for noise data collection. Page xvi
Assessing the likelihood of an offence against a European Protected Species (EPS) The possibility of the pile driving noise causing an injury offence and non-trivial disturbance offence against an EPS under the Habitat Regulations and Offshore Marine Regulations has been assessed. Considering the nature of the piling activity and the mitigation measures that will adopted (JNCC guidelines for pile driving) no injury or disturbance offence is expected. BP therefore considers that application for an EPS licence is not required.
Atmospheric emissions The use of energy optimisation and BAT studies for power generation, and key design decisions regarding flaring and the use of hydrocarbon gas for cargo tank blanketing have sought to minimise the atmospheric emissions associated with the Quad204 Project. Throughout the installation, commissioning and operation of the Quad204 Project, there will be additional levels of CO2, NOx, SO2, CO and VOCs released into the environment. Releases from installation and commissioning vessels will be transitory and emissions from operational aspects will continue throughout the life of field. The effects from these pollutants will be localised and will not have a significant impact on the environment. The new FPSO is not expected to have a significant impact on the air quality at the nearest adjacent receptor (the Foinaven FPSO) or in the immediate Quad204 Project area. It is expected that the measures incorporated into the new FPSO design will result in overall improvements in terms of atmospheric emissions associated with oil and gas production from the fields.
Waste BP is committed to reducing waste generated and to managing all waste produced by applying approved and practical methods. BP is under a ‘Duty of Care’ to ensure that it handles all of its controlled waste safely and in compliance with the appropriate regulations. BP will develop a Waste Management Plan (WMP) for the Quad204 Project which will provide a structure for waste guidance and disposal at all stages during the project. The majority of waste currently generated offshore at the existing Schiehallion FPSO is sent for recycling including scrap metal, wood, plastic and other material. Most of the remaining wastes November 2010
Non-Technical Summary generated are as a direct result of oil and gas production and processing, e.g. produced water and drill cuttings. The largest volume of waste potentially generated during the Quad204 Project operations is likely to be OBM cuttings. These cuttings will be contained and shipped to shore for disposal. Residual impacts associated with waste from the Quad204 Project will be related to the emissions from transportation to shore and energy/resource use associated with the onshore treatment and disposal of these wastes. Considering BP’s commitment to reduce waste generation and to emphasise the importance or reuse and recycling, significant negative residual impacts are not expected.
of a failure of well control on Quad204 Project wells. The environmental impact which arises from an oil spill is highly complex and dependent on a number of factors including the size of the spill, the trajectory of the slick and the weather conditions upon occurrence. The greatest vulnerability to an oil spill at the Quad204 Project will be the presence offshore of vulnerable seabird populations at certain times of the year. To address the small residual risk of oil spill which remains, even with comprehensive prevention measures in place, BP implements a range of response/mitigation measures as detailed in the spill response strategy. Spill response strategy
Accidental events It is BP’s aim to cause zero damage to the environment and to minimise the risk of spills using a range of appropriate measures relating to plant, people and process. Therefore in light of the Deepwater Horizon incident in the Gulf of Mexico the ES also incorporates emerging relevant information from the incident whilst recognising that the Quad204 Project consists of development infill drilling into reservoirs which do not contain fluids at high pressure and temperature and in which more than 50 wells have been drilled since the discovery of the Schiehallion and Loyal fields in 1993 and 1994 respectively. Oil spills There is an extremely large effort put into the prevention of oil spills and the oil industry is always striving to improve by implementing lessons learned. The philosophy of the Quad204 Project is to reduce the likelihood of oil spill events at source through design and operational practices. Historically, small (< 1 tonne) installation spills are the most likely type of spill to occur. The Quad204 Project has focused on the prevention of these spills through FPSO specification, implementation of agreed operational procedures and through careful well and associated infrastructure design. The likelihood of a blowout event leading to a spill, particularly from the drilling of wells in reservoirs such as the Schiehallion and Loyal, is considered remote or extremely remote. Nevertheless as the consequences of a blowout are significant BP will implement measures to reduce the probability of a failure of well control or reduce the consequences November 2010
An Oil Pollution Emergency Plan (OPEP) is currently in place for the existing Schiehallion/Loyal field development. This will be updated, as appropriate to include all the drilling activities associated with the Quad204 Project and to reflect the increase in quantity of oil being extracted and handled by the new FPSO. The BP Onshore Oil Spill Plan is in place for the Schiehallion/Loyal, Foinaven and Clair fields in addition to the immediate offshore response. As part of this plan, BP have contracted Oil Spill Response Limited (OSRL) to have strategically located mobile response packages, and trained response personnel, that can be engaged to combat oil spills approaching inshore areas. This plan will be reviewed and modified to incorporate any changes required for the inclusion of the Quad204 Project. Detailed and fully tested oil spill response strategies, appropriate to the local environmental sensitivities will be developed and finalised for both drilling and production prior to the commencement of operations. These will be documented in the OPEPs for the drilling rig and the Quad204 FPSO. The OPEPs will consider, and where appropriate, incorporate information gained from the Deepwater Horizon incident in the Gulf of Mexico. The OPEPs will be submitted for approval to DECC in sufficient time to allow full consideration of the proposals. Chemical spills As with oil spills, BP’s target is for zero chemical spills. However, despite design, operational and training measures to reduce the probability of chemical spills, there still remains a risk. To reduce the potential chemical spill risk from Page xvii
Non-Technical Summary chemicals used offshore, BP continually works with its chemical suppliers to ensure that chemical use is minimised, wherever possible, without compromising technical performance. Given the high energy marine environment of the Quad204 Project area, any chemical spill is expected to rapidly disperse with a possible negligible to minor localised impact on plankton or fish egg/larvae, depending on the season. The low probability of a chemical spill occurring with any significant associated environmental impact means the residual risk of chemical spill will be remote.
Cumulative and transboundary impacts Cumulative effects are those that impact on the environment outside the local scale and those that add to existing or reasonably foreseeable future impacts. Transboundary effects are those impacts where the area of influence could reasonably be expected to extend beyond the UK boundary line into either Faroese, or Norwegian waters. The Quad204 Project is located approximately 35 km from the UK/Faroe median line and 330 km from the UK/Norway median line. The Quad204 Project is the redevelopment of the Schiehallion and Loyal fields in the West of Shetland. Other oil and gas fields currently developed in the West of Shetland area include the Foinaven and Clair fields. In addition the Laggan and Tormore fields are currently under development. The Alligin field is a potential future development that could be tied back to the new FPSO. The main aim of the Quad204 Project environmental philosophy has been to design out or reduce issues believed to present significant risk to the environment or users of the environment. Project planning and design has succeeded in the removal or substantial reduction of many of the key issues such as discharges of produced water and associated chemicals to sea and atmospheric emissions from routine flaring. Modelling of residual discharges to sea and atmospheric emissions from the Quad204 Project indicated that these are not expected to have detrimental impacts on the local environment either individually or in cumulation with other vessel operations within the region. No transboundary issues from discharges to sea or atmospheric emissions will occur. Due to the localised nature of any impact, cumulative and/or transboundary impacts associated with the physical disturbance of the seabed, or with the generation and propagation of Page xviii
underwater noise are considered highly unlikely. As indicated by historical data, the likelihood of one major spill occurring is remote or extremely remote. A catastrophic oil spill occurring on two installations in the West of Shetland area simultaneously is not considered to be a credible scenario, due to the stringent regulations and controls under which all activities are conducted. This therefore limits the potential cumulative impact from the Quad204 Project and other installations in the area. Detailed contingency plans are in place for each installation outlining the response measures to be implemented in the event of any spill. Oil spill modelling has been undertaken to predict if there is any likelihood of potential oil spills impacting on foreign waters. The modelling, which assumed no response measures were implemented, indicates some probability that in the event of a worst case oil spill, oil could move across international boundaries, particularly into Norwegian waters. The assessment of spill likelihood, based on historical UKCS incident data, demonstrates that the likelihood of a spill large enough to lead to such a transboundary impact is remote - extremely remote, i.e. of low probability. The Espoo convention requires notification and consultation on projects likely to have a significant adverse environmental impact across boundaries. Therefore BP believes that consultation under the Espoo convention is not required as a result of the Quad204 Project. The risk of oil spill having transboundary impact, particularly from North Sea operations, is recognised by the UK Government and other governments around the North Sea. Agreements are in place for dealing with international oil spill incidents with states bordering the UK. In the event of a major spill which is predicted to drift into Norwegian waters the NORBRIT plan will be activated. The NORBRIT plan is a joint UK/Norway oil spill contingency plan operating within the framework of the 2006 National Contingency Plan. The plan is oriented towards major spills resulting from, for example, blowouts. It becomes operational when agreement to the request for its implementation is reached. Responsibility for implementing joint action rests with the Action Coordinating Authority (ACA) of the country on whose side of the median line a spill originated. The UK’s Counter Pollution Branch of the Maritime and Coastguard Agency (MCA) is the ACA for the UK. In the event of a major spill which is predicted to drift into Faroese waters the MCA will liaise with the Marine Rescue and Co-ordination Centre November 2010
Non-Technical Summary (MRCC) in Torshavn, Faroe.
The way forward The Quad204 Project is a redevelopment of the Schiehallion and Loyal fields and the area in which the operations will occur is already developed in terms of offshore oil and gas production. Redevelopment has presented an opportunity to improve environmental performance in key areas and environmental considerations have played an important role in the decision-making process throughout the Quad204 Project and will continue to do so during detailed design, installation and operational activities. During the conceptual design and initial engineering stages of the project, many key decisions were made, leading to removal or major reduction in activities considered likely to have significant impacts on the environment when considered against the baseline of existing oil and gas activity in the area. The new FPSO will bring about environmental improvements when compared to the previous vessel, through improved efficiency of operation and the application of modern industrial technology in various areas, for example: h A centralised electrical power generation system with waste heat recovery from the turbine exhausts removes the need for separate fired heaters or large electrical heaters. It also offers a high degree of operational flexibility coupled with high uptime, high efficiency and relatively low CO2 emissions when compared to a direct drive option
previous system
Key residual issues Overall it is considered that, following application of management and mitigation measures identified within this ES, the Quad204 Project will not cause any significant residual environmental impacts. However there are aspects of the project that will need to be managed sensitively in order to minimise potential environmental effects. These include the following key residual issues: h Underwater noise – pile driving is seen as the activity generating the greatest underwater noise levels that may have potential impacts on marine mammals. The long-term presence of vessel noise also needs consideration. BP will employ a number of measures to mitigate noise impacts based on the principles of the JNCC guidelines for specific activities. Some operational noise such as that from FPSO and shuttle tanker thrusters will be intermittent but will continue for field life, and along with other noise sources will contribute to a noise ‘footprint’ at the location for field life. h Risk of oil spills – the focus of the Quad204 Project has been on spill prevention. The highlighted prevention methods will considerably reduce the risk of oil spill. However, a residual risk remains and therefore an oil spill response strategy has been developed. This strategy will be detailed in the OPEP which will include further consultation with the statutory authorities and appraisal of existing response arrangements.
h The flaring philosophy for the Quad204 Project is not to flare gas routinely during normal operations, and to have a closed flare system with flare gas recovery in order to reduce atmospheric emissions such as CO2, NOx, SOx and unburned hydrocarbons h VOC emissions will be reduced by the use of hydrocarbon gas blanketing in the crude oil storage tanks; which is recycled back through the process, and the use of shuttle tankers with VOC recovery systems during tanker offloading operations h Produced water and its associated chemicals will be routinely re-injected into the reservoir, thus significantly reducing potential impacts on the water column. Improved engineering design will enhance reliability compared to the November 2010
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Non-Technical Summary
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Abbreviations and Glossaries
Abbreviations ADMS Atmospheric Dispersion Modelling System
CFC Chlorofluorocarbon CHARM Chemical Hazard Assessment and Risk Management CH4 Methane
AEA Atomic Energy Authority cm Centimetre AFEF Atlantic Frontier Environmental Forum AFEN Atlantic Frontier Environmental Network
CO Carbon Monoxide CO2 Carbon Dioxide CO2e Carbon Dioxide Equivalent
AoS Area of Search COT Cargo Oil Tank API American Petroleum Institute cP Centipoise AQO Air Quality Objectives CPR Continuous Plankton Recorder ASCII American Standard Code for Information Interchange ASCOBANS Agreement on the Conservation of Small Cetaceans of the Baltic and North Sea
CPT Cone Penetration Test CRA Collision Risk Assessment cSAC Candidate Special Area of Conservation
BaSO4 Barium Sulphate (Barite) CS Continental Shelf BAT Best Available Technique bbl Barrel (6.2898 barrels = 1 m3)
Cu Cubic dB Decibel
BEP Best Environmental Practice BERR Department for Business Enterprise and Regulatory Reform BGS British Geological Survey BODC British Oceanographic Data Centre
DECC Department of Energy and Climate Change DEFRA Department of Environment, Food and Rural Affairs DepCon Deposit Consent
BoD Basis of Design
DHFC Downhole Flow Control
BOP Blowout Preventer
DHSV Downhole Safety Valve
BPEO Best Practicable Environmental Option
DLE Dry Low (NOX) Emissions DP Dynamic Positioning
CaCO3 Calcium Carbonate CaSO4 Calcium Sulphate CALM Catenary Anchor Leg Mooring CAPEX Capital Expenditure CCGT Combined Cycle Gas Turbine CDA Controls Distribution Assembly CEFAS Centre for Environment, Fisheries and Aquaculture Science
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DREAM Dose Related Risk and Effect Assessment Model dSAC Draft Special Area of Conservation DSV Diving Support Vessel DTHT Drill Through Horizontal Trees DTI Department of Trade and Industry (now DECC) E East
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Abbreviations and Glossaries
EC European Community
FPSO Floating Production Storage and Offloading (vessel)
ECE Environmentally Critical Equipment EC50 Median Effective Concentration EEC European Economic Community EEMS Environmental Emissions Monitoring System
FRS Fisheries Research Services (now Marine Scotland Science) FSU Floating Storage Unit FTA Flowline Termination Assembly g/cc Gram per cubic centimetre
EIA Environmental Impact Assessment GDP Group Defined Practice EIAIW East Icelandic Arctic Intermediate Water
GEBCO General Bathymetric Chart of the Oceans
EIF Environmental Impact Factor GHG Greenhouse Gas EIMP Environmental Impact Management Process EMS Environmental Management System ENE East North East ENVID Environmental Issues Identification EOR Enhanced Oil Recovery EPR Environmental Performance Requirement
GHSSER Getting HSSE Right GIS Geographic Information System GOR Gas to Oil Ratio GT Gas Turbine GWP Global Warming Potential HC Hydrocarbon HCFC Hydrochlorofluorocarbon
EPS European Protected Species ERNP Environmental Requirements for New Projects (replaced by Environment GDP)
HCMS Harmonised Mandatory Control Scheme HOCNF Harmonised Offshore Chemical Notification Format
ES Environmental Statement HP High Pressure ESAS European Seabirds at Sea Hr Hour ESD Emergency Shut Down HR Habitats Regulation ESE East South East HSE Health & Safety Executive ESS Expandable Sand Screen HSE Health Safety and Environment ETS Emissions Trading Scheme EU European Union FDP Field Development Plan FEED Front End Engineering Design FEPA Food and Environment Protection Act FGR Flare Gas Recovery FOOCG Fisheries and Offshore Oil Consultative Group
HSSE Health Safety Security and Environment HUC Hook-up and Commissioning HVAC Heating Ventilation and Air Conditioning Hz Hertz H2S Hydrogen Sulphide IAPP International Air Pollution ICES International Council for the
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Abbreviations and Glossaries Exploration of the Sea IG Inert Gas IGG Inert Gas Generator
mbwd Thousand Barrels of Water per Day MCA Maritime and Coastguard Agency MCS Marine Conservation Society
IOPP International Oil Pollution Prevention
MDBRT Measured Depth Below Rotary Table
IPCC Intergovernmental Panel on Climate Change
MEHRA Marine Environment High Risk Area
IPPC Integrated Pollution Prevention and Control Regulations
MEMW Marine Environmental Modelling Workbench MFA Marine Fisheries Agency
IRM Intervention, Repair and Maintenance ISO International Standards Organisation JNCC Joint Nature Conservation Committee KBR Kellogg Brown and Root KCl Potassium Chloride kHz Kilohertz KIMO Kommunenes Internasjonale Miljøorganisasjon KISCA Kingfisher Information Service Cable Awareness km Kilometre km
2
Square Kilometres
LAT Lowest Astronomical Tide LC50 Median Lethal Concentration LOMS Local Operating Management System LP Low Pressure LSA Low Specific Activity (referring to radioactive substances) LWI Light Well Intervention MarLIN Marine Life Information Network MARPOL International Convention for the Prevention of Pollution from Ships m Metre m3 Cubic Metres mbd Thousand Barrels per Day
November 2010
mg Milligram mg/l Milligram per Litre ML Multi Lateral mMD Metres Measured Depth MMO Marine Mammal Observer mmscf Million Standard Cubic Feet mmscfd Million Standard Cubic Feet per Day MNAW Modified North Atlantic Water MoD Ministry of Defence MODU Mobile Offshore Drilling Unit MPcp Major Projects Common Process MSS Marine Scotland Science MW Megawatt M Metre mm Millimetre m/s Metres per Second NATO North Atlantic Treaty Organisation NAW North Atlantic Water NESS North East Storm Study NEXT North East Storm Study Extension N North NNE North North East NNW North North West nm Nautical Mile
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Abbreviations and Glossaries
NMHC Non Methane Hydrocarbon nmVOC Non Methane Volatile Organic Carbon NOCS National Oceanography Centre, Southampton
OSPAR Oslo and Paris Convention for the Protection of the Marine Environment of the North East Atlantic OSRL Oil Spill Response Limited Pa Pascal
NOEC No Observed Effect Concentration PAH Poly Aromatic Hydrocarbons NORM Naturally Occurring Radioactive Material
PARLOC Pipeline And Riser Loss Of Containment
NOX Nitrogen Oxides PBLJ Paul B Loyd Junior NPV Net Present Value NSAIW Norwegian Sea Arctic Intermediate Water
PEC Predicted Environmental Concentration PEXA Practice and Exercise Area
NSDW Norwegian Sea Deep Water NWAD North West Area Development N2O Nitrous Oxide OBE Ocean Biogeochemistry and Ecosystems
PIMS Pipeline Integrity Management Scheme PLONOR Poses Little or No Risk PM Particulate Matter PNEC Predicted No Effect Concentration
OBM Oil Based Mud POB Personnel on Board OCR Offshore Chemicals Regulations PON Petroleum Operation Notice OGP International Association of Oil and Gas Producers
POPA Prevention of Oil Pollution Act
OHGP Open Hole Gravel Pack
ppb Parts per Billion
OIC Orkney Islands Council
ppm Parts per Million
OMR Offshore Marine Regulations OMS Operating Management System
psi Pounds per Square Inch pSAC Possible Special Area of Conservation
OPEP Oil Pollution Emergency Plan pSPA Possible Special Protection Area OPEX Operating Expenditure PTS Permanent Threshold Shift OPF Organic Phase Fluid PW Produced Water OPOL Offshore Pollution Liability Association OPPC Oil Pollution Prevention and Control Regulations
PWA Pipeline Works Authorisation PWRI Produced Water Re-Injection Q1 First Quarter
OPRC Oil Pollution Preparedness Response and Cooperation Regulations
Q2 Second Quarter Q3 Third Quarter
OSCAR Oil Spill Contingency and Response Q4 Fourth Quarter OSIS Oil Spill Information System ROV Remotely Operated Vehicle
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Abbreviations and Glossaries
RSPB Royal Society for the Protection of Birds RYA Royal Yachting Association S South SAC Special Area of Conservation SAS Stand Alone Screens SAST Seabirds at Sea Team SCANS Small Cetaceans in the European Atlantic and North Sea
SOTEAG Shetland Oil Terminal Environmental Advisory Group SOx Sulphur Oxides SPA Special Protection Area SPU Strategic Performance Unit SRDL Satellite Relay Data Loggers SrSO4 Strontium Sulphate SSE South South East SSW South South West
scf Standard Cubic Feet SSSI Special Site of Scientific Interest scf/stb Standard Cubic Foot per Stock Tank Barrel SCI Site of Community Importance
STL Submerged Turret Loading SURF Subsea Umbilical Riser and Flowline
SCM Subsea Control Module SVT Sullom Voe Terminal SCPS Shetland Coastal Protection Strategy SEA Strategic Environmental Assessment SEL Sound Exposure Level SEPA Scottish Environment Protection Agency
SW South West SWOT Strength Weakness Opportunity and Threat TAR Turn Around TASC Trans-Atlantic Study of Calanus TD Total Depth
SERPENT Scientific and Environmental ROV Partnership using Existing Industrial Technology
Te Tonne Th Thermal input
SFA Shetland Fishermen’s Association THC Total Hydrocarbon Concentration SFF Scottish Fishermen’s Federation TLP Tension Leg Platform SHEFA Shetland-Faroes TTS Temporary Threshold Shift SIC Shetland Islands Council SICMPCP Shetland Islands Council Marine Pollution Contingency Plan
UETA Umbilical End Termination Assembly UHC Unburnt Hydrocarbon
SINTEF The Foundation for Scientific and Industrial Research sm3/day Standard Cubic Metre per Day
UK United Kingdom UKAPP United Kingdom Air Pollution Certificate
SMRU Sea Mammal Research Unit UKCS United Kingdom Continental Shelf SNH Scottish Natural Heritage SOLAS Safety of Life at Sea SOPEP Shipboard Oil Pollution Emergency Plan
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UKHO United Kingdom Hydrographic Office UKOOA United Kingdom Offshore Operators Association
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Abbreviations and Glossaries
UKMMAS United Kingdom Marine Monitoring and Assessment Strategy VOC Volatile Organic Compound VIEC Vessel Integral Electrostatic Coalescer VIP Value Improving Practice VLCC Very Large Crude Carrier VRU Vapour Recovery Unit W West WBM Water Based Mud WFD Waste Framework Directive WHRU Waste Heat Recovery Unit WNW West North West WMP Waste Management Plan WOSPS West of Shetland Pipeline System WPF Water Phase Fluid WSW West South West Wt% Percentage Weight % Percentage °C Degrees Centigrade 4D Four Dimensional µg/g Microgram per Gram µg/m3 Microgram per Cubic Metre μM Micro-Molar μPa2-s Micro Pascal per Second " Inch > Greater than < Less than
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November 2010
Abbreviations and Glossaries
Glossary Annex I Habitat Habitat, listed on the Habitats Directive, considered most in need of conservation within Europe. Annex II Species Species (not including birds), listed on the Habitats Directive, considered most in need of conservation within Europe. Anthropogenic Relating to human activities (or man-made). Area of Search (AoS) In UK offshore waters the JNCC has outlined AoS as potential future offshore SACs (see SAC) based upon the best available evidence of the location of Annex I habitats. Annulus The tube shaped void between a pipe string and a surrounding pipe string or formation. Appraisal well A well drilled to confirm the size or quantity of an oil discovery. Before development, a discovery is likely to need at least two or three such wells. Auks Birds of the family Alcidae in the order Charadriiformes. Barrels The traditional unit of measure of oil volume, equivalent to 159 litres (0.159 m3) or approximately 35 imperial gallons. Bathymetry The measurement of water depths in oceans, seas and lakes. Benthic Adjective pertaining to anything related to the sea bed. Benthos The plant and animal community of the bottom of the sea, including littoral and sublittoral components. Best Available Technique The latest stage of development (state of the art) of processes, of facilities or of methods of (BAT) operation, which indicate the practical suitability of a particular measure for limiting discharges, emissions and waste. Definition of available includes demonstrated techniques, timescale as well as economic considerations. "Techniques" include both the technology used and the way in which the installation is designed, built, maintained, operated and dismantled. Best Environmental Option The development option that offers the minimal environmental impact assuming no technical limitations. Best Practicable The development option that offers most benefits and least damage to the environment Environmental Option within technical means, at acceptable cost in the long as well as the short-term. Biodiversity/Diversity The diversity of plant and animal life. Diversity is the measure of the variety of species contained within a habitat. Biota The plant and animal life of a particular region. Bioturbation The mixing of sediments or particles by fauna. Birds Directive European directive to protect habitats of wild bird species through the designation of SPAs. The directive provides a framework for the conservation and management of, and human interactions with, wild birds in Europe. The objective is to create a coherent network of protected species which meets the protection requirements of endangered and migratory bird species. Blowout Uncontrolled release of reservoir fluids into the wellbore and sometimes to the surface wellbore or casing. Blowout preventer Hydraulically operated device used to prevent uncontrolled releases of oil or gas from a well. Boreal Of the north or northern regions.
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Abbreviations and Glossaries
C130 Hercules A four engine turboprop military transport aircraft. Catenary Anchor Leg This offloading system is a coupled dynamic system in which the attached mooring and Mooring (CALM) buoy offloading lines, the FPSO, and the shuttle tanker influence the motions of the CALM buoy. offloading Cement Used to set casing in the well bore and seal off unproductive formations and apertures. It is also used as a coating to add weight to submarine pipelines. Cetaceans Collective term for whales, dolphins and porpoises. Chlorophyll This is a green pigment found in all plants, algae, and blue-green algae. Chronic Recurring intermittently over a long period. Completion See Well Completion. Conductor The conductor extends from the drilling deck to the seabed and provides a guide and access to the well and seals to enable circulation of the drilling fluid. Conspecific Of or belonging to the same species. Control umbilical Used for control and operation of subsea production, subsea processing and subsea injection facilities. Corrosion The eating away of metal by chemical action or an electrochemical action. The rusting and pitting of pipelines, steel tanks, and other metal structures is caused by a complex electrochemical action. Corrosion inhibitors prevent or delay this process. Corrosion inhibitors Delays the process of corrosion on metal. Continental shelf Continental shelf or the area at the edges of a continent from the shoreline to a depth of 200 m, where the continental slope begins. The shelf is commonly a wide, flat area with a slight seaward slope. Continental slope This is the seaward border of the continental shelf. Commissioning Preparatory testing work, servicing etc. usually on newly installed equipment prior to coming into full production. Completion Generic term used to describe the assembly of downhole tubulars and equipment required to enable safe and efficient production from an oil or gas well. Copepod A large family of aquatic belonging to the class Crustacea of the phylum Arthropoda, living in fresh water or sea water. Many are free living in the plankton or in seabed sediments, whilst others are parasitic. Cuttings pile A pile formed on the seabed as a result of the deposition of drill cuttings. Decibel (dB) A unit used in the comparison of two power levels relating to sound (one tenth of a Bel). Decommissioning Shutdown of the development with system cleaning and dismantling of facilities. Demersal Living or occurring in the water at the bottom of a water body. Demulsifier A chemical used to break down crude-oil water emulsions. The chemical reduces the surface tension of the film of oil surrounding the droplets of water. The water then settles to the bottom of the tank. Development well Any well drilled in the course of extraction of reservoir hydrocarbons, whether specifically a production well or injection well. Drill bit A drilling tool used to cut through rock.
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Abbreviations and Glossaries
Drill cuttings Chips and small fragments of rock generated while drilling a well, which are brought to the surface by the flow of the drilling mud as it is circulated. Drilling mud Special clay, water and chemical additives, pumped downhole through the drill pipe and drill bit. The mud cools the rapidly rotating bit, lubricates the drill pipe as it turns in the well bore, carries rock cuttings to the surface and serves as a plaster to prevent the wall of the borehole from collapsing. Drill string Lengths of steel tubing roughly 10 m long screwed together to forma pipe connecting the drill bit to the drilling rig. It is rotated to drill the hole and delivers the drilling fluids to the cutting edge of the drill bit Duty of Care This is a requirement that a person/organisation act toward others and the public with watchfulness, attention, caution and prudence that a reasonable person/organisation in the circumstances would. If a person's/organisation’s actions do not meet this standard of care, then the acts are considered negligent, and any damages resulting may be claimed in a lawsuit for negligence. Dynamic positioning Use of thrusters (instead of anchors) to maintain the position of a vessel. Echolocation The locating of objects using reflected sound. Ecosystem Consists of all the organisms living, including non-living physical components of the environment, with which they interact – a biological community and its physical environment. Environmental Impact Systematic review of the environmental effects a proposed project may have on its Assessment (EIA) surrounding environment. Environmental System established to manage an organisation’s processes and resultant environmental Management System impacts. (EMS) Environmental Statement Formal document presenting the findings of an EIA process for a proposed project. (ES) Epifauna Benthic organisms that inhabit the surface of the seabed. Faults A fracture in rock where there has been an observable amount of displacement. Fauna This is all of the animal life of any particular region or time. Flare A vent for burning of unwanted gases or to burn off hydrocarbons which, due to temporary malfunction or maintenance of process plant, cannot be safely stored or retained in process vessels. Flowline Pipe laid on the seabed for the transportation of production or injection fluids. It is generally an infield line, linking a subsea structure to another structure or to a production facility. Its length ranges from a few hundred meters to several kilometres. Formation fluids Any fluid that occurs in the pores of a rock. Strata containing different fluids, such as various saturations of oil, gas and water, may be encountered in the process of drilling an oil or gas well. Formation damage Damage to the reservoir rock around a well due to e.g. plugging with mud, infiltration by water from the well or high flow rate. Fugitive emissions Small chronic escape of gas and liquids from equipment and pipework. Habitat An area where particular animal or plant species and assemblages are found, defined by environmental parameters. Gas lift Increasing the production flow of oil by injecting gas down a well where it mingles with the oil, thus increasing pressure and flow rate.
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Abbreviations and Glossaries
Greenhouse gas Gases in the atmosphere that adsorb and emit radiation within the thermal infrared range. Primary greenhouse gases include water vapour, carbon dioxide, methane, nitrous oxide and ozone. Habitats Directive The Habitats Directive (together with the Birds Directive) forms the cornerstone of Europe's nature conservation policy. It is built around two pillars: the Natura 2000 network of protected sites and the strict system of species protection. All in all the directive protects over 1.000 animals and plant species and over 200 so called "habitat types" (e.g. special types of forests, meadows, wetlands, etc.), which are of European importance. Hook-up The activity following offshore development installation during which all connections and services are made operable for commissioning and start-up Hull The body or frame of a ship, most of which is under the water. Hydrates Crystalline solids composed of gas molecules trapped inside water molecules. They are stable in low temperature and relatively high pressures. Once hydrocarbon hydrates are formed. They can plug pipelines and significantly affect production operations. Hydrocarbons Organic chemical compounds of carbon and hydrogen atoms. There are a vast number of these compounds and they form the basis of all petroleum products. They may exist as gases and liquids. Examples include methane, hexane and asphalt. Hydrocyclone A centrifuge used to separate fluids/materials in fluids of different densities, typically used to separate oil from produced water. Hydrographic The study, description and mapping of waterways, including seas, lakes, rivers. Hydrophones Underwater microphones used for recording subsea noise. Hydrostatics Is the science of fluids at rest. Hydrotest A pressure test using water. ICES rectangles A statistical area of the sea that is 0.5° North by 1° West, defined by the International Council for the Exploration of the Sea. Inert gas This is a non-reactive gas. Intervention The downhole re-entry of a well inside the existing completion equipment. Jacket The structure of an offshore steel piled platform which supports the topside facilities Jumper A short pipe (flexible or rigid) sometimes used to connect a flowline to a subsea structure or two subsea structures located close to one another. Macrobenthic Organisms living in or on aquatic substrates and large enough to be seen with the naked eye. Macrofauna Benthic organisms that are retained in a 0.3 mm sieve. Manifold An area where pipelines entering and leaving a pumping station converge and that contains all valves for controlling the incoming and outgoing streams. Masking Perception of biologically important sounds is decreased due to interference by sound energy from other sources (including ambient noise). Mat/Mattress A structure to support and protect the lay down head and pig launcher/receiver during installation and pre-commissioning activities and to provide any additional dropped object protection to the pipeline and tie-in spool arrangement. Migration Any regular animal journey along well-defined routes, particularly those involving a return to breeding grounds.
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Abbreviations and Glossaries
Mitigation Process that would make a consequence less severe. Mud This is generally synonymous with drilling fluid and encompasses most fluids used in hydrocarbon drilling operations, especially fluids that contain significant amounts of suspended solids, emulsified water or oil. Mud includes all types of water-based, oil-based and synthetic-based drilling fluids. Mysticete Any whale in the taxon Mysticeti; a mysticete is a whale that has baleen instead of teeth. Mysticetes are filter feeders, straining water through their baleen to capture prey items. Mysticetes include the largest of the whales, the fin and blue whales. Natura 2000 An EU wide network of nature protection areas established under the 1992 Habitats Directive. NORBRIT Agreement A joint counter pollution operation between Norway and the UK in the zone extending 50 nautical miles either side of the median line separating the UK and Norway continental shelf. Odontocete Any whale from the taxon Odontoceti, an odontocete is a toothed whale. Sperm whales and beaked whales are both examples. Otter trawl See trawling. Paul B Loyd Junior An Aker H-42 design semi submersible drilling unit capable of operating in harsh environments. Pelagic Referring to the ocean water column and the organisms living therein. Phytoplankton Microscopic planktonic plants, e.g. diatoms and dinoflagellates. Piling Tubular steel shafts driven into the seabed to anchor a structure. Pilot hole This is a smaller hole drilled prior to a larger hole being drilled widening the hole to the desired width. Pinnipeds Marine mammals that include the seals, sea lions and walruses. Plankton Tiny plants and animals that drift in the surface water of seas and lakes. Of great economic and ecological importance as they are a major component of marine food chains. Pollution The introduction by man, directly or indirectly, of substances or energy to the marine environment resulting in deleterious effects such as harm to living resources; hazards to human health; hindrance of marine activities including fishing, and impairment of the quality for use of seawater and reduction of amenities. Polychaete Bristle worms. A class of segmented worms belonging to the phylum Annelida, generally marine. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. Pressure rating The operating aawinternal pressure of a vessel tank or pipe used to hold or transport. Produced water The water produced along with oil and gas from the reservoir, initially comprising the formation water, then also injection water. It contains a range of inorganic and organic compounds. Production well A development well specifically for the extraction of reservoir fluids. Production is the fullscale extraction of oil and gas reserves. Ramsar site Statutory areas designated by the UK Government under the Ramsar Convention (the Convention on Wetlands of International Importance) especially as waterfowl habitat. Recruitment Young fish joining the main adult fish population.
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Abbreviations and Glossaries
Reservoir A porous, permeable sedimentary rock formation containing quantities of oil and or gas enclosed or surrounding by layers of less-permeable or impervious rock; a structural trap; stratigraphic minerals. Riser A pipe that goes upwards from the seabed to the surface that is used to transfer produced fluids (oil, gas and water). Risers may be rigid or flexible. Salinity The saltiness or dissolved salt content of a body of water. SCI Site of Community Interest Sedentary Remaining or living in one area, not migratory. Seismic survey A survey conducted to map the depths and contours of various rock strata by timing the reflections of sound waves. 2-D seismic surveys measure depths from the reflections. 3-D seismic takes simultaneous oblique measurements that provide a more accurate picture. 4-D seismic incorporates time as the 4th dimension to a standard 3-D seismic survey. Separator A pressure vessel used for the separating well fluids into gaseous and liquid components with the aid of chemicals and heat. Sessile An organism that is attached to another structure by its base and is unable to move freely. Shoal Sandbar (or just bar in context), or gravelbar is a somewhat linear landform within or extending into a body of water, typically composed of sand, silt or small pebbles. Slick-line techniques Used to run and retrieve tools and flow control equipment in the well. Slurry A thick suspension of solids in a liquid. Side scan sonar A form of sonar used to create an image of areas of the seafloor. Uses include creation of charts, identification of bathymetrical features and detection of objects on the seafloor. Sidetrack This term is used for drilling a directional hole to bypass an obstruction in the well that cannot be removed or damage, such as collapsed casing that cannot be repaired. Sidetracking is also done to deepen a well or to relocate the bottom of the well in a more productive zone, which is horizontally removed from the original well. Source level Defined as the sound intensity, in decibels above a reference level, at a point which is a unit distance from a source (1 m is often used) and on an axis of the source. Spawning Reproductive stage of fish and other marine animals when eggs are released into the water column or deposited on to the seabed or other substrata. Special Area of Areas considered important for certain habitats and non-bird species of interest in a Conservation (SAC) European context. One of the main mechanisms by which the EC Habitats and Species Directive 1992 is implemented. In addition, there are four designations below full SAC status: Sites of Community Importance (SCIs) are sites that have been adopted by the European Commission but not yet formally designated by the government of each country; Candidate SACs (cSACs) are sites that have been submitted to the European Commission, but not yet formally adopted; Possible SACs (pSACs) are sites that have been formally advised to UK Government, but not yet submitted to the European Commission; and Draft SACs (dSACs) are areas that have been formally advised to UK government as suitable for selection as SACs, but have not been formally approved by government as sites for public consultation. Special Protection Area Sites designated under the EU Birds Directive as a Special Protection Area. A pSPA is a (SPA) site being considered at European level for designation as an SPA. Stakeholder Any individual or groups of people who are affected by, or have interest in, the activities and/or outcome of the BP Clair Ridge project.
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Abbreviations and Glossaries
Submerged Turret Loading The STL system consists of a conventional cargo tanker which connects/disconnects to a (STL) buoy offloading submerged turret buoy and flexible riser, which in turn are catenary moored to piled anchors. Suction anchor Type of anchor that is partly hollow inside. When installed the hollow part of the suction anchor sinks into the seabed. The suction anchor is then closed, creating a vacuum inside the anchor. Tandem offloading A commonly used method in offloading from the stern of the offloading vessel to the bow of the loading vessel. Temporary Threshold Shift A temporary decrease in hearing sensitivity caused by exposure to loud noise. (TTS) Thermocline Oceanic water layer in which water temperature decreases rapidly with increasing depth. Thruster A propulsive device used by vessels for station keeping, attitude control, or long duration low acceleration. Topsides Describes the equipment situated on a platform including, for example, the oil production plant, accommodation block and drilling rig Torque and Drag Torque is the tendency of a force to rotate an object about its axis, while Drag is the force that opposes the relative motion of an object through a liquid. Trawling Method of fishing in which a large bag-shaped net is dragged or trawled. Mouth of the bag is kept open by a variety of methods including wooden beams (beam trawl) or a large flat (otter) board (otter trawl). Tree Assembly of valves and fittings to control the flow of oil and gas from the well. Umbilical Any of various external electrical lines or fluid tubes which connect one portion of a system to another. Vessel Integral This system helps in coalescing water droplet in a separator and increasing the size of the Electrostatic Coalescer water droplet. (VIEC) Venting Discharging of un-burnt, unwanted gases or hydrocarbons which, due to temporary malfunction or maintenance of process plant, cannot be safely stored or retained in process vessels. Viscosity The resistance of flow of a liquid. Water Injector This refers to the method in oil industry where water is injected back into the reservoir, usually to increase pressure and thereby stimulate production. Well clean up Leaving the well bore clean after drilling by displacing mud and cuttings to bring on production Well completion The work of preparing a newly drilled well for production, including cementing, xmas tree deployment and erecting flow tanks. Wellhead A top of casing and the attached control and flow valves. The wellhead is where the control valves, testing equipment and take-off piping are located. Well testing Testing in an exploration or appraisal well is directed at estimating of reserves in communication with that well, in addition to well productivity. Testing in a production well also monitors the effects of cumulative production on the formation. Workover A maintenance job on a well, usually to replace equipment or stimulate production.
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Abbreviations and Glossaries
Well intervention This is any operation carried out on oil or gas well during, or at the end of its productive life, that alters the state of the well and or well geometry that provides well diagnostics and manages the production of the well. Y piece Used to split a single connection into two. Zooplankton Animals that drift in the plankton, mostly microscopic.
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November 2010
Abbreviations and Glossaries
Glossary of Latin Names
Common name
Latin name hippoglossoides
Common name
Latin name
Atlantic puffin Fratercula arctic Arctic skua Stercorarius parasiticus Arctic tern Sterna paradisaea Basking shark Cetorhinus maximus Black-legged kittiwake Rissa tridactyla Black guillemot Cepphus grylle Bearded seal Erignathus barbatus Barnacle goose Branta leucopsis Blonde ray Raja brackyura Blue fin tuna Thunnus thynnus Blue whale Balaenoptera musculus Blue-whiting Micromesistius poutassou Bottlenose dolphin Tursiops truncatus Catfish Anarhichas lupus Cod Gadhus morhua Common dolphin Delphinus delphis Common guillemot Uria aalge Common sea urchin Echinus esculentus Common star fish Asterias rubins Conger eel Conger conger Cormorant Cepphus grylle Dab Limanda limanda Deepwater red crab Chaceon affinis Dogfish Scyliorhinus canicula Dunlin Calidris alpina European storm petrel Hydrobates pelagicus Great black-backed gull Larus marinus Great shearwater Puffinus gravis Great skua Catharacta skua Greater forkbeard Phycis blennoides Greater silver smelt Argentina silus Greenland halibut Reinhardtius
November 2010
Grey seal Halichoerus grypus Fin whale Balaenoptera physalus Haddock Melanogrammus aeglefinus Hake Merluccius merluccius Halibut Hippoglossus hippoglossus Harbour porpoise Phocoena phocoena Harbour seal Phoca vitulina Harp seal Phoca groenlandica Hen harrier Circus cyaneus Herring Clupea harengus Herring gull Larus argentatus Hooded seal Cystophora cristata Horse mackerel Trachurus trachurus Horse mussel Modiolus modiolus John dory Zeus faber Keel worm Pomatoceros triqueter Killer whale Orcinus orca Kittiwake Rissa tridactyla Leach’s petrel Oceanodroma leucorhoa Lemon sole Microstomas kitt Lesser black-backed Larus fuscus gull Long-tailed skua Stercorarius longicaudus Long-finned pilot whale Globicephala melas Little tern Sterna albifrons Ling Molva molva Mackerel Scomber scombrus Megrim Lepidorhombus whiffiagonis Monkfish Lophius spp Minke whale Balaenoptera acutorostrata, Northern fulmar Fulmarus glacialis Norway lobster Nephrops norvegicus Northern gannet Morus bassanus
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Abbreviations and Glossaries Common name
Latin name
Plaice Pleuronectes platessa Pollack Pollachius pollachius Pomarine skua Stercorarius pomarinus
Common name
Latin name
White-beaked dolphin Lagenorhynchus albirostris Witch
Glyptocephalus cynoglossus
Portuguese dogfish Centroscymnus coelolepis Porbeagle Lamna nasus Purple sandpiper Calidris maritima Razorbill Alca torda Ray’s bream Brama brama Red gurnard Aspitrigla cuculus Redfish Sebastes spp Red mullet Mullus surmuletus Red-necked phalarope Phalaropus lobatus Red-throated diver Gavia stellata Ringed plover Charadrius hiaticula Ringed seal Pusa hispida Risso’s dolphin Grampus griseus Saithe Pollachius virens Sea bream Spondyliosoma spp Sei whale
Balaenoptera borealis borealis
Shag Stercorarius parasiticus Short-eared owl Asio flammeus Shortfin mako shark Isurus oxyrinchus Sooty shearwater Puffinus griseus Sperm whale Physeter macrocephalus Spurdog Squalus acanthias Squat lobster Munida asrsi, M. rugosa Sturgeon Acipenser sturio Tope Galeorhinus galeus Torsk Brosme brosme Turbot Scophthalmus maximus Turnstone Arenaria interpres Whimbrel Numenius phaeopus Whiting Merlangius merlangus
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November 2010
Contents 4.4
Seabed sediments ................................... 4.5
4.5
Benthic communities.............................. 4.12
Standard Information Sheet........................ i Non-Technical Summary ........................... iii
4.6
Plankton and primary production ........... 4.14
4.7
Fish populations..................................... 4.17
Introduction............................................................iii
4.8
Seabirds................................................. 4.21
The development.................................................. vi
4.9
Marine mammals ................................... 4.27
The environment................................................... xi
4.10 Commercial fisheries ............................. 4.31
Assessment of potential impacts..........................xii
4.11 Other sea users ..................................... 4.35
The way forward ..................................................xix
4.12 Conservation interest............................. 4.39
Contents
Abbreviations...........................................xxi Glossary ............................................... xxvii Glossary of Latin Names ...................... xxxv Contents ..............................................xxxvii 1 Introduction..................................... 1.1 1.1
Project background and purpose ............. 1.1
1.2
Regulatory context ................................... 1.6
1.3
BP environmental policy and requirements1.6
1.4
Aim of the EIA process and scope of the environmental statement.......................... 1.8
2
Alternatives..................................... 2.1 2.1
Introduction............................................... 2.1
2.2
Basis for the Quad204 Project ................. 2.3
2.3
Concept selection..................................... 2.3
2.4
Concept definition .................................... 2.8
2.5
Decisions remaining to be made and future options..........................................2.21
5
The Environmental Impact Assessment Process ...................... 5.1 5.1
Overview .................................................. 5.1
5.2
Environmental screening ......................... 5.1
5.3
Scoping and consultation......................... 5.2
5.4
Environmental issues identification (ENVID).................................................... 5.9
5.5
EIA methodology ..................................... 5.9
5.6
Assessment of residual impacts ............ 5.13
5.7
EIA integration with overall environmental management .......................................... 5.13
6
Physical Presence .......................... 6.1 6.1
Seabed impacts ....................................... 6.1
6.2
Interaction with other sea users............... 6.7
7
Discharges to Sea .......................... 7.1 7.1
Introduction .............................................. 7.1
7.2
Regulatory control.................................... 7.1
The Development ........................... 3.1
7.3
Drilling discharges ................................... 7.2
3.1
Fields and reservoirs................................ 3.1
7.4
Installation and commissioning discharges7.10
3.2
Wells and drilling ...................................... 3.2
7.5
Operational discharges.......................... 7.11
3.3
Production overview.................................3.6
7.6
Cumulative and transboundary impacts 7.16
3.4
Subsea infrastructure .............................3.11
3.5
Disconnection and reconnection of existing subsea infrastructure ................3.16
8.1
Introduction .............................................. 8.1
8.2
Regulatory control.................................... 8.1
3.6
Floating Production Storage and Offloading (FPSO) vessel ......................3.16
8.3
Marine mammals in the Quad204 Project area.......................................................... 8.2
3.7
Decommissioning...................................3.28
8.4
Noise sources and potential impacts....... 8.3
The Environment ............................ 4.1
8.5
Noise modelling and potential impact...... 8.6
4.1
Introduction............................................... 4.1
8.6
Management and mitigation measures . 8.13
4.2
Hydrology .................................................4.1
8.7
Residual impacts ................................... 8.14
4.3
Meteorology..............................................4.4
8.8
Cumulative and transboundary impacts 8.15
3
4
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8
Underwater Noise ........................... 8.1
Page xxxvii
Contents 8.9
9
European protected species (EPS) risk assessment ............................................8.16
Atmospheric Emissions...................9.1 9.1
Introduction...............................................9.1
9.2
Regulatory control ....................................9.2
9.3
Sources of potential impact (emissions quantification) ...........................................9.3
9.4
Management and mitigation .....................9.9
9.5
Residual impacts ....................................9.10
9.6
Cumulative and transboundary Impacts.9.15
10
Accidental Events .........................10.1
13.3 Issues removed or reduced by design ... 13.2 13.4 Key residual issues ................................ 13.2 13.5 Cumulative and transboundary impacts 13.2 13.6 Protected areas and species ................. 13.3 13.7 Environmental management .................. 13.3 13.8 Final remarks ......................................... 13.3
14
References....................................14.1
Appendix A Appendix B
10.1 Introduction.............................................10.1 10.2 Regulatory control ..................................10.1
Appendix C
10.3 Oil spills ..................................................10.2 10.4 Behaviour of oil at sea ..........................10.10 10.5 Environmental vulnerability to oil spill...10.16 10.6 Residual risks .......................................10.26 10.7 Oil spill response strategy ....................10.26
Appendix D Appendix E Appendix F Appendix G
10.8 Cumulative and transboundary risk......10.27 10.9 Cumulative risk .....................................10.27 10.10 Transboundary risk...............................10.28
Appendix H
Summary of Environmental Legislation Environmental Performance Requirements Schiehallion and Loyal Forecast Production Data EIA Matrices Commitments Register Summary of the DREAM Model Atmospheric Emissions Quantification Data Summary of Atmospheric Dispersion Model ADMS4
10.11 Chemical spills......................................10.28
11
Waste............................................11.1
11.1 Introduction.............................................11.1 11.2 Regulatory control ..................................11.1 11.3 Waste management policy .....................11.2 11.4 Waste generation ...................................11.2 11.5 Quad204 waste management strategy ..11.4
12
Environmental Management .........12.1
12.1 Quad204 Project environmental management and commitments .............12.1 12.2 The BP environmental management process ...................................................12.2 12.3 Environmentally critical equipment.........12.3 12.4 Environmental monitoring.......................12.3 12.5 Environmental awareness and training ..12.4 12.6 Interface with contractors .......................12.4
13
Conclusions ..................................13.1
13.1 Approach ................................................13.1 13.2 Potential environmental issues...............13.1 Page xxxviii
November 2010
Introduction
1
Introduction
This chapter explains the background and purpose of the proposed Quad204 Project and describes the aim and scope of the environmental impact assessment (EIA) process carried out. The underlying regulatory and BP environmental requirements are also outlined. This Environmental Statement (ES) presents the findings of the environmental impact assessment (EIA) conducted by BP for the proposed Quad204 Project. The project involves the redevelopment of the existing Schiehallion and Loyal fields. This includes new surface production facilities with the replacement of the existing Schiehallion Floating Production Storage and Offloading (FPSO) vessel with a new Quad204 FPSO, new production and water injection wells and additional subsea infrastructure to access the remaining hydrocarbon resources in the Schiehallion and Loyal reservoirs. The project is located within Quadrants 204 and 205 of the United Kingdom Continental Shelf (UKCS) in water depths of 350 to 500 m on the slope of the Faroe-Shetland channel (Figure 1.1). Approximate distances from the Quad204 FPSO to various landmarks and boundaries are also provided in Figure 1.1.
1.1
Project background and purpose
1.1.1
History of the Schiehallion/Loyal field development
The Schiehallion field was discovered in late 1993 by well 204/20-1 and sidetrack 204/20-1z. The Loyal field was subsequently discovered in 1994 by well 204/20-3. Both fields have been developed using subsea wells tied back to the internal turretmoored Schiehallion FPSO. The fields have been in production since 1998 and have produced approximately 55.6 million cubic metres (ca. 350 million barrels) of oil and 4.6 billion standard cubic metres (ca. 163 billion standard cubic feet) of gas to the end of 2009. The Schiehallion and Loyal fields are owned by different partner groups (Table 1.1). BP is the nominated operator of the Schiehallion/Loyal field development partnership including the Schiehallion FPSO and subsequent replacement Quad204 FPSO.
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Schiehallion Licences Field Interest Owner
Field Interest %
BP Exploration Operating Company Limited
33.35
Shell U.K. Limited
33.35
Hess Limited
15.67
Statoil (U.K.) Limited
5.88
OMV (U.K.) Limited
5.88
Murphy Petroleum Limited
5.88
Loyal Licence Field Interest Owner
Field Interest %
BP Exploration Operating Company Limited
50
Shell U.K. Limited
50
Table 1.1: Project partners and field ownership interests
The appraisal of the Schiehallion field, which consisted of 4 wells drilled in 1994, was undertaken in two phases: h Early appraisal wells to understand volume of oil h Later appraisal wells to understand and reduce uncertainties An extended well test was undertaken on a horizontal appraisal well in 1995. At sanction, the Schiehallion and Loyal fields were to be developed with 12 production wells, 10 water injection wells and a gas disposal well, bringing the total number of wells to 23 (Phase 1). First oil was delivered as planned in July 1998. By the end of the first year of production, 19 of the planned 23 development wells had been drilled. However, shortly after first oil was delivered it was discovered that production targets would not be met. This resulted in the production target being revised down in 1999.
Page 1.1
Introduction
Figure 1.1: Location of the Quad204 Project Project background and purpose
The initial phase of the Schiehallion/Loyal field Page 1.2
development was analysed and it was concluded that remedial action was necessary in order to November 2010
Introduction meet anticipated life of field oil recovery. As a result three additional phases of drilling were undertaken:
drill centre.
h In 1999 a 3 well programme was sanctioned (referred to as Phase 2a) that consisted of 1 production well, 1 water injection well and 1 appraisal well. The wells were drilled and brought online between 2000 and 2001. h In 2000 another 3 well programme was sanctioned (referred to as Phase 2b) that consisted of 1 production well and 2 water injection wells. The wells were drilled between 2001 and 2002 and the production well and 1 water injection well were brought online during this period. h In 2001 an 8 well programme was sanctioned (referred to as Phase 3) that consisted of 3 production wells, 4 water injection wells and a pilot hole. The wells were drilled and brought online between 2002 and 2003. The 2001 study also defined the need for a new dedicated drill centre for the Claw area of the Schiehallion field. This requirement formed the basis of the Phase 4 development. The proposal was to create a new drill centre at Claw (an area approximately 6 km to the west of the existing Schiehallion FPSO) with 5 wells tied back to the Schiehallion FPSO for processing and export. In 2002 the well programme was sanctioned. The development options for Phase 4 were reevaluated following unexpected drilling results which indicated larger than expected gas volumes. The gas handling constraints on the Schiehallion FPSO resulted in this proposed development being abandoned. The Claw reservoir will be developed as part of the Quad204 Project but not from a Claw
In 2003 an appraisal well was drilled to assess further field potential north of the area of the field already under development. In 2006 the Phase 5 development wells referred to as the North West Area Development (NWAD) were drilled. This consisted of 1 multi-lateral production well and 2 injection wells which were drilled from a new drill centre. The subsea infrastructure for this development was installed in 2007. However, due to essential maintenance and integrity work on the Schiehallion FPSO, topsides modifications to permit production and injection from these wells was only completed in mid 2009. In 2004 a further 2 wells were sanctioned (referred to as Segment 4 T25) and these were drilled and brought online in 2005. An additional 4 well programme (referred to as T20s and T30s Infill) was developed in 2004. However, only 2 of these wells were drilled and brought online in 2005. To date the total well stock comprises 54 wells: 22 production wells (2 of which originate from a single multi-lateral well) and 23 water injection wells at Schiehallion, 4 production wells and 4 water injection wells at Loyal, and a gas disposal well at An Teallach.
1.1.2
Environmental impact assessments undertaken
Table 1.2 provides a summary of the EIAs undertaken and Environmental Statements produced for the Schiehallion/Loyal field development since field discovery. The Phase I EIAs were undertaken as part of BP’s environmental policy prior to the statutory requirement for an EIA. The Schiehallion Phase 3
Phase
Drilling period
Environmental impact assessment / environmental statement
Date
Phase 1
1996 - 2000
Schiehallion Field Development Stage I Environmental Assessment (pre-statutory)
March 1996
Schiehallion Field Development Stage II Environmental Assessment (pre-statutory)
August 1997
Phase 2
2000 - 2002
N/A
Phase 3
2002 - 2003
Schiehallion Phase III Development Environmental Statement for Offshore Activity
September 2001
Phase 4
2003
Schiehallion Phase 4 Development Environmental Statement
May 2002
Phase 5
2003 – 2007
Schiehallion Development Wider Field Perspective Environmental Statement
May 2004
Table 1.2: Environmental impact assessments undertaken and environmental statements produced for the Schiehallion/Loyal field development to date
November 2010
Page 1.3
Introduction development did not meet the standard criteria for which an ES is normally required. However, following consultation with the Department of Trade and Industry (DTI) at the time, regarding the area’s environmental sensitivity, BP’s future plans and the cumulative effects of developments west of Shetland, the DTI requested the submission of an ES. Phases 4 and 5 were undertaken as a requirement of the Offshore Petroleum Production and Pipelines (Assessment of Environmental Effects) Regulations 1999 (as amended).
1.1.3
Basis for the Quad204 Project
The existing Schiehallion/Loyal field development comprises five drill centres with a total current well stock of 54 wells, an extensive subsea infrastructure system and the Schiehallion FPSO. Gas is exported via the West of Shetland Pipeline System (WOSPS) to the Sullom Voe Terminal
(SVT) in Shetland. Oil is exported via shuttle tanker to SVT. Production history, seismic survey data and recent reservoir studies have confirmed that significant oil potential still remains to be extracted from the Schiehallion and Loyal fields. In order to develop the remaining reserves fully the existing FPSO would need to remain on-station until 2045. In recent years operating challenges on the Schiehallion FPSO have resulted in a deterioration of the production operating efficiency and the existing vessel is unable to fulfil the processing requirements of the anticipated economic field life. Redevelopment of the surface production facilities, new wells and additional subsea infrastructure are therefore required to access the remaining hydrocarbon resources. Additionally, a number of oil and gas discoveries and exploration prospects exist in the area which
Figure 1.2: Fields and prospects in the Quad 204 area
Page 1.4
November 2010
Introduction could potentially be developed in the future by subsea tie-back to the Quad204 FPSO (Figure 1.2). Several concepts were considered for the Quad204 Project and these are described briefly in Section 1.1.4 and in more detail in Chapter 2 of this ES. An indicative project schedule is presented in Figure 1.3. The proposed timing of activities may change during project development. The current planned schedule is for the project sanction decision to be made in the first quarter (Q1) of 2011. Removal of the existing FPSO is planned for Q3 2014. The new FPSO is scheduled to be onstation in Q1 2015 with first oil in Q4 2015.
1.1.4
Project concepts
BP and its Partners evaluated a range of potential development schemes for the Quad204 Project (described in detail in Chapter 2). These included:
h New Semi-Submersible development During the concept selection process an environmental comparative assessment and Best Available Techniques (BAT) assessment was undertaken of the different options. The environmental screening focused on the risks and opportunities of each option and the results were fed into the overall concept selection process, which included consideration of health and safety, environmental impact, cost and value, strategic benefit, technical feasibility, field life operability and deliverability. The selected development concept for the Quad204 Project agreed by the Partners was the installation of a new internal turret-moored FPSO at the same location as the existing Schiehallion FPSO (see Figure 1.5). This option performed best against all the selection criteria. The selected project concept is described further in Chapter 3.
h Maintenance and upgrade of the existing Schiehallion FPSO in-situ h Disconnection and tow of the Schiehallion FPSO to dry dock for modification and upgrade h New FPSO development h Subsea tie-backs to a new steel platform further up the continental shelf h New Tension Leg Platform (TLP)
Figure 1.3: Indicative schedule for the Quad204 Project
November 2010
Page 1.5
Introduction
1.2
Regulatory context
1.2.1
Requirement for an EIA
The EIA reported in this ES has been carried out in accordance with the requirements of the Offshore Petroleum Production and Pipelines (Assessment of Environmental Effects) Regulations 1999 (as amended). These regulations require the undertaking of an environmental assessment and production of an ES for certain types of offshore oil and gas project likely to have a significant effect on the environment. Approval of the ES is required before approval can be granted to the Field Development Plan under the Petroleum Act 1998. An EIA is mandatory for any development that is expected to increase production by more than 500 tonnes (ca. 3.1 mbd) of oil per day and more than 3 500,000 sm (ca. 17.4 mmscf) of gas per day. The Quad204 Project, as a continued development of the Schiehallion and Loyal fields, is expected to see increases in production levels that exceed these threshold quantities, therefore an EIA is required. BP internal management processes also require that an EIA be undertaken for projects such as Quad204. The undertaking of the EIA has ensured that all of the potential impacts from the project have been considered and that a full consultation exercise with external stakeholders is undertaken.
1.2.2
Key environmental legislation
The Quad204 Project will be subject to the requirements of UK and EU legislation in addition to other international treaties and agreements such as the Oslo and Paris Commission (OSPAR). As the development lies outwith UK territorial waters (i.e. more than 12 nm from land), the majority of the activities undertaken will be governed under the applicable legislation regarding offshore oil and gas activities, rather than that governing inshore waters. The key environmental legislation applicable to the Quad204 Project is listed below and summarised in Appendix A. h Petroleum Act 1998 h Coast Protection Act 1949 h Petroleum Licensing (Production) (Seaward Areas) Regulations 2008 h Food and Environment Protection Act 1985
h Offshore Combustion Installations (Prevention and Control of Pollution) Regulations 2001 h Offshore Chemical Regulations 2002 h Offshore Petroleum Activities (Conservation of Habitats) Regulations 2001 (as amended) h Offshore Marine Conservation (Natural Habitats &c.) Regulations 2007 h Merchant Shipping (Prevention of Pollution by Sewage and Garbage from Ships) Regulations 2008 h Oil Pollution Preparedness, Response and Cooperation Convention Regulations 1998 h Offshore Installations (Emergency Pollution Control) Regulations 2002 In addition, key legislation and guidance relating to the main environmental issues associated with the project are presented in Chapters 6 to 11 of the ES. For example, EU Emissions Trading Scheme (ETS) requirements are described in Chapter 9 Atmospheric Emissions.
1.2.3
Evolving environmental legislation
BP recognises that environmental legislation is subject to change as technology advances and understanding of the impacts of human activities on the environment develops. Therefore, an important factor throughout the EIA process has been the consideration of both known evolving legislation and other potential future regulation. A Future Legislation Review was conducted to provide an overview of current and evolving UK environmental legislation that has implications for the design of the Quad204 Project and that should be considered as part of the detailed design process. Potential future legislative changes of relevance to the EIA are described in the appropriate ES chapter.
1.3
BP environmental policy and requirements
BP and its Partners are committed to conducting activities in compliance with all applicable legislation and in a manner which contributes to BP’s stated goals of “no accidents, no harm to people and no damage to the environment”. In order to achieve these goals there is a hierarchy of common policies, commitments and expectations that identify policy and regulatory requirements and provide tools to assist in compliance and performance improvements.
h Offshore Petroleum Activities (Oil Pollution Prevention and Control) Regulations 2005 Page 1.6
November 2010
Introduction
Figure 1.4: BP North Sea SPU HSE Policy
November 2010
Page 1.7
Introduction In addition to relevant UK and EU legislation and international standards, the Quad204 Project is subject to the following BP environmental requirements: h BP North Sea Strategic Performance Unit (SPU) HSE policy (Figure 1.4) h BP Group Defined Practice (GDP) on Environment (Section 12.1) h Quad204 Project Environmental Performance Requirements (Appendix B) These requirements, together with applicable legislation, have been applied from the start of the Quad204 Project, informing the concept selection and early design processes with the aim of eliminating or limiting environmental impact by design. During operations, the Quad204 development will conform to the requirements of the environmental management system (EMS) established for the BP North Sea SPU, which is certified to ISO 14001 (see Section 12.2). Details of BP’s environmental policy and management processes, and how they will be applied to the Quad204 Project and implemented during the operational phase, are provided in Chapter 12.
1.4
Aim of the EIA process and scope of the environmental statement
The aim of the EIA process is to assess the potential environmental impacts that may arise from the proposed Quad204 Project and identify measures that will be put in place to prevent or minimise these impacts. The EIA process is integral to the project, assessing potential impacts and setting design and operational challenges to ensure that the residual impacts of the project are minimal. The process also provides for the concerns of stakeholders to be identified and addressed as far as possible at an early stage, and ensures that the planned activities comply with environmental legislative requirements and with BP’s environmental policy. The ES is a report summarising the EIA process and outcomes. It also includes details of how the project decision-making was undertaken and how environmental criteria were incorporated into that process. The scope of the EIA was developed and agreed with the Department of Energy and Climate Change (DECC) during the scoping consultation process (see Chapter 5). The ES is submitted to DECC to inform the decision on whether or not the Page 1.8
project may proceed, based on the acceptability or otherwise of the residual levels of impact, and is subject to formal public consultation. Based on guidance from DECC, this ES has addressed the following elements of the Quad204 Project: h Installation, hook-up and commissioning, and the presence of new subsea infrastructure and a new FPSO at the existing FPSO location h Continued production of the Schiehallion and Loyal fields through the new FPSO including fluids processing and export and subsea activities h Drilling of new wells via mobile drilling rigs h Decommissioning The assessment has included both routine and abnormal events (such as production upsets) and considered the risk of accidental events with possible environmental implications. This ES has also addressed the future operational life of the Schiehallion and Loyal fields as far as practicable. This includes consideration of future drilling operations, future subsea infrastructure and ongoing production and operation of the new FPSO. Future satellite areas are considered in terms of their cumulative impacts rather than a detailed assessment, and the ES has reported any survey requirements as appropriate for new satellites. Based on DECC guidance this ES does not include the disconnection of the existing FPSO (including temporary suspension of well and production operations) or tow away and sale or disposal of the existing FPSO. These activities will be addressed through BP’s environmental policy and management processes as appropriate. Although the scope does not include the disconnection of the existing FPSO, this ES describes, at a high level, the elements of the disconnection process in order to clarify the reconnection/installation of the new FPSO. Other project elements not addressed within this ES are: h Existing well, subsea and pipeline infrastructure h Any modifications at SVT that may be required as a result of receiving, storing and exporting fluids from the new FPSO h Fabrication of the new FPSO and new subsea infrastructure The potential development of the Alligin field as a subsea tie-back to the Quad204 FPSO is a November 2010
Introduction separate project and is not part of this ES. However, for reference the location of the Alligin field has been included on location figures as appropriate (Figures 3.7 and 4.5). It has been agreed with DECC that if the Alligin field is developed an addendum to the Quad204 Project ES will be produced at the appropriate time. A polymer flood enhanced oil recovery (EOR) scheme as part of the Quad204 Project could potentially increase the field recovery factor, and this option is currently being evaluated. If EOR is implemented an addendum will be made to this ES at the appropriate time, if required. It should be noted that environmental considerations have been included in the Quad204 decision-making process from the outset, from concept selection, through Front End Engineering Design (FEED) and will continue into detailed design (see Section 2.1.1). Decisions to reduce environmental impact from the Quad204 Project are reported throughout this ES. This ES reports the outcome of the EIA process and includes the following: h A non-technical summary of the whole ES h Justification for the project and the role of the EIA (Chapter 1) h Description of the options considered for the project and how environmental considerations were integrated into the decision-making process (Chapter 2) h Description of the selected concept (Chapter 3) h Description of the environment in the vicinity of the project and the key environmental sensitivities (Chapter 4) h Methods used to identify and evaluate the environmental issues associated with the project and the informal consultation undertaken to date (Chapter 5) h Detailed assessment of each issue, including the potential for any cumulative or transboundary impacts (Chapters 6 to 11) h Environmental management and control measures that will be in place during the project (Chapter 12) h Conclusions (Chapter 13) h References (Chapter 14)
November 2010
Page 1.9
Introduction
This page has been deliberately left blank
Page 1.10
November 2010
Introduction
Figure 1.5: Quad204 Project development concept (not to scale: for illustrative purposes only)
November 2010
Page 1.11
Introduction
This page has been deliberately left blank
Page 1.12
November 2010
Alternatives
2
Alternatives
This chapter describes the decision-making process applied by the Quad204 Project and outlines the main options considered for the project at both the conceptual and Front End Engineering Design (FEED) stages. The decisions made have resulted in the removal or major reduction by design of several sources of potential environmental impact.
2.1
Introduction
The EIA Directive (85/337/EEC) requires that “where appropriate, an outline of the main alternatives studied by a developer and an indication of the main reasons for choice, taking into account the environmental effects” be provided. DECC guidance notes on the Offshore Petroleum Production and Pipelines (Assessment of Environmental Effects) Regulations 1999 (DECC, 2009a) require that “the ES should describe the main alternatives to the proposed activity that have been considered. The advantages and disadvantages of each option should be clearly stated with the specific environmental implications indicated for each. The main reasons for the selection of the preferred option should be described, taking into account the environmental effects. Other factors influencing the choice of alternatives should be noted e.g. feasibility, technical constraints and cost effectiveness. If a formal option appraisal has been carried out it
should be described and the relevant decision factors noted. Options such as alternative sites, timing, construction practices, plant and equipment, operating processes and pipeline routes should be considered where appropriate”.
2.1.1
The decision-making process
From the earliest stages of concept assessment, the Quad204 project team introduced an holistic process of option analysis in order to facilitate and document decisions in a transparent and objective way. The strength of the process is ensured through having the right people involved which enables experienced and multi-disciplined input to the decision-making process. Decision evaluation included analysis of seven factors to characterise the concept or technical options under consideration (Figure 2.1). This holistic approach ensured environmental considerations were on an equal footing to other factors such as health and safety, cost and value, and technical feasibility. Table 2.1 provides more detail on the evaluation criteria and Quad204 Project goals which were set at the start of the project. The decision-making process has been applied by the Quad204 Project during concept selection and Front End Engineering Design (FEED) and will continue into detailed design after project sanction. The decisions taken to date are typically crossdiscipline, with high impact, and where transparency was considered essential, i.e. for DECC, Health and Safety Executive (HSE), partners and external stakeholders.
Figure 2.1: Decision-making process
November 2010
Page 2.1
Alternatives Evaluation criteria Health and Safety
Quad204 Project goals No harm to people
Options will include “zero hazard” option
Improve on current best industry performance
Use safety factor as checklist to evaluate each option
Anticipate impact of future legislation Zero-based Hazard Management
Environment
Identify preferred option(s)
Assess size, likelihood of hazards and management options
Set hazard management measures and requirements for selected option(s)
No damage to the environment
Start from zero emissions
Minimise emissions and waste generation
Environmental impact
Maximise efficiency of resource and energy use
Cost per tonne figures for emissions
Avoid significant or irreversible biodiversity impact
Analysis of damage and recovery times for environmental receptors
Anticipate future legislation
Cost and Value
Issues to be considered
Improve on current industry best performance
Benchmarking against current projects to test for “better than” criteria
Implement Environmental Impact Management Process and Environmental Performance Requirements (EPRs)
Compliance with EPRs
Partnership desire to maximise NPV
Cost and schedule estimates, risks and uncertainty
Optimise capital efficiency
Optimisation of drilling programme
Optimise reserves recovery
Realize maximum value for existing vessel Life cycle costing
Strategic
Alignment with partner agreed Quad 204 Project opportunity statement and goals Transform Schiehallion area into top quality business with a long term future
Secure the Schiehallion and Loyal base Line of sight to 800 mmboe for Schiehallion (partnership agreed aspiration) Position to access the wider Quad 204 potential
Create a technology plan to enable enhanced recovery of the resource base in the area Align partnership to operate under a commercial framework which will bring the resources forward, protecting value for individual owners Field Life Operability
Technical
Deliverability
Facility designed to meet field life expectations for Schiehallion and Loyal
Operations / maintenance philosophies
Operating efficiency >90% through field life
Ramp-up and first year operability achieved
Deliver facilities with good operability and maintainability throughout life of sanctioned resources
Logistics
Facility designed to meet field life expectations for Schiehallion and Loyal
Sparing
Design simplicity Technology stretch / track record
Operating efficiency >90% through field life
Weight and footprint
Fit for purpose and simple design preferably using proven technology which is deliverable
Technical integrity Inherent flexibility
Any departures from proven technology or technology which has a history of delivery need to be fully understood and justified
Intervention / criticality
Delivery of the technology plan to enable enhanced recovery of the resource base in the area
System interfaces Engineering-based judgment
Able under the prevailing conditions to deliver the project ensuring that it meets the other 6 criteria
Acceptability to Regulators (HSE, DTI etc.)
Able to manage the transition from current situation to future Operating asset will fully own the redevelopment project outcomes and acknowledge it as a success
Materials selection
Internal / external market conditions / risk to schedule Execution risks Reputation Partner alignment Social implications (jobs, impact on other users, etc.) The project will create and deliver a highly deliverable sanction plan Experience-based judgment
Table 2.1: Evaluation criteria and Quad204 Project goals
Page 2.2
November 2010
Alternatives
2.2
Basis for the Quad204 Project
The opportunity for redeveloping the Schiehallion and Loyal fields has arisen because of a number of factors, in particular: h Production from the fields is currently constrained and will continue to be constrained by the existing Schiehallion FPSO in its current form due to capacity and throughput limitations and low operating efficiency h There is the potential for further development by drilling additional wells at existing Schiehallion and Loyal drill centres that will accelerate production and improve recovery, provided there is a production facility in place with sufficient capacity and longevity to exploit this opportunity h There is the potential for development of additional satellite fields in the vicinity of the Schiehallion and Loyal fields h The existing FPSO on-station design life is 20 years therefore it is due to come off station in 2018. However, with existing production constraints, it is considered likely that there will still be remaining oil/gas reserves unrecovered by this date if there is no change to the statusquo of the existing FPSO h There is some risk that the FPSO may need to be dry-docked before 2018 if there is a build-up of maintenance and repair work that cannot be dealt with effectively offshore The decision was therefore made by BP and its partners to investigate the options available for redevelopment of the Schiehallion and Loyal fields, known as the Quad204 Project.
2.3
Concept selection
2.3.1
Concepts considered
A series of concept options were evaluated that fell into three broad categories: h Continue with the existing FPSO with minimal modifications undertaken offshore (Option A the Reference Case) h Bring the FPSO ashore with a refurbishment scope (Options B1, B2, B3)
varied according to the concept type and capacity. The SURF scope ranged from replacement of some risers and addition of flowlines to ensure production capacity requirements were met, to more complex schemes involving re-routing of flowlines to a new facility location and installation of new risers. A number of additional concepts were also considered, but were screened out at an early stage for a variety of reasons, in particular project economics, technical and environmental factors. These early options included: h A Floating Storage Unit (FSU) with the existing vessel (Option C2) This option involved installing a FSU a few kilometres from the existing vessel to provide additional storage and deck space which could be used for additional processing plant such as power generation and water handling. Although this option would provide further deck space it did not tackle the fundamental issues with the existing vessel and would have to include either ‘A’ or ‘B’ option upgrades to the existing vessel. Transfer of fluids and power between the two vessels, the cost of the FSU including the required subsea changes, the cost of upgrades on the existing vessel and the extra operating costs associated with two crews made this option unattractive so it was not progressed. h A subsea tie-back to a shelf platform (Option C3) This option involved building a shallow water fixed platform similar to Clair Phase 1, on the continental shelf approximately 20 km southeast of the Schiehallion field. Fluids would be pumped from the existing subsea infrastructure to the platform where they would be processed. The oil and gas would be transported to SVT by pipelines and the produced water and any further injection water would be returned to the fields. This option was not progressed for technical reasons as subsea pumping of this quantity of multi-phase fluids from deep to shallow water over this distance was seen as challenging and would require specialised pipeline and pumping systems. h A fully subsea development with pipeline export to shore (Option C6)
h Replace the FPSO with a new build facility (Options C1, C4, C5) All of the options (excluding the Reference Case) involved disconnecting the FPSO and a subsea, umbilical, riser and flowline (SURF) scope that
November 2010
Page 2.3
Alternatives Option
A: Reference Case (Existing FPSO)
B1: Minor Upgrades to Existing FPSO
B2: Full Upgrade to Existing FPSO
B3: New Topsides on Existing FPSO
C1: New Build FPSO
C4: New Build TLP with Drill Rig
C5: New Build SemiSub with Drill Rig
Scope
Repair undertaken to existing FPSO offshore
Move existing FPSO onshore for repair and minor upgrades Minimal work-scope Some offshore refurbishment
Move existing FPSO onshore for full repair and process upgrades
Move existing FPSO onshore for full hull repairs and replacement of process systems and topsides
New replacement FPSO
New tension legged platform (TLP) Installation technology to minimise production shutdown period
New semisubmersible platform
Process Upgrades
None
Focus on alleviating process bottlenecks while retaining existing process systems as far as possible
Installation technology to minimise production shutdown period Oil export via shuttle tanker
Oil export via twin buoys to shuttle tankers
Installation technology to minimise production shutdown period Oil export via twin buoys to shuttle tankers
Gas compression refurbishment
Replacement gas compression
New topsides (as per new build FPSO)
Full new topsides and process systems
Full new topsides and process systems
Full new topsides and process systems
Install 4th water injection pump
Install 4th water injection pump
New marine systems
Dry trees and drilling rig on TLP
Drilling rig on semisubmersible
Process enhancements undertaken offshore
Additional power generation
New process systems (as per new build FPSO)
New separation system
Replacement of some marine systems
New swivel Additional minor upgrades SURF Scope
No change
No change
Minimal scope
Moderate scope
Moderate scope
Major scope
Minimal scope
1 x 10” flowline
3 x 10” flowlines
3 x 10” flowlines
1 x 10” flowline
3 x replacement risers
3 x replacement risers
3 x replacement risers
New flowlines and flowline corridors from TLP to existing drill centres
New risers
New risers Production Shutdown Duration
None
21 months
30 months
32 months
17 months
Partial shutdown
18 months
Production Capacity
220 mbd
220 mbd
320 mbd
320 or 400 mbd
320 or 400 mbd
400 mbd
400 mbd
Well Programme
No further drilling assumed
Pre-drilling
Pre-drilling
Pre-drilling
Pre-drilling
No pre-drilling
Pre-drilling
25 infill wells
25 infill wells
25 infill wells
25 infill wells
27 infill wells
31 infill wells
Table 2.2: Summary of concepts considered for detailed evaluation
Page 2.4
November 2010
Alternatives
This option involved taking all the fluids from the fields and pumping them to SVT for separation, then pumping the produced water and any other required injection water back to the fields for injection. This would require several large pipelines to be laid between the fields and SVT and supply of a large amount of power from a new power station on Shetland. This option was not seen as feasible at the moment so was not progressed. The concepts that were considered for more detailed evaluation are summarised in Table 2.2.
2.3.2
Environmental comparative assessment of concept options
As part of the overall concept analysis and selection process (see Section 2.3.3), a detailed environmental comparative assessment of each of the options was undertaken using BP’s Environmental Performance Requirements (EPRs) as the basis. The EPRs provide design criteria for new projects and major modifications; and direction and guidance for continual improvement in existing facilities. The EPRs used for this assessment fell into 11 broad categories: h Air quality h Community disturbance h Drilling and wells h Energy efficiency h Environmental liability prevention h Flaring and venting h Marine mammals h Ozone depleting substances h Physical and ecological impacts h Resource use and waste h Water management Building on the EPRs, the Quad204 Project established a set of project specific EPRs (Appendix B). The Quad204 specific EPRs include some additional requirements over and above the BP Environment Group Defined Practice, for example, previous environmental commitments that were made by Schiehallion (e.g. the use of ‘fishing friendly’ subsea trees; Aurora, 2004) and statutory requirements such as EU Emissions Trading Scheme metering specifications. These agreed Quad204 EPRs have been used to inform the Quad204 concept engineering process and were used as the basis for the environmental assessment of the redevelopment concepts.
redevelopment concepts, an Environmental Issues Identification (ENVID) workshop was held with representatives from the Quad204 Project HSE and engineering teams (including topsides, marine, subsea and wells teams). The workshop was used to review the EPRs against the range of concepts under consideration, and identify where key differentiators existed. The selection of differentiators focused attention and effort on those aspects where significant environmental differences existed between options. The ENVID workshop then reviewed and ranked each option against each of the EPRs and the findings were summarised in a spreadsheet. Each option was scored with (1) representing the option with the greatest risk of not meeting the EPR and (5) the option with the greatest opportunity to comply with the EPR. Following the ENVID workshop, a number of supporting studies were undertaken to inform the final environmental assessment and to confirm/expand on the workshop findings, these included: h Emissions Quantification Study h BAT Justification Report It should be stressed that at the concept selection stage for the project, the comparative assessment focused on opportunities to remove/reduce environmental impacts and the key differentiators between options rather than being an assessment and comparison of all potential impacts. The outcome of the environmental comparative assessment is summarised in Table 2.3. The findings were fed into the overall analysis and decision-making process (Section 2.3.3). The top three options based on environmental assessment were: h Option B3 (new topsides on existing FPSO) – this was the preferred option due to re-use of the existing FPSO hull coupled with major opportunities for improved environmental performance in the topsides facilities h Option C1 (new build FPSO) – this option provided the full environmental improvement opportunity scope, although it required the use of resources (e.g. steel) for construction of a new FPSO hull h Option C4 (new build TLP) – as for the new build FPSO, although it did not afford the opportunity for VOC recovery during tanker offloading due to the required twin buoy system
To kick-off the environmental assessment of the
November 2010
Page 2.5
Alternatives Option A
Option B1
Option B2
Option B3
Option C4
Option C5
Reference Case (Existing FPSO)
Minor Upgrades to Existing FPSO
Full Upgrade to Existing FPSO
New Topsides on Existing FPSO
New Build FPSO (320 mbd capacity)
New Build FPSO (400 mbd capacity)
New Build TLP with Drill Rig
New Build Semi-Sub with Drill Rig
EPR-1 Air Quality
24%
24%
28%
92%
96%
92%
72%
72%
EPR-2 Community Disturbance
100%
100%
100%
100%
80%
80%
80%
80%
EPR-4 Drilling and Wells
55%
55%
50%
45%
50%
45%
70%
60%
EPR-5 Energy Efficiency
40%
40%
46%
80%
63%
80%
86%
80%
EPR-6 Environmental Liability Prevention
64%
48%
52%
52%
76%
76%
68%
68%
EPR-7 Flaring and Venting
20%
20%
45%
100%
100%
100%
90%
90%
EPR-8 Marine Mammals
60%
60%
60%
60%
53%
53%
60%
53%
EPR-9 Ozone Depleting Substances
60%
60%
60%
80%
80%
80%
80%
80%
EPR-10 Physical and Ecological Impacts
87%
87%
87%
87%
60%
60%
60%
60%
EPR-11 Resource Use and Waste
100%
100%
90%
80%
70%
60%
45%
50%
EPR-12 Water Management
20%
20%
75%
95%
95%
95%
95%
95%
Overall Score
57%
56%
63%
79%
75%
75%
73%
72%
Environmental Performance Requirement
Best
Option C1
> 80% 70 - 80%
Average
50 - 70% 30 - 50%
Worst
< 30%
Table 2.3: Outcome of the environmental comparative assessment
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2.3.3
Overall analysis of concept options
An assessment of each concept was undertaken using the holistic methodology described in Figure 2.1. Two inter-linked approaches to the concept evaluation were used: h Detailed evaluation of each option which drew on several pieces of work: h A concept safety assessment h A comparative environmental assessment including a BAT assessment of each option (Section 2.3.2) h Economic evaluation studies h Engineering and technical studies h A SWOT (strength, weakness, opportunity and threat) analysis that highlighted reasons for and against each option and associated risks h A summary of the construction and installation sequence to further assist identification of the risks to delivery in the context of the limited offshore construction weather window experienced West of Shetland h A matched pairs evaluation. This technique requires that each concept is compared with each of the other concepts on a sequential basis. A preferred concept is selected for each matched pair using the detailed evaluation above to make an informed choice. The concepts are ranked according to the frequency of selection. The comparison was made one evaluation factor at a time so a concept’s ranking for each factor is visible as well as its
overall ranking. The outcome of the matched pairs analysis is shown in Figure 2.2. It should be noted that value (project economics) was excluded from the matched pairs analysis and was evaluated separately due to its importance and because it can be used to eliminate some cases. The results of the overall comparative analysis (including environmental considerations) showed a clear preference for either a new build FPSO (Option C1) or new topsides on the existing refurbished hull (Option B3). The refurbishment and upgrade options performed poorly against the environmental, strategic and field life operability criteria and these options were rejected. Execution complexities are higher for the TLP and Semi-sub options, and this factor contributed strongly to these options also being rejected. Options C1 and B3 were carried forward for further evaluation, including a detailed assessment of value and economic risks and benefits, and the final decision on the development concept was a new build FPSO (Option C1) for the following reasons: h It was the best ranked option in terms of value h It was the best ranked option in terms of the six other criteria in the matched pairs analysis h A new build FPSO will have additional deck space available for expansion, allowing future 3rd party tie-backs and a potential enhanced oil recovery (EOR) scheme h A new build FPSO can provide a degree of mitigation against execution delays by allowing continued production and delayed disconnection of the existing FPSO h A new build FPSO has a shorter field shutdown
Figure 2.2: Matched pairs analysis
November 2010
Page 2.7
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period than the refurbishment options h Availability of ship-building yards are greater for a new hull and topsides than for new topsides alone h A new build FPSO meets the Quad204 Project objectives of optimising reservoir recovery and extending field life
2.4 Concept definition Following the selection of the preferred development concept as a new build FPSO, a number of other engineering design options were identified as part of the concept definition process during FEED. These options also underwent a holistic appraisal process as described in Figure 2.1. Those decisions which had environmental implications have been grouped into six areas: h Subsea infrastructure h FPSO hull design and station keeping h Oil and gas export h Liquid effluent handling h Gas handling and flare h Power generation The decisions are discussed in Sections 2.4.1 to 2.4.6 and an overview of the options is presented in Figure 2.3. The Quad204 Project is the redevelopment of the Schiehallion and Loyal fields. A major focus throughout the decision-making process has therefore been on incorporating lessons learned and opportunities for improvement from the existing Schiehallion FPSO to the design of the new Quad204 FPSO taking into consideration the operational experience gained and new technologies which have become available.
2.4.1
Subsea infrastructure decisions
Two inter-related decisions were made regarding subsea infrastructure: h Reuse or replacement of SURF infrastructure h Placement of the new FPSO in the existing or a new location The current design life for the subsea infrastructure at Schiehallion and Loyal is 20 years and theoretically ends in 2018 (Section 2.2). The Quad204 Project intends to extend the field life through to 2035 by replacing the existing FPSO with a new vessel. The key decision with respect to the existing SURF infrastructure is whether:
installed when the FPSO is replaced h Option 2 - The life of the existing systems can be extended through to 2035 through a combination of: h Appropriate inspection and trials to establish the current status h More effective integrity management over field life h Improved operational control h Replacement of equipment as required (i.e. later in field life) The final decision was for Option 2 - re-use of the existing subsea infrastructure and associated placement of the new FPSO at the existing location. This represented the best option by removing the health and safety and environmental issues associated with a major recovery and replacement of subsea equipment. This option was also seen to be the preferred option in terms of value.
2.4.2
FPSO hull design and station keeping decisions
Hull design The decision was made that the FPSO will be a relatively full hull form with a semi-elliptical bow and a full stern shape. This shape gives better performance in the West of Shetland environment than other FPSO shapes. There are two options for procuring an FPSO hull: h Option 1 - Use of a modified Suezmax tanker design complying with ship classification requirements h Option 2 - Modified tanker hull designed to classification society FPSO rules with specific local enhancements The final decision was for Option 2 - FPSO design with enhanced fatigue performance and corrosion resistance. Although this option involved higher capital expenditure (CAPEX) costs and had technical and deliverability issues regarding greater effort required for design, it was seen to be strategically attractive. This option also had the best safety and environmental performance through enabling an inherently safer design, fit for purpose for the West of Shetland environment.
h Option 1 - New equipment will need to be
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Figure 2.3: Summary of Quad204 Project development concepts and engineering decision process
November 2010
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Station keeping Two options were considered for station keeping of the FPSO: h Option 1 - Full passive weathervaning h Option 2 - Partial weathervaning with continuous thruster assistance Full passive weathervaning requires the placement of the turret at a position along the length of the FPSO that allows the vessel to naturally weathervane such that the mooring loads remain within design values in storm conditions, without thruster assistance. Thrusters in this option would only be required for heading control during offloading operations and would not be in continuous operation. Partial weathervaning enables the mooring system to be designed on the assumption that the vessel position will be maintained within prescribed limits by the use of the thrusters. The final decision was for Option 1 – full passive weathervaning. This is the environmentally preferred option due to reduced energy requirements and noise outputs. It also scored highly on safety grounds as it provides for an inherently safer design with no requirement for operation or maintenance of safety critical thruster systems. This option is also a
proven technical solution in the West of Shetland area and is the system in use at the existing Schiehallion FPSO.
2.4.3
Oil and gas export decisions
Gas from the Quad204 FPSO will be exported using the existing West of Shetland Pipeline System (WOSPS). Three options were considered for oil export from the FPSO: h Option 1 - Export by pipeline to SVT h Option 2 - Export by pipeline via Clair platform to SVT h Option 3 - Export by shuttle tankers to SVT or direct to market Table 2.4 summarises the output of the decisionmaking process for the oil export route The final decision was for Option 3 - oil export by shuttle tanker, as is currently undertaken for the Schiehallion FPSO. Oil offloading system Produced crude will be stored in cargo tanks and periodically exported by shuttle tanker. Tanker
Table 2.4: Decision-making process for oil export
November 2010
Page 2.11
Alternatives export requirements must meet two broad requirements: economic size of cargo export on each occasion and frequency of exports to ensure that production is not restricted through lack of storage space. To facilitate regular offloading of crude, the offloading system needs to be safely accessible in weather conditions experienced in the West of Shetland area. Four options were considered: h Option 1 - Side by side offloading h Option 2 - Tandem offloading h Option 3 - Catenary Anchor Leg Mooring (CALM) buoy offloading h Option 4 - Submerged Turret Loading (STL) buoy offloading The final decision was for Option 2 - tandem offloading, as is currently undertaken for the Schiehallion FPSO. Although there is some risk of oil spill from hose damage, this risk was seen to be less than side by side offloading and similar to the risks seen with either of the buoy options due to the complex emergency shut down (ESD) arrangements. Tandem offloading was also seen as the best value option as it can be used by most North Sea shuttle tankers and operation is possible in wave heights up to 5-6 m.
2.4.4
Liquid effluent handling decisions
Oil-water separation Three options were considered for oil-water separation: h Option 1 - Gravity separation h Option 2 - Cyclonic or centrifugal separation h Option 3 - Coalescence (electrostatic, chemical or physical) The decision was made that primary oil-water separation on the Quad204 FPSO will be by gravity separation (Option 1). Gravity separation with extended residence time was assessed to be the optimal solution for Quad204 given the high volumes of water experienced at the Schiehallion and Loyal fields. Gravity separation equipment was also seen to be strategically suitable as it allows for future enhancements to be applied where needed. In addition to gravity separation, compact electrostatic coalescers (CECs) will be installed upstream of the cargo oil tanks. Coalescers work by increasing oil droplet size thereby enhancing the performance of primary separation. Following a testing programme at FPSO start-up, the CECs should provide the opportunity to export crude oil Page 2.12
direct to market during the life of the Quad204 FPSO. One potential future enhancement is to install a vessel integral electrostatic coalescer (VIEC) at a later date. VIEC is a relatively new technology and it is anticipated that it could add considerable benefits to enhancing water-oil separation, in particular when water cuts increase further (>65%). Pilot trials are being conducted on the Schiehallion FPSO and operating experience from this will be used to make a final decision on its applicability for Quad204. Produced water disposal Produced water comprises original formation water plus increasing quantities of injection water as breakthrough increases with field life. Water volumes being produced from the Schiehallion and Loyal fields after 12 years of production are high (currently 40% water) and will increase further through field life. Two options were considered for disposal: h Option 1 - Reinjection of produced water to the reservoirs as base case h Option 2 - Overboard disposal of produced water (with seawater only injection for reservoir support) The Oslo and Paris Convention on the Protection of the Marine Environment of the North East Atlantic 1992 (OSPAR) is the cornerstone for UK regulation on produced water. OSPAR Recommendation 2001/1 for the Management of Produced Water from Offshore Installations requires that the base case for any new development is zero discharge of produced water. Moving away from this position requires demonstration/justification to DECC. In addition, OSPAR has a target for “zero harmful” discharge of produced water by 2020. Work is ongoing to identify a way forward on the definition of "harmful" and regulatory requirements to meet the OSPAR target. OSPAR is looking into a new Risk Based Approach in relation to the discharge of produced water. BP corporate policy embedded in the EPRs also requires new developments to take the reinjection of produced water as the base case. Moving away from this would require strong technical justification. Table 2.5 summarises the decision-making process for produced water disposal. Although more technically challenging than overboard disposal, Option 1 - produced water reinjection was selected as the base case for environmental, regulatory, BP policy and strategic reasons.
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Table 2.5: Decision-making process for produced water disposal
For reservoir support purposes however, there is not sufficient produced water volumes to fully cover water injection requirements, therefore produced water will be co-mingled with supplementary seawater. It should be noted that it will be possible to reinject produced water when seawater is unavailable, which is an improvement in availability to that seen on the existing Schiehallion FPSO. Produced water reinjection availability Three options were considered for produced water reinjection availability: h Option 1 - 95% PWRI availability which meets DECC and BP requirements h Option 2 - 98% PWRI availability which represents the Quad204 EPR stretch target h Option 3 - 99% PWRI availability A dispersed oil in produced water to sea trading system was previously in place in the UK and administered by DECC. This system has however been withdrawn. Nevertheless the Quad204 Project considered the cost of such a trading scheme in its evaluation of PWRI availability as there is no firm guarantee that such a scheme will not be reintroduced.
November 2010
Table 2.6 summarises the output of the decisionmaking process for the PWRI availability specification. The final decision was for a minimum availability specification of 95% (Option 1) with a target of up to 98% availability. Produced water handling when PWRI is unavailable The PWRI system will be designed to a high availability, but there will still be occasions when PWRI is not available. When PWRI is not available for short periods, a dedicated storage tank can be used for short-term storage; however, this is not an option for extended periods. Three options were considered for produced water handling in the event of extended PWRI unavailability: h Option 1 - Provision of dedicated (long-term) buffer storage h Option 2 - Production shutdown h Option 3 - Overboard discharge Dedicated long-term storage and production shutdown are the optimal options for environmental and strategic reasons but both incur significant CAPEX and production costs. Production shut-down also requires more frequent production system restarts and the associated operational issues. The selected option was therefore Option 3 - overboard Page 2.13
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Table 2.6: Decision-making process for PWRI availability
discharge of produced water, when PWRI is unavailable for extended periods. The Schiehallion FPSO has experienced problems in the past with regards PWRI availability both in terms of the treatment system to allow for increased water injection requirements and overall capacity. Problems have also been experienced with sand accumulations and sand abrasion resulting in the PWRI systems being offline for longer periods of time. Lessons learned from the Schiehallion FPSO have been incorporated into the design of the new FPSO. For example, the new FPSO will be designed to provide protection against solids damage and the PWRI system will be designed to handle the significant quantities of produced water that are forecast. Also, in the case of any short term (2-4hr) system upset the treated produced water will be routed temporarily to an offspec cargo tank and recycled through the produced water treatment system once available. Overboard discharge will only be used as a fallback should PWRI be unavailable for longer periods of time. Open drains treatment and disposal Open drains refers to all drainage of liquids from decked or plated areas, excluding those drains hard piped from hydrocarbon containing process equipment which is handled by the closed drains system. The closed drains system is recycled Page 2.14
through process and is completely segregated from the open drains. Open drains also includes machinery space drainage. All collected open drains, from both hazardous and non-hazardous areas, are routed to the FPSO slops tanks for oil and water separation. FPSO slops tanks treatment is required to meet 15 mg/l oil in water before overboard discharge in order to meet the Merchant Shipping Regulations in particular while en-route to the new FPSO location. Three options were considered for disposal of the treated slops tanks: h Option 1 - Overboard discharge following treatment to a residual 15 mg/l oil in water concentration h Option 2 - Collection by tanker with further treatment and disposal inshore h Option 3 - Co-mingle with produced water for injection into the reservoir Option 3 - co-mingling with produced water and reinjection was not considered to be technically or strategically achievable due to the high potential for reservoir contamination and was therefore discounted. Option 2 would involve discharging treated oily water in inshore waters, which typically have greater environmental sensitivity than deeper offshore waters and was therefore not the preferred option on these grounds. The final decision was November 2010
Alternatives therefore Option 1 - overboard discharge of treated slops tanks with a residual oil in water concentration of 15 mg/l. Oil in water specification During normal operations there will be no discharge of produced water overboard; however, when the PWRI system is unavailable for extended periods, produced water will be discharged overboard. BP EPRs set a target oil in water specification of 15 mg/l. This is well below the current UK regulatory requirement of a monthly average of 30 mg/l dispersed oil in water. In addition to produced water, both open drains and machinery space drainage will be discharged overboard. The latter is required to meet 15 mg/l oil in water in order to comply with the Merchant Shipping Regulations. Two options were considered for the oil in water specification: h Option 1 - Treat all oily water discharges to a 15 mg/l residual oil in water specification h Option 2 - Treat produced water discharges to a 30 mg/l residual oil in water specification and slops discharges to a 15 mg/l specification Whilst the 30 mg/l residual oil in water specification would meet current UK statutory requirements for produced water, the decision was made to design all water treatment facilities to a 15 mg/l specification (Option 1) as it is considered technically viable and is also the best strategic and environmental option. It also meets the BP EPRs. Sewage treatment and disposal There are currently no specific requirements to treat sewage offshore, provided the installation is more than 12 miles from shore. However, while the FPSO is in transit from the shipyard to the Schiehallion and Loyal fields, sewage treatment and discharge requirements will be governed by the Merchant Shipping (Prevention of Pollution by Sewage and Garbage from Ships) Regulations 2008. These Regulations prohibit discharge of sewage within 3 miles of land unless fully treated, and require sewage to be partially treated and disinfected if discharged between 3 and 12 miles offshore. Against this regulatory background, three options were considered for sewage treatment and disposal: h Option 1 - Fitting a full sewage treatment plant. This option would allow sewage discharge within 3 miles of land and would only require a small holding tank
November 2010
h Option 2 - Fitting a partial sewage treatment plant allowing sewage to be comminuted (macerated and screened) and disinfected. This would restrict sewage discharges to beyond 3 miles from land and therefore a larger holding tank would be needed h Option 3 - Fitting no sewage treatment plant. This would increase the restrictions on discharge and require a large holding tank capable of holding sewage for considerable phases of the delivery voyage The final decision was for Option 2 - partial sewage treatment and disinfection. This allows more flexibility for sewage treatment during transit and the option to treat sewage once on station. The option is also of lower cost than a full treatment system and is aligned with the project objective of minimising impacts on the environment. Well testing and clean-up In keeping with the current requirements for the existing Schiehallion FPSO, the Quad204 design will need to include facilities which will allow testing of individual wells and allocation of production to the Schiehallion and Loyal fields on an individual well basis. In addition, there will be a programme of new drilling (see Section 3.2.2) and well intervention over the life of field and therefore facilities will be required for the testing and clean-up of those wells as they are brought on line. Well testing will not be undertaken at the drilling rig. Testing of individual production wells will be undertaken by directing fluids back to the FPSO. Two options for well testing were considered: h Option 1 - Dedicated flow line – install a dedicated flow line back to the FPSO to allow individual testing of the wells to assess their performance h Option 2 - Testing by difference – this requires no additional equipment to be installed and allows individual testing by flowing one well at a time The selected option was to test individual wells through a dedicated test line (Option 1) which forms part of the SURF infrastructure and through a dedicated test separator on the FPSO. Three options were considered in relation to the test separator: h Option 1 - Installation of a three-phase test separator h Option 2 - Installation of multiphase flowmeters on the topsides test line
Page 2.15
Alternatives h Option 3 - Installation of subsea multiphase flowmeters at each drill centre
h Option 2 - Install minimum facilities on the FPSO for sand removal
Use of a test separator vessel is a standard field proven design and is currently used on the existing Schiehallion FPSO (although only two-phase). The test separator allows for effective measurement and allocation of oil, water and gas (three-phase) production. It can also be used for well clean-up. The main disadvantage of the system is the additional space/weight requirements and the additional hydrocarbon inventory and associated safety issues topsides.
In light of existing Schiehallion operating experience and the risk of increasing sand production over field life, the decision was made to install maximum facilities and flexibility on the Quad204 FPSO for sand handling and clean-up (Option 1). This option will utilise cyclonic sand removal devices (as currently installed on the existing Schiehallion FPSO) with sand jetting for sand removal from vessels, and cyclonic devices for sand removal from produced water. All new wells will have sand detection installed on the trees and sand detection will also be retained at the top of the risers.
Topsides multiphase metering is a newer technology with less field experience, and there have been reliability issues seen. The advantage of the technology is that it offers the ability to measure the three phases in the well fluids with minimal operator intervention and with a minimal increase in topsides hydrocarbon inventory. However, the technology does not provide the facilities for well clean up and these fluids would need to be routed through the main production separators. As initial well fluids can be “dirty”, this increases the risk of production upsets potentially leading to increased flaring and produced water upsets. The meters also require regular calibration, again requiring re-routing through a separate separator. Subsea multiphase metering is similar to topsides multiphase metering and is again a relatively new technology with similar issues to topsides multiphase flow meters. The decision was therefore made to install a threephase test separator (Option 1) on the Quad204 FPSO. This option aligned with all the project goals including environment, value, strategic, field life operability, technical and deliverability. Sand removal and disposal Significant quantities of solids (primarily sand) are found in the Schiehallion and Loyal production fluids. The sand tends to be deposited in the major process vessels with finer particles being transported in produced water to downstream systems. Sand has caused a number of issues on the existing Schiehallion FPSO including erosion of equipment and pumps, impact on produced water quality, and reduction of water phase residence time in separation vessels due to sand deposition. Sand must therefore be removed from the process streams to maintain separation efficiency and protect rotating equipment, including pumps.
Option 1 meets the project goals in terms of strategic, value and field life operability and also has environmental benefits in terms of improved operational efficiency and reliability of pumps (e.g. for PWRI). There were also two options considered for sand disposal following clean-up: h Option 1 - Transport to shore for further treatment h Option 2 - Discharge to sea The decision was made to discharge cleaned sand to sea in slurry form combined with the use of BAT to minimise the oil on sand content (Option 2).
2.4.5
Gas handling and flare
Flare gas recovery Routine flaring is the normal everyday disposal of residual gas by combustion. In traditional flare systems the system is open to the flare tip and so purge gas and any other gas which enters the flare system during normal operation (such as lowpressure flash gas) is continually emitted to atmosphere via combustion at the flare tip. Routine flare volumes can be small, but continuous and therefore represent a significant source of CO2 and other combustion emissions to atmosphere. CO2 emissions from flaring are included within the EU Emissions Trading Scheme (EU ETS) and therefore every tonne of CO2 emitted from the flare has an operational cost. The BP EPRs require that elimination of continuous and routine flaring and venting shall represent the base case in project design. Elimination of routine flaring is also considered to be the BAT by DECC. Two options were considered:
Two options were considered for sand removal:
h Option 1 - No flare gas recovery
h Option 1 - Install maximum facilities and flexibility on the FPSO for sand removal
h Option 2 - Full flare gas recovery system
Page 2.16
November 2010
Alternatives The decision was made to include a full flare gas recovery (FGR) system as the base case for design (Option 2). This decision was made on value, strategic, regulatory and environmental grounds. It is also recognised that retro-fit of a FGR system is not a realistic option; therefore, inclusion of full FGR allows for any future tightening in regulation. A full FGR system will remove all routine flaring including purges and pilots. Non-routine flaring during periods of full or partial plant shutdown (e.g. for maintenance) and emergency flaring will still occur. LP compression reliability and availability An LP compression system will be used on the Quad204 FPSO to compress natural gas from the nd 2 stage separator and the HP and LP flare gas recovery vessels. Gas from these sources is often at too low a pressure to be routed directly to HP compression and therefore an LP compression system is required for operation of the FGR system. The reliability and availability of the LP compression system is therefore critical in order to avoid unnecessary flaring. Three options were identified as feasible for LP compression: h Option 1 - Single stage oil-injected screw compressor h Option 2 - Two stage oil-free screw compressor with inter-stage cooling h Option 3 - Two stage centrifugal compressor with inter-stage cooling Option 1 (single stage oil-injected screw compressor) has a history of poor reliability worldwide within BP (including the existing Schiehallion FPSO), and was therefore rejected. Option 3 was seen to have the greatest reliability however was rejected due to high cost, large footprint area and lack of flexibility to changes in the process conditions. The decision was therefore made to use a two stage oil-free compressor with inter-stage cooling (Option 2), which will give good reliability of the LP compression system. Availability of the LP compression is also critical to reduction of flaring volumes as FGR will be offline when the LP compressor is not available (e.g. due to maintenance). Availability and sparing of the LP compressor was therefore also assessed, and a 1 x 100% sparing philosophy selected. It was found that this will give a mean availability of 98.5%. Increasing sparing (e.g. 2 x 50% machines or 2 x 100% machines) did not increase availability significantly in order to justify the increased cost and space requirements. November 2010
Cargo tank blanketing and export VOC recovery facilities There are two potentially major sources of vented hydrocarbons from the Quad204 FPSO: h Tank venting from storage of crude h Cargo transfer operations to the shuttle tanker This gas typically contains a significant quantity of volatile organic compounds (VOCs) including methane and is a potentially significant environmental impact. This issue has been recognised since the early design of the existing Schiehallion FPSO and led to the installation of an inert gas return system from the tanker to the FPSO, which made a significant reduction in VOC emissions. This system was the first VOC return system installed on the UKCS. However, following a collision incident on the Schiehallion FPSO the VOC recovery system is no longer in use and has not been replaced. As a result there are significant emissions of VOCs from FPSO storage tank venting from existing operations. Environmental regulation and associated emission reduction technology have progressed since the design and installation of the existing Schiehallion FPSO, and a number of options now exist for the Quad204 design for reduction of VOCs from cargo tank venting and cargo transfer operations. In order to prevent the build-up of a flammable mixture in the cargo oil tanks (COTs) a positive pressure in the storage tanks must be maintained to avoid any air ingress and to achieve this the COTs must therefore be blanketed with some form of nonoxygenated vapour. Three options were considered for cargo tank blanketing: h Option 1 – Blanket with hydrocarbon (HC) gas and recycle the gas during tank filling back to the process h Option 2 – Blanket with inert gas (IG), compress the gas during tank filling and discharge to a safe location via the LP flare system h Option 3 – As for Option 2, but discharge the gas during filling direct to vents located in a safe location some distance up the flare tower Table 2.7 summarises the output of the decisionmaking process for cargo tank blanketing and venting. Although it represented the highest CAPEX and system complexity, overall the adoption of Option 1 was judged the best approach for Quad204. Option 1 meets the requirements of the Quad204 EPRs and will lead to a significant reduction of VOC emissions.
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Table 2.7: Decision-making process for cargo tank blanketing
This is considered to be the BAT and will also reduce future risks of non-compliance and emissions trading costs if environmental regulation on venting of methane is increased. Lessons learned from Schiehallion and FPSOs utilising HC gas blanketing will be incorporated into the design of the new FPSO. A number of options were also considered for VOC recovery during oil offloading to shuttle tankers for export: h Option 1 – Install VOC recovery facilities on the FPSO h Option 2 – Provide VOC recovery facilities on the shuttle tanker h Option 3 – No VOC recovery provisions Prior to the collision incident, the existing Schiehallion FPSO had VOC recovery facilities onboard, and VOCs were returned from the shuttle tanker to the cargo oil tanks. However, this is not practicable with the use of HC blanketing in the cargo tanks as per the Quad204 design, and Page 2.18
dedicated recovery tanks would be required. Returned gases, which would contain a mixture of hydrocarbon and inert gas, would be stripped before the gas is vented to atmosphere at a safe location. Dedicated tanks and gas stripping equipment would entail significant CAPEX as well as major weight/space demands and additional operational/maintenance complexity. An additional complexity is the requirement for the shuttle tanker to have the required hose connections. Option 2 uses the same equipment as Option 1, but in this case the equipment is located on the shuttle tanker. Such systems are now standard practice for shuttle tankers operating in the Norwegian sector of the North Sea, with Norwegian legislation requiring a 95% reduction in the VOC emissions resulting from offshore loading by the end of 2005. The Norwegian Climate and Pollution Agency (Klif) reported a 9.8% 1 reduction in non-methane VOCs (nmVOC) between
1
nmVOC – non methane VOC emissions from storage vessels and shuttle tankers.
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Alternatives
Table 2.8: Decision-making process for power generation
2008 and 2009 with a total reduction of more than 80% since 2001 (Klif, 2009). A number of systems have been developed commercially and installed on both shuttle tankers and very large crude carriers (VLCCs). These systems employ a range of technologies and vary in the degree to which they can remove VOCs and methane. Such systems onboard shuttle tankers also have the added benefit of minimising VOC emissions from the shuttle tanker cargo tanks during transit. A review of shuttle tanker operators has indicated that in the timeframe of the Quad204 Project it is expected that the use of VOC recovery on board suitable new build shuttle tankers will be common practice. Option 3 was rejected as the volumes of VOC emissions were not considered acceptable and this option was not aligned with the project goals. The final decision was Option 2 - recovery of VOCs during oil offloading will be undertaken on the shuttle tanker.
November 2010
2.4.6
Power generation
Three options were considered for power generation: h Option 1 - Power from shore h Option 2 - Conventional offshore gas turbines h Option 3 - Offshore Combined Cycle Gas Turbines (CCGT) Table 2.8 summarises the output of the decisionmaking process for power generation. A number of interrelated studies were undertaken to support the decision-making process including BAT assessments, detailed technical studies for each of the options, and review of experience elsewhere. A detailed study on the potential for providing power from shore was conducted, and although seen to have some environmental benefits, including reduced emissions, it was concluded that the technical risks and deliverability risks far outweighed Page 2.19
Alternatives these benefits. Similar evaluation studies of CCGT were also undertaken, and although CCGT offers very attractive environmental savings, the configuration is not able to deliver the power required by the project. In addition reliability issues and limited operational experience introduced an unacceptable level of risk. The decision was therefore made to use conventional offshore gas turbines (Option 2).
to the lack of spare generating capacity. Current operating efficiency is approximately 60%. The new FPSO will be designed to provide significant improvement in operating efficiency and will ensure that the power generation installed on the new FPSO is significantly robust enough to cope with any upset to one of the turbines and its associated generator. A secure power supply is also critical for ensuring water injection system availability.
Turbine fuel supply
Two options were considered for turbine configuration:
The decision was made for the turbines to be all dual fuel (fuel gas or diesel). This option provided the project the opportunity to significantly improve on operational efficiency, as well as greater flexibility, standardised equipment and redundancy for power start-up. Current Quad204 production forecasts indicate that the field will become fuel gas deficient in the future. Two options were considered to address future fuel gas deficiency: h Option 1 - Import gas from the WOSPS h Option 2 - Increase use of diesel to supplement fuel gas deficiency The decision was made to import gas from WOSPS (Option 1) in the event of future fuel gas deficiency. This option is the better environmental option with fuel gas combustion generating significantly lower emissions than diesel combustion. It was also the preferred option in terms of value, as diesel is of a much higher cost; and field life operability with risks associated with supply boat delivery of diesel and weather downtime. It should be stressed that this decision excluded the review of reservoir depletion optimisation and development of additional gas rich resources rd including 3 party developments. These business opportunities may remove the risk of fuel gas deficiency, however it was felt prudent to consider the options as none of these opportunities are guaranteed. Turbine configuration Power generation on the FPSO is essential for the provision of a secure, reliable and flexible power supply. The existing Schiehallion FPSO has two turbine generators. However, due to reliability issues with these generators the Schiehallion operations have been significantly impacted resulting in process upsets leading to reduced production or loss of production. Should one of these turbines shut down, the other turbine cannot supply the total load requirement resulting in an adverse impact on production. Currently this impact is made worse due Page 2.20
h Option 1 - n configuration to supply the defined 2 load h Option 2 - n+1 configuration to supply the defined load 3 Option 1 reduces the number of installed turbines required to meet power requirements and the loss of one turbine could adversely impact on production and operating efficiency. However, an n+1 philosophy (Option 2) is a common design concept which allows for the staggering of routine maintenance and overhauls so that the required number of turbines is available for the majority of the time, hence minimising the effect of downtime and therefore increasing operating efficiency. The final decision was Option 2 - an n+1 turbine configuration. Compressor driver types The LP compression train and also the vapour recovery unit (VRU) and air compression facilities can only be run through the use of an electric motor. The HP gas compression trains, however, can either be run by electric drive or by direct drive from the gas turbine. Both of these options were therefore considered for the HP compressor driver type: h Option 1 - Direct drive h Option 2 - Electric drive Electric drive has significantly lower emissions and higher energy efficiency than is seen by direct drive and is the environmentally preferred option. In addition electric drive is considered to be the inherently safer design option. Although electric drive involves higher CAPEX, it does have overall lower OPEX with reduced fuel consumption by virtue of increased efficiency. Electric drive also meets one of the key project goals of improving field operability by having greater availability and removing reliance
2
Where n is the number of turbines required for a defined load 3
Where n+1 provides backup through an additional gas turbine
November 2010
Alternatives on process heat supply. The selected option was therefore electric drive for the HP gas compression trains (Option 2). Turbine emissions control There are various techniques for reducing NOx and SOx emissions and these can be described as wet or dry. Wet techniques involve the injection of water or steam whereas dry techniques involve changes in combustion configuration. The installation of wet technologies, whether water or steam injection, requires the installation of large water purification systems; with space/weight limitations on the FPSO and the increased complexity of wet technology operation. Wet technologies were not considered a viable option. The project therefore considered two main options when reviewing turbine emission control: h Option 1 - Install dry low NOx emissions (DLE) dual fuel turbines h Option 2 - Install DLE ready dual fuel turbines BP’s experience in the use of DLE dual fuel turbines has found that it is generally unreliable resulting in operational problems including mechanical failures. The mechanical and emissions performance of DLE gas turbines is dependent on load. High loads have resulted in satisfactory performance, but operation at lower loads has proved problematic. Operational problems have included failures of combustors and exhaust collectors, plant upsets and requirements for intervention on the diesel system. BP’s experience to date has been taken into consideration in the design of the new FPSO power generation system. The decision was therefore made to install DLE ready dual fuel turbines (Option 2). At each major overhaul of the turbines, BP will review legislation and technology readiness in considering implementation of DLE technologies.
2.5 Decisions remaining to be made and future options The decision-making process will continue to be implemented by the Quad204 project team during detailed design and environmental assessment will continue to be an element of the decision-making process. There are a number of decisions remaining to be made and future options that are outlined below:
would reduce the overall well requirements in order to access un-recovered reserves, with an associated reduction in surface footprint and volumes of cuttings discharged overboard and/or disposed of to shore. Conventional well design, which has the greatest surface footprint and greatest drill cuttings volumes, has been assumed for the purposes of this ES. h BP is continuing to monitor offshore treatment technologies for oil based mud (OBM) contaminated cuttings, and this remains an opportunity for the future, although the practicality of this will largely depend on rig selection and available deck space. h Although it is assumed for the purposes of this ES that a conventionally moored 4th generation semi-submersible drilling rig will be used for the Quad204 Project, the final rig selection is still to th th be made and may result in the use of a 4 , 5 or th 6 generation rig. h The installation of subsea pumping facilities has been considered in the past as an option to alleviate constraints on flowline networks experienced in the Schiehallion field. Subsea pumping facilities would help reduce backpressure on the wells, increase well drawdown, and lead to an increase in oil production rates and reserves. The decision was taken not to install subsea pumps as part of the Quad204 Project. However, provision for 9.8 MW of power has been made in the design of the power generation system and a dynamic/static power umbilical may be provided to the seabed so that any future developments such as subsea processing and potential de-bottlenecking can be accommodated. h Polymer flood enhanced oil recovery (EOR) facilities will be included on the new FPSO, however, the decision on whether to implement EOR is still to be made. If EOR is implemented an emulsion form of the polymer will be used. h It is currently anticipated that the gas disposal well at An Teallach will be suspended, however, the final decision is still to be made. h The oil process system will be designed to allow for the possible future installation of a VIEC. The decision on whether to install a VIEC for Quad204 is still to be made and will be based on operating experience from Schiehallion.
h Multilateral well technology has been utilised on one Schiehallion well to date and is a future well design option, to be considered on an individual well basis, which will enable wells to target multiple sands. The use of multilateral wells November 2010
Page 2.21
Alternatives
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Page 2.22
November 2010
The Development
3
The Development
This chapter provides an overview of the proposed Quad204 Project at the end of the Front End Engineering Design (FEED) stage of the project design, which forms the basis of the detailed EIA reported in Chapters 6 to 11 of this ES.
3.1
Fields and reservoirs
3.1.1
Overview
The existing Schiehallion/Loyal development accesses reserves from the Schiehallion and Loyal fields via five drill centres located at Central, West, Northwest, North and Loyal. The Quad204 Project aims to develop additional reserves from the
Schiehallion and Loyal fields. The reservoirs in these fields lie within the Lower Palaeocene stratigraphic sequences and comprise stacked deep water turbidite sandstones, with a combination of both channel and sheet-like complexes. There is extensive faulting which results in significant compartmentalisation of the hydrocarbon accumulations. The Base Case of the Quad204 Project is to exploit the hydrocarbon resources from the Lower Palaeocene sands of both the Schiehallion field (T25-T35 reservoirs) and Loyal field (T35 and T31 reservoirs) (Figure 3.1).
3.1.2
Fluid characteristics
Fluids from the Schiehallion and Loyal fields are all high-density oils with a relatively low proportion of volatile components. They are broadly similar, with an American Petroleum Institute (API) gravity of 26
Figure 3.1: Schiehallion and Loyal reservoir overview
November 2010
Page 3.1
The Development and 25 respectively, which is classed as a medium crude oil. Oil characteristics for Schiehallion and Loyal are summarised in Table 3.1.
Oil characteristic
Field Schiehallion
Loyal
Density (g/cc)
0.898
0.904
Specific Gravity o ( API)
26
25
Viscosity (cP)
3.27
1.86
Wax content (%)
9
5.2
Asphaltenes (%)
0.3
3.6
Initial GOR (scf/stb)
380
512
3.2
Wells and drilling
3.2.1
Well strategy
The overall well strategy is to use a combination of moderate to high severity multi-zonal wells at existing drill centres. The Quad204 well designs will be a continuation of those utilised for the existing development wells. New technology such as multilateral wells is also a long-term option which may reduce the total number of new wells (see Section 2.5). For all new wells the project will use a conventionally moored 4th generation (or higher) semi–submersible drilling rig. The drilling programme will be scheduled to maximise the production availability through the FPSO and is expected to start in 2014. The drilling strategy and schedule will be confirmed during detailed engineering.
Table 3.1: Schiehallion and Loyal oil characteristics
3.1.3
Seismic survey
Repeat seismic surveys have been conducted, following the 1996 4D baseline, in 1999, 2000, 2002, 2004, 2006, 2008 and 2010 in order to investigate the Schiehallion and Loyal reservoirs. An ongoing programme of seismic data acquisition is expected, whilst active infill drilling continues, with the next planned survey in 2012 and every two years thereafter. A 4D seismic survey involves a vessel towing a number of cables carrying hydrophones and air gun sources through the water column. The hydrophones record pressure waves generated by the air gun sources. No cables or equipment are placed on the seabed for the survey. The array’s position within the water column is controlled by a series of flotation devices, which are remotely controlled by the survey vessel to ensure that the array remains at a constant depth below the sea surface. The survey vessel towing the air gun array will in general sail along around 100 or so prime sail lines, each of which will be on average 20 km in length and nominally 400 m apart. Each sail line takes approximately three hours to complete. In order to prevent the array cables becoming entangled, the vessel will have to make a wide turn before commencing the next survey line. Each line turn is expected to take up to three hours to complete. A survey vessel is expected to be in the Quad204 Project area for approximately 56 days every two years until 2020.
Page 3.2
Figure 3.2: Typical 4th generation semi-submersible drilling rig
3.2.2
Well programme
The current well stock in the Schiehallion and Loyal fields consists of 54 wells: 22 producers (2 of which originate from a single multi-lateral well) and 23 water injectors at Schiehallion, 4 producers and 4 water injectors at Loyal, and a gas disposal well. The gas disposal well was employed in early production field life before operation of the West of Shetland Pipeline System (WOSPS) in 2002 and is no longer in use. It is currently anticipated that this well will be suspended, however, the final decision is still to be made (see Section 2.5). In order to fully exploit the remaining recoverable reserves, it is currently estimated that up to 49 new subsea production and water injection wells may be required at Schiehallion and Loyal, drilled in a number of phases, dependent upon prevailing November 2010
The Development Drill centre
West
Central
Existing wells
Quad204 Base Case Phase 1 potential infill wells
Potential total wells (Existing wells + Phase 1 infill wells)
Approximate timescale for infill drilling
2015-2021
6 x production
6 x production
12 x production
9 x water injection
3 x water injection
12 x water injection
14 x production
3 x production
17 x production
9 x water injection
1 x water injection
10 x water injection
North
3 x water injection
1 x water injection
4 x water injection
2015-2021
Northwest
1 x production (ML)*
5 x production
6 x production
2015-2021
2 x water injection
1 x water injection
3 x water injection
Loyal
4 x production
3 x production
7 x production
4 x water injection
2 x water injection
6 x water injection
Gas Disposal
1 x gas injection
-
1 x gas injection
Totals
26 x production (2 wells originating from a single multi-lateral well)
17 x production
42 x production (2 wells originating from a single multi-lateral well)
8 x water injection
27 x water injection
35 x water injection
1 x gas injection
1 x gas injection
2015-2021
2014-2017
-
*ML = Multi-lateral well Table 3.2: Existing wells and Quad204 Phase 1 potential infill wells
economic conditions. All planned wells will be infill drilling (i.e. the addition of new wells to an existing field within the original footprint) at existing drill centres. Phase 1, the Base Case for the Quad204 Project, consists of an additional 25 infill wells (20 at Schiehallion and 5 at Loyal) comprising 17 producers and 8 water injectors located at the five drill centres: West, Central, North, Northwest, and Loyal. It is anticipated that these wells will be drilled in a continuous drilling programme between 2014 and 2021 using one or two mobile drilling rigs. Six of the producers will be pre-drilled to aid in production ramp up on the new FPSO. Long term upside development plans (Phases 2 and 3 drilling campaigns) include the potential for an additional 24 infill wells (23 at Schiehallion and 1 at Loyal). These wells will also be sanctioned on a well by well basis dependent upon further work to mature the options and prevailing economic conditions. The drilling programme includes a number of planned workovers, with additional workovers planned from 2026 to 2030 (see Section 3.2.7). There may also be a requirement for up to 5 appraisal sidetracks/pilot holes. There are currently no planned sidetracks of the existing well infrastructure. However, sidetracks could be performed when production is lost from a well due to injection water breakthrough or where there is a significant failure at the sandface completion in the reservoir. The sandface November 2010
completion is the most likely part of the completion to fail with time, either due to mechanical failure and/or sand fill. Sidetracks involve plugging and abandoning the current reservoir section, removing the upper completion and sidetracking the well to a new reservoir target location, prior to re-completing the well. The well programme assumes no use of multi-lateral well technology (see Section 2.5). However, this will be reviewed during final detailed well planning where all available technologies will be considered. Table 3.2 summarises the existing wells and potential infill wells at the individual drill centres together with the well type. The location and timing of potential infill wells are subject to change. There are no new drill centres planned as part of the Quad204 Project. However, there is potential for the future creation of a new drill centre to develop the Alligin field and/or other future fields by tie-back to the Schiehallion and Loyal infrastructure. Any development associated with the Alligin and/or other future fields will be subject to a separate EIA process and presented as an addendum to this Environmental Statement (ES).
3.2.3
Well design and drilling mud selection
Wells will be directionally drilled to intercept the Page 3.3
The Development target reservoir rock in the optimum orientation taking into account the limitations imposed by the existing drill centre locations. A typical Quad204 well design is shown in Figure 3.3. The 36” and 26" hole sections are generally drilled vertically below the seabed. Subsequent hole sections (17½", 12¼" and 8½") are drilled by increasing the inclination to access single zone reservoir targets at +/- 45 degrees and multiple zone reservoir targets at +/- 90 degrees (horizontal wells).
h WBM for the middle hole (17½") section
Drilling muds have a number of functions including maintenance of downhole pressure, removal of drill cuttings generated by the drill bit to the surface, lubricating and cooling the drill bit and string, and deposition of an impermeable cake on the wall of the “well bore” sealing and stabilising the formations being drilled. Based on experience gained over the drilling of previous Schiehallion wells, drilling fluid requirements for a typical Quad204 well design fall into four broad categories:
h Where wells are completed using gravel pack technology rather than standard sand screens (Section 3.2.6), WBM will be used in the 8½" section due to chemical compatibility issues
h Simple water based mud (WBM) for the surface and upper hole (36” and 26") sections
WBM cuttings from the tophole sections will be discharged to the seabed. Drill cuttings
h Typically, oil based mud (OBM) for the lower hole (12¼" and 8½") sections suitable for extended reach drilling into the reservoir formation. Low toxicity mineral oil is used as the base fluid for these mud systems. OBMs reduce torque and drag as well as maintaining well bore quality and optimum conditions for high quality fracture identification, data acquisition and minimum formation damage
3.2.4
Drill cuttings handling
Figure 3.3: Typical Quad204 well design (4 string)
Page 3.4
November 2010
The Development contaminated with WBM from the middle hole section will be discharged from the mobile drilling rig into the sea following cuttings cleaning and mud recovery operations. OBM contaminated drill cuttings are currently shipped to shore for treatment and disposal and this will be the base case for the Quad204 Project well programme. Offshore treatment of OBM contaminated cuttings is being considered as an option (See Section 2.5).
3.2.5
Cementing
Steel casings will be installed in the well during the drilling operation to provide structural strength and to isolate unstable formations and different formation fluids. Each casing will be cemented into place to form a seal between the casing and the formation. Most cement will remain in the well bore, however, some cement will be discharged to the seabed during the setting of the top section.
3.2.6
Completions and well clean up
After drilling the 8½" section to total depth, the well will be circulated clean of cuttings and mud before running the sandface completion. There are various types of sandface completion equipment and all have been installed in Schiehallion/Loyal wells to date including stand alone screens (SAS), expandable sand screens (ESS) and open hole gravel packs (OHGP): h SAS provide basic sand control that prevents production of sand up the well h ESS can provide improved sand management as the screen is expanded reducing the annulus between the screen and the formation h OHGP provide improved sand management over conventional sand screens and will be used on wells where significant sand control problems are anticipated The decision on which sandface completion equipment will be used for the Quad204 wells will depend on the final reservoir section well design requirements. It is anticipated that ‘enhanced sand control sandface completions’ will be installed utilising ESS or OHGP. However, other well design factors could result in SAS being installed. For example, ESS and OHGP are limited to a reservoir section of +/-1500 m and the requirement for downhole flow control (DHFC) could result in a SAS completion. Once the sand completion has been run and set, clean up chemicals will be circulated and the remaining drilling mud (and well clean up fluids) recovered to surface and replaced by completion brine. Where these are contaminated with OBM or November 2010
reservoir hydrocarbons, these will be captured on the drilling rig and shipped to shore for disposal. Finally, the upper completion is run down the well. For production wells, all fluid remaining in the well will be directed to the FPSO for processing. For water injection wells, no fluid will be processed through the FPSO. Water injection wells are likely to be drilled with WBM, in which case any remaining drilling fluid in the well will be displaced to a low solids fluid prior to the start of water injection. Any clean (<30 mg/l dispersed oil in water) drilling fluid will be discharged to sea with any contaminated fluids captured on the surface and returned onshore for processing/clean up. If OBM is used to drill the water injection well, fluids will be displaced and shipped to shore.
3.2.7
Workovers and interventions
In addition to new well construction, workovers and interventions will be carried out to maintain and repair the existing well stock, to acquire downhole data for reservoir management, and/or to enhance the effectiveness of the well by shutting off nonproductive zones. The frequency of workovers and interventions is difficult to predict and can only be forecast based on historical data of types of well failure. The type of well failure is what determines whether the repair involves a sidetrack, workover or well intervention. Workovers and interventions will involve the use of drilling fluids and chemicals and the return to surface of wellbore debris. Depending on the application, fluids and chemicals may be returned to surface for treatment and discharge; shipped to shore for appropriate disposal or re-use; remain in the wellbore or reservoir; or be produced to the FPSO. Workovers Workovers involve the removal and replacement of the upper completion, and are carried out where the condition of the existing completion tubing or completion equipment (e.g. down hole safety valve) has deteriorated and is no longer fit for purpose and where repair cannot be carried out by intervention (see below). Track records to date indicate that the upper completion design is fit for purpose and that workovers for repair will be infrequent. Interventions Interventions involve the downhole re-entry inside the existing completion, and will be carried out to maintain and enhance the value of the existing well stock. Wireline or coil tubing interventions from moored or dynamically positioned drilling rigs or dynamically positioned light well intervention vessels Page 3.5
The Development (LWI) will be carried out for a wide variety of reasons. These may include removal of sand fill and repair of sandface completion; acquisition of downhole data, e.g. pressure and flow rate; shut off of zones in the wellbore by mechanical or chemical means; and stimulation of zones to enhance productivity or injectivity. Well interventions in subsea wells are a relatively new area of activity. While the equipment, vessels and techniques to execute a safe entry into the wellbore are well established and proven in the West of Shetland environment, the downhole tools and techniques to successfully repair or modify the wellbore are less established. The frequency of interventions is therefore uncertain and will depend on both the frequency of the problem and the track record of successful interventions. Allowance in the drilling schedule Sand fill in the lower completion, is the most likely well problem in the Schiehallion/Loyal wells and will not be dealt with by a workover. Either a well intervention to remove sand and repair the sandface completion will be attempted or the well will be sidetracked (Section 3.2.2). Tree and tubing removal will also be carried out as the first steps in conventional well sidetracks. Based on historical information, a workover every year (for an average duration of 60 days) has been built into the drilling schedule. This will be within the new well drilling schedule from 2014 to 2021 (Phase 1) and then batched in groups of 5 and 4 in 2026 and 2030 respectively. The exact timing of these workovers is subject to change, but the total number is believed to be representative. For the purposes of this EIA, an average duration of 60 days has been allowed for each well intervention/sidetrack. In addition, a total intervention time of 30 days per year has been included utilising a LWI vessel.
Page 3.6
3.3
Production overview
3.3.1
Introduction
The following sections outline the forecasted production figures from the Schiehallion and Loyal fields. The figures show production from existing well stock from 2010 – 2014 and peak production from existing well stock and new Quad204 Phase 1 infill wells (referred to as the Base Case) for the period 2015 – 2035. The dip in 2014, represented in all figures, is due to the existing FPSO production ending in 1Q 2014 as the project prepares to disconnect the FPSO. The new FPSO is due to start up in 4Q 2015. Full production profiles (peak and average) and assumptions made are provided in Appendix C.
3.3.2
Oil production profile
Total oil production from the Schiehallion and Loyal wells is expected to peak at ca. 20,000 tonnes/day in 2016 following start-up of the new FPSO before steadily declining over field life, through natural depletion (Figure 3.4 and Table 3.3).
3.3.3
Gas production profile
Total gas production from the Schiehallion and Loyal wells is expected to peak significantly in 2016 at ca. 3.5 million sm3/day before steadily declining over field life, through natural depletion (Figure 3.5 and Table 3.4).
3.3.4
Produced water profile
Produced water from the Schiehallion and Loyal wells is expected to increase steadily following startup in 2015 to ca. 45,000 tonnes/day and remain at this level through to 2035 (Figure 3.6 and Table 3.5).
November 2010
The Development Note: There will be no production between 2Q 2014 and 3Q 2015. Existing FPSO production will cease in 1Q 2014 with new FPSO production expected from 4Q 2015.
Figure 3.4: Peak oil production forecast for Schiehallion and Loyal
Figure 3.5: Peak gas production forecast for Schiehallion and Loyal
Figure 3.6: Peak produced water forecast for Schiehallion and Loyal
November 2010
Page 3.7
The Development
Year
Schiehallion existing wells
Loyal existing wells
Quad204 Schiehallion 20 infill wells (base case)
Quad204 Loyal 5 infill wells (base case)
Total peak oil production rate
tonnes/day
tonnes/day
tonnes/day
tonnes/day
tonnes/day
2010
4,773
645
5,418
2011
4,897
662
5,560
2012
6,702
854
7,556
2013
4,971
579
5,550
2014
759
88
848
2015
1,515
119
155
77
1,866
2016
16,237
1,640
732
1,211
19,819
2017
13,116
1,376
921
1,237
16,650
2018
10,197
1,133
2,231
1,426
14,987
2019
8,752
964
3,127
1,481
14,325
2020
7,820
866
2,466
1,308
12,460
2021
6,954
786
1,891
941
10,571
2022
6,380
721
1,365
745
9,211
2023
5,583
671
1,334
595
8,183
2024
5,127
636
985
456
7,203
2025
4,772
610
703
354
6,439
2026
4,362
567
680
317
5,926
2027
4,162
499
703
301
5,665
2028
3,800
475
657
279
5,210
2029
3,528
424
706
339
4,996
2030
3,348
406
698
322
4,773
2031
3,479
389
561
283
4,711
2032
4,020
385
471
222
5,098
2033
3,297
367
477
187
4,328
2034
2,732
356
688
152
3,927
2035
2,480
345
805
138
3,767
Note: There will be no production between 2Q 2014 and 3Q 2015. Existing FPSO production will cease in 1Q 2014 with new FPSO production expected from 4Q 2015. Table 3.3: Peak oil production forecast for Schiehallion and Loyal
Page 3.8
November 2010
The Development Year
Schiehallion existing wells 3
Loyal existing wells
3
Quad204 Schiehallion 20 infill wells (base case) 3
sm /day
Quad204 Loyal 5 infill wells (base case) 3
sm /day
Total peak gas production rate 3
sm /day
sm /day
sm /day
2010
456,159
63,156
519,315
2011
444,439
65,313
509,752
2012
582,703
86,953
669,656
2013
402,101
58,487
460,589
2014
57,737
8,932
66,669
2015
104,308
11,946
60,389
128,498
305,141
2016
1,579,201
178,877
1,635,778
154,451
3,548,308
2017
1,130,377
167,153
1,423,913
95,436
2,816,879
2018
974,463
145,955
1,072,540
112,419
2,305,377
2019
817,264
124,080
1,075,093
128,395
2,144,832
2020
667,497
106,142
1,070,455
117,225
1,961,320
2021
586,845
94,933
952,251
87,584
1,721,612
2022
537,183
81,268
649,144
71,275
1,338,870
2023
460,747
75,227
312,973
58,678
907,626
2024
403,334
68,769
181,084
46,025
699,212
2025
363,360
64,161
94,313
36,828
558,661
2026
331,245
59,756
173,340
33,438
597,779
2027
299,282
51,949
75,456
31,646
458,333
2028
270,656
49,904
115,224
29,709
465,493
2029
249,274
44,287
119,129
38,038
450,727
2030
234,367
42,055
84,549
35,933
396,905
2031
264,623
40,279
57,734
32,380
395,017
2032
341,492
39,477
42,029
25,486
448,485
2033
308,239
37,774
83,318
22,098
451,429
2034
264,277
36,596
87,710
18,004
406,587
2035
205,239
35,484
72,608
16,433
329,764
Note: There will be no production between 2Q 2014 and 3Q 2015. Existing FPSO production will cease in 1Q 2014 with new FPSO production expected from 4Q 2015. Table 3.4: Peak gas production forecast for Schiehallion and Loyal
November 2010
Page 3.9
The Development Year
Schiehallion wells (existing and Quad204 infills)
Loyal wells (existing and Quad204 infills)
Total peak produced water rate
tonnes/day
tonnes/day
tonnes/day
2010
4,554
1,376
5,930
2011
4,705
1,509
6,213
2012
7,101
2,270
9,371
2013
5,678
1,836
7,514
2014
952
299
1,251
2015
834
379
1,213
2016
19,385
5,274
24,659
2017
25,773
6,423
32,196
2018
27,334
6,485
33,819
2019
29,228
6,614
35,842
2020
31,015
6,921
37,936
2021
32,599
7,428
40,027
2022
33,945
7,724
41,669
2023
34,766
7,951
42,717
2024
35,768
8,148
43,916
2025
36,475
8,294
44,769
2026
36,974
8,384
45,359
2027
37,182
8,479
45,662
2028
37,683
8,532
46,215
2029
38,077
7,639
45,716
2030
38,160
7,404
45,564
2031
38,044
7,423
45,468
2032
37,598
7,423
45,021
2033
37,741
7,160
44,901
2034
38,696
7,003
45,698
2035
38,062
7,033
45,095
Note: There will be no production between 2Q 2014 and 3Q 2015. Existing FPSO production will cease in 1Q 2014 with new FPSO production expected from 4Q 2015. Table 3.5: Peak produced water forecast for Schiehallion and Loyal
Page 3.10
November 2010
The Development
3.4
Subsea infrastructure
3.4.1
Overview
The Quad204 Project will involve the continued use of the existing Schiehallion and Loyal subsea infrastructure including the removal, re-installation or replacement of some existing subsea facilities and the addition of new subsea infrastructure. All of the existing production and water injection wells will continue to be used along with the existing production manifolds tied back to the new FPSO via a system of subsea flowlines and flexible risers. The five existing drill centres will be expanded by providing additional well slots. Existing and/or new subsea infrastructure will be used to connect the wells to the subsea facilities. It is envisaged that replacements/modifications to manifolds will take place as appropriate to deal with increased production levels. To accommodate the additional wells two new manifolds will be required; one production manifold and one water injection manifold.
Most of the existing subsea umbilicals will also continue to be used although two new static umbilicals will be installed. Five new production flowlines will be installed and tied back to the new FPSO. Production and water injection trees will be installed along with their associated jumpers for the new wells listed in Table 3.2. It is expected that some reconfiguration of drill centre control jumpers will take place (Section 3.4.4). Table 3.6 provides a summary of existing flowlines, umbilicals, risers and manifolds, and the additions/changes being made as a result of the Quad204 Project. Figure 3.7 shows the proposed subsea infrastructure for the Quad204 Project.
Existing Infrastructure
New Infrastructure
10 x production flowlines
5 x production flowlines
Changes to Existing Infrastructure Resulting from the Quad204 Project
7 x water injection flowlines 3 x gas lift flowlines 2 x gas lift/export flowlines 1 x gas disposal flowline (currently unused) 3 x dynamic umbilicals
The existing gas disposal well may be suspended 1 x dynamic umbilical Note: 1 x dynamic/static power umbilical may be provided to accommodate any future subsea pumping facilities (see Section 2.5)
6 x static umbilicals (1 currently unused)
2 x static umbilicals
3 x existing dynamic umbilicals will be removed. Of these: One will be replaced by the new dynamic umbilical One will be repaired, re-tested and reinstalled 2 x existing static umbilicals will no longer be used and left in situ. These will be replaced with the two new static umbilicals
1 x control umbilical (currently unused) 15 x risers
6 x risers (5 production risers and 1 gas riser)
10 x production manifolds
1 x production manifold
7 x water injection manifolds
1 x water injection manifold
Table 3.6: Existing and new flowlines, umbilicals, risers and manifolds
November 2010
Page 3.11
The Development
Figure 3.7: Overview of proposed new subsea infrastructure at the Schiehallion and Loyal fields
The following sections describe the subsea Page 3.12
infrastructure that will be installed within the development area in order to accommodate the November 2010
The Development Quad204 well programme over life of field.
3.4.2
Wellheads and trees
All new wells will have drill through horizontal trees (DTHTs) with a flowbase, as currently installed on Schiehallion and Loyal. The tree will have an arrangement of hydraulically operated valves, with manual back-up valves, to provide pressure integrity barriers from the reservoir for primary well control and a mechanism for well entry during well interventions. All wells will have a downhole safety valve (DHSV) installed which is an isolation device that is hydraulically operated. In an emergency shut down situation the hydraulic valves on the tree and the downhole safety valve will be failsafe closed. In addition to the production flowline from the production wells, there will also be a flowline providing gas lift via the tubing/production casing annulus to optimise well production. The gas for gas lift will be directed to the wells from the new FPSO via gas injection flowlines. Water injection will be used to maintain reservoir pressure and sweep oil towards the production wells. The water for injection will be directed to the wells from the new FPSO via water injection flowlines. The production and water injection trees will be remotely controlled from the new FPSO via control umbilicals (Section 3.4.6) through a number of hydraulically activated valves and chokes. The valves will be controlled using a subsea control module (SCM), which is mounted on the tree. Features of the completion include a subsea safety valve, and pressure sensors in the production string, which will provide data on production and performance and well integrity. Gas for gas lift will be distributed to the production trees from the production manifold by jumpers (Section 3.4.4). The wellhead and tree system will have an integral protection structure which will minimise the impacts of damage from fishing gear snagging by deflecting any fishing gear away from the tree system. Also, the tree system will have an integrated grated or plated roof structure which will protect it from damage by dropped objects.
3.4.3
Manifolds
The manifold design for both the water injection and the production manifold is based on the designs used for other manifolds in the Schiehallion field. The manifolds are gravity-based structures (i.e. no piling required). Indicative dimensions of the water injection manifold are 4.5 x 4 x 7 m with a weight (in air) of 40 tonnes. Indicative dimensions of the production manifold are 4.5 x 5 x 7 m with a weight (in air) of 70 tonnes. The manifolds house a complex arrangement of valves, which permit co-mingling of November 2010
flow from different wells into a choice of designated flowlines. The arrangement of valves also enables round-trip pipeline pigging in the case where more than one flowline is installed.
3.4.4
Flowlines and jumpers
Production fluids will access the new FPSO using the existing subsea architecture and 5 new production flowlines. A gas import line will also be incorporated into the existing gas lift flowline at the Loyal drill centre. Any new flowlines will be of similar design and construction as existing facilities and will have the same specifications as those already currently used: h 8” or 10" production flowlines h 10" or 12" water injection flowlines h 6” or 8" gas lift flowlines h 6" x 6" x 2" flexible jumper bundles Flowlines will be rigid and laid on the seabed. Where possible, new flowlines will be laid within existing route corridors. New and existing flowline routes are outlined in Figure 3.7. Flowline routes will follow the most direct route between locations as far as possible, unless constrained by the configuration of the new FPSO risers and future possible tie-in points, the layout of existing flowlines and FPSO/drilling rig anchor patterns. In the event that flowline crossings are required, concrete mattresses may be used for protection. Flexible flowline jumpers will be used to connect between the wellheads and manifolds, and similarly to connect the manifolds to the flowlines via a Flowline Termination Assembly (FTA) structure. The flowline jumpers are typically between 25 m and 100 m long with a diameter range between two inches and ten inches depending on which service. The jumpers are of a similar construction to flexible flowlines.
3.4.5
Risers
A total of 15 flexible risers are currently installed; when the new FPSO arrives on-station this will change to 21 flexible risers (an additional 5 production risers and 1 gas riser). Risers will be fitted with protection sleeves and buoyancy modules to raise them off the seabed to minimise damage caused by abrasion. Each newly positioned riser will require tethering to the seabed to minimise movement. Tethers are connected to piles and suction anchors, of which there are two per riser (one pile and one suction anchor (Figure 3.8)). It is anticipated that where existing risers are being replaced or laid down and then re-connected to the Page 3.13
The Development new FPSO, that piles and suction anchors currently in place will be re-used. However, the re-use of existing piles will depend on tests carried out to assess the current integrity of each pile, the results of which will determine whether any existing piles and suction anchors will need to be replaced. The 6 new risers will require the installation of additional piles and suction anchors (6 piles and 6 suction anchors). The installation of the new and any replacement piles will result in piling operations at the seabed near the new FPSO.
3.4.6
Umbilicals
There are currently 3 dynamic umbilicals installed.
When the new FPSO comes on-station this will change to 2 umbilicals (the 3 existing umbilicals will be removed, 1 will be repaired, re-tested and reinstalled, and 1 will be replaced with a new umbilical). It is possible that an additional dynamic/static power umbilical will be provided to accommodate any future subsea pumping facilities (see Section 2.5). However, this will not be installed in 2015 as it is only a potential option that may be considered in the future. Both static and dynamic umbilicals will be used to deliver the chemical, electrical, control and communication services to the new subsea wells. The umbilicals from the new FPSO will terminate at an Umbilical End Termination Assembly (UETA) located at the drill centre. This will
Figure 3.8: Typical riser and mooring configuration
Page 3.14
November 2010
The Development be connected to the drill centre Controls Distribution Assembly (CDA), which in turn connects to individual subsea control modules on the wellheads. The electro-hydraulic CDA enables a number of wells to be controlled by a single umbilical. Control of the subsea facilities and injection of chemicals will be undertaken from the new FPSO.
3.4.7
Subsea installation and commissioning
Seabed preparation and pre-installation survey Seabed preparation work will be required before the installation of subsea facilities and flowlines. Bathymetric and shallow soils data will be acquired by a suitable survey vessel in order to ensure the seabed is suitable for supporting the equipment. Core samples may be taken at the drill centre site to confirm soil strengths in order to design suitable structural foundations. Survey data will be reviewed before finalisation of any drill centre or flowline location to ensure there are no major obstructions on the seabed such as wrecks. Flowline and umbilical installation A specialist pipe lay vessel will carry out flowline and umbilical installation. A clump weight anchor is placed at either the drill centre or the FPSO, and the flowline or umbilical is then lowered and connected to the clump weight that acts as an end restraint allowing the lay vessel to pay out the pipe as it sails along the route. Once laid the route is visually inspected by ROV to confirm its location and identify any large spans. Span rectification, if required, is then carried out using grout filled bags or suitable mattresses and supports. The as-laid data are fed back to the onshore team for records and charts to be updated. Experience at Schiehallion indicates that span formation (and therefore rectification) is not common due to the relatively consistent seabed and detailed pipeline route selection procedures. Manifold, suction pile and flowbase installation The construction vessel will install all the manifold type structures and dependent on scheduling requirements may install the suction piles and flowbase and deflector base assemblies. The manifolds will be deployed to depth using the vessel crane, walked into their final position and then lowered onto the seabed. ROVs will be used to monitor the position and to disconnect the rigging. An as-installed survey will be completed before leaving the worksite.
November 2010
Tie-in infrastructure at drill centres The new wells will be tied into the production and water injection manifolds using existing ROV based tooling. The ROV mounted tooling and the Diverless Maintainable Clusters (DMac) connection system has been used to make over 600 successful connections at Schiehallion and Foinaven to date. The equipment for connection e.g. umbilicals or DMac, are initially positioned on the seabed and manoeuvred into position by a pull in tool, winches and an ROV. Tie-in infrastructure at the new FPSO Flexible flowline jumpers tied in using the ROV based tooling will connect the flowlines at the FPSO end. The control umbilical will be connected to the existing controls distribution system under the FPSO using controls umbilical jumpers, which are flown into position by the ROV and connected using the ROV mounted tool. An as-laid survey of all new equipment will be completed before leaving the worksite. Precommissioning After completion of flowline installation, precommissioning operations, including hydrotest and leak detection procedures, will be undertaken to ensure the integrity of the flowlines. A final as-laid or as-installed survey will also be undertaken prior to leaving the field and the details noted accordingly.
3.4.8
Inspection and maintenance
BP operates a risk-based Pipeline Integrity Management Scheme (PIMS) and this system will be used for design and implementation of an inspection and maintenance system for the new flowlines. Routine maintenance of flowlines consists of regular visual inspection of all flowline systems for integrity and the frequency of inspection is determined by the PIMS. If the inspection regime identifies any defects, then the necessary corrective maintenance will be performed (e.g. the use of corrosion inhibiting chemicals, or the replacement of the flowline). To date the flowlines at Schiehallion and Loyal have had no major issues in terms of integrity maintenance. Intelligent pigging will be routinely planned during the life of the flowlines using a risk-based methodology. Intelligent pigs are primarily used to measure wall thickness loss in order to determine the presence or extent of internal corrosion.
Page 3.15
The Development
3.5
3.5.1
Disconnection and reconnection of existing subsea infrastructure Overview
The current planned schedule is for removal of the existing Schiehallion FPSO in Q3 2014, with the arrival of the new FPSO in Q1 2015 and reconnection of the risers and dynamic umbilicals in Q2-Q3 2015 (see Figure 1.3). To facilitate this process, while maintaining system integrity, current subsea infrastructure will need to be suspended between 2014 and 2015. Although outside the scope of this EIA, the following sections provide an outline of the process involved in the disconnection of the Schiehallion FPSO in order to provide some clarification on the installation/reconnection of the new FPSO. It is anticipated that the removal and replacement process will require a working season in each of the years 2014 and 2015 to complete. A season runs from May to September although this may be extended depending on the weather conditions.
3.5.2
Well preservation during shutdown
In preparation for the removal of the existing Schiehallion FPSO, wells will be progressively isolated and methanol left between the DHSV and the tree valves in each production well.
3.5.3
Flowlines and umbilicals
The existing SURF infrastructure will be flushed clear of hydrocarbons and disconnected from the existing Schiehallion FPSO. It is anticipated that up to 7 of the existing risers will then be laid down in a pliant wave configuration on the seabed. However, the exact number of risers to be laid down and reused will depend on the outcome of integrity tests currently being carried out. The existing dynamic umbilicals will be recovered and one of them repaired in readiness for re-installation (Section 3.4.6). These activities together with the removal of the moorings (Section 3.5.4) will be followed by the removal of the FPSO from station.
3.5.4
Moorings and anchors
New suction anchors will be installed for the replacement FPSO moorings and these may be preinstalled, prior to removing the existing mooring lines. It is not proposed to remove the existing suction anchors and these will remain in-situ. Moorings for the existing FPSO will be removed at the same time as the risers and umbilicals. Where possible, existing piles and suction anchors will be reused for the risers. However, if this is not possible, the new risers will be tethered to new riser base piles and suction anchors (see Figure 3.8).
3.6
Floating Production Storage and Offloading (FPSO) vessel
3.6.1
General information
The new Quad204 FPSO vessel will replace the existing Schiehallion FPSO to allow further development of the Schiehallion and Loyal fields. The new FPSO will be designed for 25 years service and will measure 270 m in length and 52 m in breadth and have an operating draft of 14m to 20 m. The hull of the FPSO will be of double-sided, double-bottomed construction, and will be designed with enhanced fatigue performance and corrosion resistance suitable for service in a harsh environment. The new FPSO will have accommodation on board for 125 personnel, although it will be able to accommodate approximately 168 personnel during periods of high activity e.g. hook-up and commissioning and turnarounds (TARs). The living quarters will be located at the aft end of the FPSO and will be located at a sufficiently safe distance away from any hydrocarbon processing facilities. Table 3.7 provides a comparison between the dimensions of the existing Schiehallion FPSO and the new Quad204 FPSO.
Reconfiguration of existing drill centres and installation of 5 new flowlines is planned before the arrival of the new FPSO. The risers that have been laid down on the seabed will then be installed and fully commissioned after the new FPSO is brought on location and moored. The new risers and umbilicals, and those to be re-installed, will be connected, commissioned, fully leak tested and dewatered to the new FPSO.
Page 3.16
November 2010
The Development Existing Schiehallion FPSO
New Quad204 FPSO
Length
228.4 m
270 m
Breadth
45 m
52 m
Depth
27.25 m
30 m
Operating draft
12 – 20 m
14 m – 20 m
Hull
Double-sided Single-bottomed
Double-sided Double-bottomed
75 initially (increased to 123)
125 (168 during hook-up and commissioning and TARs)
Accommodation POB
Table 3.7: New and existing FPSO dimensions
The FPSO will be designed to collect production fluids from the wells and a number of process systems will be in place for subsequent treatment. An artist’s impression and layout of the FPSO is provided in Figure 3.10.
3.6.2
Installation and mooring
The new FPSO will be permanently moored in the field by a geo-stationary internal turret allowing the vessel to move freely according to sea state and wind direction. Mooring lines will run from the turret to a series of new suction anchors on the seabed (Figure 3.8). The existing FPSO has four bundles of mooring lines (2 bundles with 3 mooring lines each and 2 bundles with 4 mooring lines each) with a total
of 14 suction anchors installed. The new FPSO will require 20 new mooring lines and 20 new suction anchors similar in size to the existing anchors. The new mooring lines will be arranged in four bundles, with five mooring lines in each bundle. The suction anchors will be located at a slightly greater radius than the existing anchors (approximately 100 m further out) to allow installation without interference with the existing complex mooring system, prior to the removal of the existing vessel. As described in Section 3.5, the installation of the new FPSO will involve the re-attachment of existing umbilicals, risers and flowlines which will have been previously disconnected and left in-situ and the hook-up of any additional subsea infrastructure. The location of the turret in a forward position will allow the FPSO to weathervane passively without thruster assistance. The FPSO will have three aft thrusters on board. Thruster use will be restricted to the provision of assistance in close approach work e.g. heading control during offloading operations or in times of non co-linear wind, wave and current to damp vessel motions e.g. to minimise roll of the FPSO for oil separation and improve crew comfort. The base case will be for suction anchors for the mooring lines but some pile driving may occur where the substrate is such that suction anchors will not work effectively, the likelihood of which will be determined by geotechnical survey. At present the seabed information suggests that driven piles will not be required. However, if the future geotechnical
Figure 3.9: Simplified schematic of the new FPSO process systems
November 2010
Page 3.17
The Development survey identifies that suction anchors are unsuitable, then up to 20 new driven piles may be required.
Design Capacity
3.6.3
Existing Schiehallion FPSO
New Quad204 FPSO
Total fluids m /day (mbd)
50,200 (316)
50,900 (320)
Oil production 3 m /day (mbd)
35,000 (220)
20,700 (130)
Gas handling 3 sm /day (mmscfd)
3,964,300 (140)
6,230,000 (220)
Produced water 3 m /day (mbd)
35,800 (225)
49,300 (310)
3
Turret
The existing Schiehallion FPSO turret has 24 slots to accommodate risers and umbilicals. The new FPSO turret will have 28 slots that will be designed to have adequate space for process sub-systems and provide utility support for the subsea control system. The increase in the number of risers with the new FPSO will remove one of the bottlenecks to existing production. The turret arrangement transfers the produced fluids from the subsea wells to the production and/or test separation systems via multipath swivels in the swivel stack. The swivel system will be capable of handling various flow rates of produced and injected fluids and comprises: h Two production swivels to receive production fluids from the production manifolds (each swivel is sized for 65% of total production) h A test swivel to receive fluids from the test manifold (the test swivel is sized for 35% of total production) h Three gas swivels: two to supply gas for subsea gas lift and one to supply gas export or receive gas import via the WOSPS h Two water injection swivels to route injection water to the water injection risers h A utility swivel to route chemicals and control fluids to subsea and other fluids between the turret and topsides system h Electrical swivels to provide a range of different voltage rating supplies h Control and instrumentation swivels h Heating, ventilation and air conditioning (HVAC) swivels
3.6.4
Process facilities overview
The new FPSO will be designed to collect production fluids from the wells and a number of process systems are in place for subsequent treatment (Figure 3.9). The new FPSO will have a total liquids processing capacity of ca. 51,000 m3/day (320 mbd).
Table 3.8: New and existing FPSO design capacity
3.6.5
Oil production and well test system
Oil processing Produced fluids are routed via the production swivels to the slugcatcher where 2-phase (gas/liquids) separation occurs. Production fluids from the slugcatcher will be preheated prior to three phase (oil/water/gas) separation in two parallel 1st stage separators (Figure 3.11). Separated oil will then be heated before further three phase separation in a single 2nd stage separator. Final treated oil will be cooled before being routed to the cargo oil tanks. A three phase test separator will be provided which will include an upstream heater. Test facilities will facilitate well clean-up and well start-up operations as necessary. The system will be designed to ensure that blockage by solids does not occur during well clean-up operations and will enable the return of clean-up fluids to be segregated from the main production fluids where practical to minimise potential separation system upsets. The first stage separators and test separator will have fittings and accessories to allow for the possible future installation of a vessel internal electrostatic coalescer (VIEC) (See Section 2.5). The crude oil run down line to the cargo tanks will have inline compact electrostatic coalescers (CECs). The CECs will coalesce the remaining water droplets in the oil stream from the 2nd stage separator thereby enhancing the final stage of gravity separation in the cargo oil tanks.
Table 3.8 provides a comparison between the design capacity of the existing Schiehallion FPSO and the new FPSO.
Page 3.18
November 2010
The Development
Figure 3.10: Artist’s impression and layout of the new FPSO
November 2010
Page 3.19
The Development
This page has been deliberately left blank
Page 3.20
November 2010
The Development
Figure 3.11: Simplified schematic of separation train
Well testing Well testing will be necessary on the new FPSO to determine the performance of both new and existing production wells. A well test system is also required to enable allocation of production between the Schiehallion and Loyal fields on an individual well basis. The Quad204 Project will include a programme of drilling and well intervention, therefore, facilities will be required for the testing and clean-up of the new/refurbished wells as they are brought online. The base case for well testing and clean-up is the installation of a dedicated threephase test separator vessel on the new FPSO (see Section 2.4.4). It is anticipated that well testing will be undertaken on a monthly basis.
3.6.6
Produced gas system
Gas from the 1st and 2nd stage separators will be compressed in a single low-pressure (LP) compressor which will also compress the hydrocarbon gases displaced from the cargo oil tank and recovered flare gas. Gas from the LP compressor will be combined with gas from the November 2010
slugcatcher and routed to the high-pressure (HP) compression system. The HP compression system will include two parallel, equal capacity trains; each train consisting of 3 stages of compression. A common gas dehydration system will be provided to ensure that no free water forms downstream in the topsides, in subsea high-pressure gas lift, or gas export systems, and to meet gas export specifications. Produced gas will be used for fuel, with excess gas being exported via the existing WOSPS to the Sullom Voe Terminal (SVT). Gas export to the WOSPS will be via existing routes using the dedicated export/import gas riser and utilising existing subsea instrumentation. Where gas export is not available, gas will be reinjected into existing Schiehallion and Loyal production wells for gas lift purposes. The gas compression facilities will facilitate the significant lift gas volumes which are required due to the generally high production water cut. The gas compression design on the new FPSO 3 will be 6,230,000 sm /day (220 mmscfd) (Table 3.8). The new FPSO will also have a gas import facility installed which will enable gas import from the Page 3.21
The Development WOSPS should it be required during field start-up and shut-downs and future field gas deficiency.
h Controlled shutdowns (e.g. compressor shutdowns)
Flaring
h Emergency conditions (e.g. emergency blowdown)
Flaring of gas during normal operational conditions is not expected. A full flare gas recovery system will be included on the new FPSO which will remove all routine flaring including purge flows, pilots or leaks, which will be returned to the process system. However, the flare system on the new FPSO will be designed for the safe disposal of hydrocarbon gas during non-routine operations, including process upset conditions, for example:
h Pressure relief events (e.g. over pressure relief protection) To accommodate all releases to flare from process systems operating at different pressures, the flare system will require a HP and LP flare system (Figure 3.12). Gas from the 2nd stage separator and HP and LP
Figure 3.12: Simplified schematic of the HP and LP flare systems
Page 3.22
November 2010
The Development flare gas recovery vessels is often at too low a pressure to be routed directly to the HP compressors. As a result an LP compression system is required for operation of the flare gas recovery system. As the LP compression system is critical in order to avoid unnecessary flaring, and is vital for ensuring the operation of the flare gas recovery system, a two stage oil-free compressor with interstage cooling will be installed to ensure its reliability and availability (see Section 2.4.5). LP compression availability is also critical for the reduction of flaring volumes when flare gas recovery is offline, for example, during maintenance. When the flare, relief or blowdown discharge rate exceeds the flare gas recovery capacity (84,950 3 sm /day (3 mmscfd)) a suitable flare gas ignition system will be provided to avoid cold venting. Venting There will be a variety of minor sources of hydrocarbon gas vented from the new FPSO process systems, including hazardous drains vessels and the process heating medium vessel. Venting will also occur from the crude oil loading system and cargo tanks, slops and off-spec oil tanks. Cargo tanks, slops and off-spec oil tanks need to be maintained with an oxygen depleted atmosphere to avoid the build-up of flammable mixtures and prevent explosions. As a result the cargo oil tanks need to be blanketed by a non-oxygenated vapour. When crude oil is being loaded to the storage tanks from the process system these vapours are displaced. The new FPSO will be designed so that hydrocarbon gas is used to form a ‘blanket’ over the storage tanks (see Section 2.4.5). Displaced gas during the loading process will be compressed and routed to the flare gas recovery system, which is specifically designed to compress cargo tank vapours and return vented vapour to the produced gas system. An inert gas generator (IGG) system will be installed as a back-up when hydrocarbon gas is unavailable. The IGG will also be used for removing inert gas from the cargo tanks and subsequently supplying fresh air to the tanks prior to tank entry.
tanker.
3.6.7
Water systems
The production regime from the Schiehallion/Loyal area is characterised by significant water volumes which will increase over field life. Produced water comprises original formation water plus increasing quantities of injection water. The new FPSO will be designed to handle significant quantities (49,300 m3/day (310 mbd)) of produced water. Gravity separation equipment will be used for primary oilwater separation. Produced water which has been separated from the 1st and 2nd stage separators will be treated in deoiling hydrocyclones (Figure 3.13). Dissolved gas flotation will be used in combination with the hydrocyclones in order to meet a target maximum oil in water specification of 15mg/l. In addition to produced water from the oil separators, water stripped from cargo tanks and produced water routed to buffer storage will be returned to the topsides process through the produced water treatment system. Solids, mainly sand, will be removed from the produced water using desanding cyclones. Sand cyclones will be provided upstream of the deoiling hydrocyclones and upstream of the water injection pumps to provide protection against solids damage. Following clean-up all produced water will normally be re-injected to the reservoirs for reservoir pressure support, which will be supplemented with de-aerated seawater injection as required (Figure 3.14). Normal water injection capacity will be 60,400 m3/day (380 mbwd) with higher intermittent peaks of up to 90,600 m3/day (570 mbwd). The water injection system availability is a critical part of ensuring oil production is maintained. The produced water reinjection (PWRI) system will be designed so that the required minimum availability of 95% and a target availability of 98% can be achieved. In the case of any short term (2-4hr) system upsets the treated produced water will be routed temporarily to the off-spec cargo tank and recycled through the produced water treatment system once available. For longer term duration upsets the produced water will be routed overboard.
During the off-loading of crude oil from the FPSO to the shuttle tanker the inert gas in the shuttle tanker is displaced by the offloaded crude oil. VOCs generated during the offloading process will be recovered using specific process equipment onboard the shuttle tanker. The process unit onboard the shuttle tanker will enable the majority of the VOCs to be stripped before the gas is vented to atmosphere, with remaining VOCs/methane being used for fuel or to raise steam for use on the shuttle November 2010
Page 3.23
The Development
Figure 3.13: Simplified schematic of the produced water treatment process
Page 3.24
November 2010
The Development
Figure 3.14: Simplified schematic of the water injection system
As mentioned above, reservoir pressure support may be supplemented with seawater, particularly during production shutdowns/system upsets. The seawater, supplied downstream of the cooling medium coolers, will be filtered and de-aerated before being routed to the water injection pumps. Up to 30,200 m3/day (190 mbwd) (39,800 m3/day (250 mbwd at peak)) of seawater will be injected during system upsets. Metering and sampling points for produced water will meet OPPC regulatory requirements.
3.6.8
Sand treatment and disposal
Production fluids from Schiehallion and Loyal fields contain significant quantities of solids (primarily sands) and there is a risk that sand production will continue to increase over field life. The Quad204 project will install sand detection monitors on all new wells and sand detection in the topside risers will also be retained. Sand tends to deposit in major process vessels with finer particles being transported in produced water to November 2010
downstream systems. In order to maintain separation efficiency and protect rotating equipment, including pumps, sand must be removed from process streams. The existing Schiehallion FPSO has experienced a number of issues associated with sand. As a result the new FPSO will include a number of proven sand removal technologies with options for additional enhancements. Maximum facilities will be installed on the new FPSO with sand removal equipment being provided for the st nd slugcatcher, 1 stage separators, 2 stage separators, test separator, closed drains vessel, produced water treatment equipment, hydrocyclones and gas flotation package (see Section 2.4.4). Further details are provided below: h Sand removal from separation vessels on the new FPSO will be performed using cyclonic devices or an equivalent removal technology. The cyclonic device creates localised fluidisation of solids (the fluid will be produced water taken from the produced water booster pumps) and creates a vortex beneath the device which draws slurry into the discharge tube. The resulting slurry is transported to the sand clean-up package. Page 3.25
The Development h Sand will be removed continuously from the produced water using cyclone technology. Desanding hydrocyclones, which achieve solid liquid separation through radial forces exerted on the entering sand slurry, will be installed in the produced water line from the separation vessels and after the gas flotation unit. The desanding cyclones will each have an integral accumulator to collect the sand before periodically discharging it. h Oil/water hydrocyclone inlet chambers will be installed with a sand jetting system to remove any sand carried into these vessels. Sand will leave as slurry from the hydrocyclones and be transported to the sand clean-up package. h The gas flotation vessels will have an installed jetting system. The sand clean-up package (Figure 3.15) will consist of a single vessel containing a desanding cyclone with an integral accumulator vessel below. A slurry eductor pump will be required to remove sand slurry from the vessel during a cleaning cycle or when sand is being discharged overboard. The ‘motive’ fluid to be used for the clean-up package will be hot produced water. When a cleaning cycle is taking place the clean-up vessel will be unable to take sand slurry from any sources. The final sand clean-up configuration, including integration with the sand removal packages will be finalised during detailed design. Cleaned sand will be disposed of overboard in a slurry form via a dedicated disposal caisson combined with the use of best available techniques (BAT) for sand clean-up.
3.6.9
Utility systems
Power generation Power generation systems are critical to obtaining a high operating efficiency. The new FPSO will be self-sufficient in power generation, and the system comprises four duel fuel turbine generators with a total load requirement of 89 MW. Three of the turbines will be operational with one on standby as a non-running spare to ensure that gas compression facilities and PWRI systems can remain operational. Waste heat from the turbines will be used to provide the process heating requirements through the installation of waste heat recovery units (WHRUs). The turbines will be of high efficiency and able to be fuelled using either produced gas (normal operation) or low sulphur diesel. The turbines will also be dry low NOx emission (DLE) ready. Conventional liquid fuel combustion i.e. burning liquid fuels in gas turbines, involves the use of water and/or steam injection and can result in high levels of particulate matter e.g. NOx and CO. DLE means that when the turbines are operational and running on natural gas, emissions of NOx and CO are reduced to 25 ppm or less and do not require the addition of water. At each major overhaul of the turbines, BP will review legislation and technology readiness in considering implementation of DLE technologies (see Section 2.4.6). The new FPSO will have a gas import facility installed which will enable gas import from the WOSPS. This will make the new FPSO less reliant on diesel. There are two possible scenarios where the use of import gas may be required: h During field start-up and shut-downs (‘black starts’) when import gas will be used to kick-start the turbines and get processes back up and running as soon as possible
Figure 3.15: Simplified schematic of the sand clean-up package
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The Development h Future gas deficiency in the field where there is insufficient produced gas to run the turbines and gas is imported to compensate for this deficiency The monitoring of emissions from exhaust stacks and metering of fuel gas and diesel fuel rates will be available for each individual turbine. A secondary power generation system will be provided to secure reliable power supply in the event that the main generation systems fail. Three further generators will be provided for the provision of additional power. These include: h A dedicated emergency generator for emergency situations (diesel engine driven) h Two key services generators (diesel engine driven) The emergency generator will be capable of supplying electricity to critical services. In the event that the main turbines are shutdown, the key services generators will provide the starting power for the first main turbine. When necessary during production downtime, these generators will also be used for supplying the living quarters and key service utilities in preference to operating one of the main turbines. Chemical injection facilities A range of chemicals (to be held in bulk loading tanks) will be used in the operation of the process and utilities systems. Chemicals may be contained in closed systems e.g. as heating medium, or dependent on function, partition in whole or in part within the oil and water phase of the process system. Chemical injection facilities will be provided at various locations in the production system.
Anticipated chemicals likely to be used are discussed further in Chapter 7. Subsea and topsides equipment will be designed to ensure the controlled distribution of chemicals to each production well, in order to protect the trees and subsea pipelines. The following chemicals may be introduced into the well stream: hydrate inhibitor (methanol), wax inhibitor, scale and corrosion inhibitors and demulsifiers. Enhanced oil recovery system The new FPSO will be designed to include an enhanced oil recovery (EOR) system, which will comprise a loading system for emulsion based polymer, and facilities for storage, mixing and injection of polymer into the water injection system. EOR may be used to increase total oil production over the life of field without exceeding peak oil production. The decision to implement EOR is still to be made (see Section 2.5). EOR is not considered further in this ES. However, if EOR is implemented an addendum will be made to this ES at the appropriate time, if required (see Section 1.4).
3.6.10 Oil storage/export system Export quality crude oil will be stored in the main cargo tank block which will be segregated by two longitudinal bulkheads with a number of transverse bulkheads to provide a centre cargo tank and two cargo wing tanks across the FPSO mid-ship section. A single cargo tank will be designated for storing and separating off-spec oil. The FPSO will have facilities to export 111,465 m3 (700,000 bbls) of oil, with offloading of this amount taking place within a 24 hour period.
Figure 3.16: Example of the new FPSO tank arrangement
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The Development Total oil storage capacity will be approximately 172,560 m3 (1.08 million bbls) which is sufficient for a full export parcel, plus 2-3 days production ullage to allow for delays in export to the shuttle tanker. Figure 3.16 provides an example of the new FPSO tank arrangement. Each cargo tank will have two submersible cargo pumps which will be used to discharge oil from the tanks and for removing separated produced water from the bottom of the tanks. An oil export pipe will run aft to an export hose reel fitted at the stern of the new FPSO. Oil will be exported from the FPSO via tandem offloading to a dynamically positioned bow loading export shuttle tanker as per the current Schiehallion operation. The oil export process involves interface between the FPSO and the shuttle tanker. The shuttle tanker is attached to the stern of the FPSO by a hawser and the export hose is winched across on a messenger line. The export process is managed by operations personnel on the shuttle tanker and FPSO with an emergency shutdown and disconnect facility. Oil in the shuttle tanker will be offloaded at an onshore terminal or direct to market in Northern Europe. As mentioned in Section 2.4.3 the shuttle tanker will be equipped with specific process equipment to ensure the recovery of VOCs generated during the offloading process.
3.6.11 Other utility systems There will be a number of utility systems in place onboard the new FPSO which will provide functions to support process systems, personnel and to safely control discharges to the environment. Those with potential environmental interactions are described below: Drainage systems The drainage systems comprise closed drains, turret drains, open drains, bunding and scuppers, and slop tanks. Open drains refers to all drainage of liquids from deck or plated areas. Liquids from module open decks, equipment rooms and ship’s machinery spaces will be collected via open drains and recovered to the FPSO slops tanks where treatment will be carried out to recover oil and ensure that water achieves the required oil in water specification of 15 mg/l before being discharged overboard. In addition to open drains treatment the FPSO slops tanks will also recover water from crude oil tank washing. The closed drains system will handle hard piped Page 3.28
drains from hydrocarbon containing process equipment, and will be completely segregated from the open drains system. Run off from non-process areas will be drained directly overboard. Bunding and controlled disposal will ensure there is division between process and non-process areas. A seal pot arrangement at the overboard drain will collect any minor hydrocarbon spills for recovery. Grey water and sewage system Sewage facilities will include an integrated vacuum toilet and sewage treatment system. Waste water (treated sewage water) and grey water will be discharged overboard. Fire protection system The fire protection system will comprise three firewater pumps, which will supply all the active firewater systems around the new FPSO. In addition, a fresh water fire main will be provided within the accommodation block. Deluge water and foam will flow directly overboard.
3.6.12 FPSO commissioning There are three main phases to commissioning and start-up: onshore commissioning and performance testing; offshore hook-up and commissioning; and start-up. To help minimise offshore commissioning activities, the Quad204 Project aims to maximise the onshore commissioning of process, utility and marine systems so that all completions activities are undertaken onshore. Marine systems will be startedup for use during the towing and installation phase.
3.6.13 Inspection and maintenance The new FPSO will be designed with high inherent levels of integrity and minimum requirements for invasive work to maintain the integrity whether it is for maintenance or inspection. Planned maintenance turnarounds (TARs) will be scheduled on a regular basis and optimised during detailed design.
3.7
Decommissioning
Provisions for decommissioning and site restoration will be included in the design of all new facilities and infrastructure in accordance with BP policy, BP MPcp Decommissioning Guidelines and legislation. The new subsea facilities design will also allow for removal of subsea architecture in line with legislation, for subsequent possible re-use and recycling onshore. Dynamic umbilicals and risers that will not be re-used will be recovered in 2014 and disposed of using normal BP management November 2010
The Development processes. Subsea static umbilicals that are being replaced by new static umbilicals will be recovered at the end of field life. These will act as ‘hot spares’ during field production. Table 3.9 provides an overview of the decommissioning timetable
Item
Approximate timescale for removal
Existing dynamic umbilicals that will not be re-used
2014
Existing risers that will not be re-used
2014
Existing FPSO
2015
Remaining subsea infrastructure
End of field life
New FPSO
End of field life
Table 3.9: Decommissioning timetable
At the end of field life, a Decommissioning Programme will be produced and submitted to DECC for approval and decommissioning will be conducted to meet as a minimum the regulatory requirements in place at that time. It is likely that on the basis of DECC Guidance, all of the flexible risers and small diameter flowlines associated with the Quad204 development will require complete removal, as well as the subsea facilities, and this has therefore been allowed for in design of the subsea facilities and flowlines for the Quad204 Project. In addition the FPSO will be removed and the design of the Schiehallion and Loyal field facilities makes them particularly suitable for efficient and effective decommissioning. The overall decommissioning strategy for the Quad204 Project will be to ensure minimal impact on the marine environment and other sea users. Therefore, removal will be performed in such a way as to prevent any significant adverse effects; and comparative assessment of the options by which this could be achieved will be prepared as part of the Decommissioning Programme submission for the Schiehallion and Loyal Fields.
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4
The Environment
This chapter provides data on the key environmental sensitivities in the area of the Quad204 Project. A summary of the particular sensitivity(ies) of the environmental feature is provided in a box at the beginning of the appropriate section.
4.1
Introduction
It is important for any EIA that there should be an understanding of the environmental features on which the proposed project may have an influence or be influenced by. This section describes the main characteristics of the offshore marine environment with particular attention being given to areas that may be sensitive to or may affect the proposed project operations. The Quad204 Project is located within UKCS Blocks 204/20a, 204/25a, 204/25b, 205/16a and 205/21b approximately 130 km west of Shetland and 35 km southeast of the Faroe/UK median line (Figure 1.1). The area has been under development for more than 15 years and during this time, BP and other industry groups have undertaken a wide range of environmental baseline and environmental monitoring surveys in the area (see Section 4.4). This chapter has drawn on these data as far as possible. In addition to these seabed surveys, BP has increasingly made use of video footage and photographs collected by remotely operated vehicles (ROVs). Collaborating closely with key players in the oil and gas industry, the "Scientific and Environmental ROV Partnership using Existing industrial Technology" (SERPENT) project uses ROV technology and enables data to be more accessible to the scientific community, thus promoting the sharing of knowledge and effecting progress in deep-sea research (images from relevant SERPENT work are given in Section 4.4). ROVs have been used at Schiehallion and Foinaven as an active contribution to the SERPENT project. The programme works in partnership with science and conservation groups to communicate the project’s aims to the public, increasing the awareness of fragile marine resources. SERPENT is a global project hosted by the DEEPSEAS group, within Ocean Biogeochemistry and Ecosystems (OBE) at the National Oceanography Centre, Southampton (NOCS). The project has a network of UK and global partners, including BP. Data gained through the use of ROVs have increased understanding of November 2010
the deep water environment in the Quad204 Project area. Other environmental surveys undertaken by BP in the area, and which are used as data sources in this chapter, include: h Chlorophyll (phytoplankton) surveys at Foinaven h Acoustic monitoring of cetacean populations at Schiehallion and Foinaven h Direct marine mammal and seabird observations Some species mentioned in this chapter have been referred to by their common names, the corresponding Latin names are provided in the Glossary of Latin Names.
4.2
Hydrology
Environmental Sensitivity: The hydrology, current regime, waves and salinity are not particularly sensitive to offshore oil and gas activities. However, they are of importance in understanding the wider ecology of the area and the potential fate and effects of potential discharges and it is therefore important to understand how they may affect the project.
4.2.1
Bathymetry
The West of Shetland region can be described as being an extremely dynamic environment. The sea area to the west of Shetland can be divided into three main regions: the West of Shetland Continental Shelf (100 to 200 m depth), the West of Shetland Continental Slope (200 to 1,000 m depth) and the Faroe-Shetland Channel (>1,000 m depth). The Quad204 Project is sited on the continental slope in water depths of approximately 350 to 500 m. The seabed in the vicinity of the Quad204 Project exhibits a gentle slope downwards to the northwest.
4.2.2
Current regime
West of Shetland water mass movements can be simplified into ‘surface and upper’ currents and ‘lower and bottom’ currents. The West of Shetland surface layer is composed of North Atlantic Water (NAW), bounded on its western side by a frontal system which separates it from the cooler and slightly less saline water masses of the Modified North Atlantic Water (MNAW) and the Arctic Intermediate/North Icelandic Water (Figure 4.1). The predominant residual surface flow in the area is the North Atlantic Slope Current (AFEN, 2001) Page 4.1
The Environment which flows towards the northeast along the contours of the continental shelf edge, with mean surface current speeds in the region of 0.1 to 0.2 m/s (Kenyon 1986, Table 4.1).
of the various water masses (Hughes et al., 2003) along with large scale eddy currents and storm generated surges (Grant et al., 1995). Such sporadic water movement events can have an impact on seabed currents, increasing them by around 0.7 m/s for short periods of up to a few hours (BP, 2004); Metoc (2002) report that they may even increase up to 1.5 m/s and persist for several weeks. Current patterns in the area are complex with various strong non-tidal currents interacting with relatively weak tidal flow. These currents are influenced by the predominantly north east/south west water flow in the area (Figure 4.2), although this becomes less apparent as the current speed decreases with increasing depth. The tidal range in the area has a mean spring velocity of 1.5 m in Shetland and up to 3.0 m in Orkney (DTI, 2003).
4.2.3 Waves Figure 4.1: Water bodies of the Faroe-Shetland Channel
Depth (m)
Direction from (m/s)
The deep water over the West of Shetland continental slope is exposed to a large westerly fetch and strong winds (particularly from the west and southwest); these conditions generate an extreme wave regime in the area. The wave climate in the area is considered to be far more severe than the northern North Sea and significant wave heights exceed 2.5 m for 50% of the year and 4.0 m for 10% of the year (DTI, 2003). There has been a steady increase in significant wave heights of approximately 2 – 3 cm annually in the 30 years leading up to 2000 (AFEN, 2001).
N
NE
E
SE
S
SW
W
NW
Surface
0.07
0.24
0.12
0.04
0.07
0.24
0.12
0.04
100
0.07
0.23
0.12
0.04
0.07
0.23
0.12
0.04
200
0.07
0.22
0.11
0.04
0.07
0.22
0.11
0.04
250
0.06
0.22
0.11
0.04
0.06
0.22
0.11
0.04
300
0.06
0.21
0.11
0.04
0.06
0.21
0.11
0.04
4.2.4 Salinity and temperature
400
0.06
0.19
0.10
0.03
0.06
0.19
0.10
0.03
500
0.03
0.10
0.05
0.02
0.03
0.10
0.05
0.02
Mean sea temperatures range between 7.5°C in February and 13°C in August at the surface but can be as low as -0.5°C at 500 m water depth. At water depths of 500 – 600 m temperature variations of several degrees may occur over a matter of hours to days (Ferguson et al., 1997). During a 1996 survey (Hughes et al., 2003) a current meter moored to the seabed on the West of Shetland slope at a depth of 550 m recorded a temperature range of -0.8°C to 8.9°C. Sea-surface temperature has risen by between 0.5 and 1 °C from 1870 to 2007, although warming since the mid-1980s has been less pronounced in deeper waters than in shallower regions (UKMMAS, 2010). The mean salinity in the area varies annually, but is typically between 35.25 and 35.42 (BODC, 1998). UKMMAS (2010) report a slight increase in salinity in the northern regional seas, including that in which the Quad204 Project is located. A comparison of temperature and salinity for different water masses is shown in Table 4.2.
Table 4.1: Mean spring currents by direction (metocean data for the Quad204 Project area)
Within the water column, intermediate water masses separate the upper warm layer from the sub-zero lower water layers (Figure 4.1). Lower and bottom currents (below 500 m) consist of the cold Arctic basin water flowing southwards into the Faroe-Shetland Channel (Figure 4.2) where mean seabed current speeds are in the region of 0.05 to 0.1 m/s (although Metoc (2002) report that seabed currents in the Quad204 Project area are strong at around 0.3 m/s, with the 100 year extreme current speed being up to 2 m/s close to the surface). The boundary layer between these masses is occasionally disturbed for a number of hours by incursions of cold water called seabed surges which are strongest near the 500 m contour. Internal waves may also propagate the boundaries Page 4.2
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Figure 4.2: Currents around the Faroe-Shetland Channel
4.2.5 Water quality Water mass
Temperature (°C)
Salinity
North Atlantic Water
>7.5
>35.3
Modified North Atlantic Water
6.0 – 7.5
35.12 – 35.18
Arctic Intermediate/North Icelandic Water
3.0 – 4.5
34.95 – 35.00
Norwegian Sea Intermediate Water
0.25 – 0.75
<34.92
Faroe-Shetland Channel Bottom Water
<0.5
Not available
Table 4.2: Comparison of salinity and temperature (Heath & Jónasdóttir, 1999)
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The OSPAR Commission (2000) reports a scarcity of data as regards the levels of contaminants in northeast Atlantic waters. Extrapolation from the limited data available for the source water masses suggests that contaminant concentrations are at background levels (NSTF, 1993; OSPAR Commission, 2000). This is likely to be due to the lack of any direct pollutant sources and the prevailing ocean current system which will disperse and dilute any pollutants. Nutrient levels are found to be most elevated near the coast and around estuaries, where there is a high level of anthropogenic activity. In offshore areas, nutrient levels are reduced and are seen to vary primarily with the season.
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4.3
Meteorology
Environmental Sensitivity: The strength and direction of the wind can impact on the type of structure required for the project and the speed and direction of any possible discharges. The seasonal distribution of wind speed and direction is summarised in Figure 4.3. For much of the year (July through to March) winds from the south and west predominate. By contrast there is a greater evenness of wind distribution during the spring months (April to June), when winds originating from the ESE, NNW, N and NNE occur with a higher frequency than SW winds.
The predominant wind speeds throughout the year are from moderate to strong breeze (5.5 – 13.5 m/s) and these have an overall frequency of almost 50%. There is however a marked seasonal variation in wind speeds. Strong winds (exceeding 13.5 m/s) can occur throughout the year, however the frequency of strong winds is most prominent during the winter months (October through to March). In the summer months (July and August) wind speeds vary between light and moderate breeze (2 – 8 m/s). During the rest of the year (April to June and September to October) the wind speed fluctuates between 3.5 and 10.5 m/s. Calm conditions (less than 0.5 m/s) are rare, tending to occur only in July for brief periods of time only.
Figure 4.3: Seasonal wind speed and direction for the West of Shetland offshore area
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Figure 4.4: Environmental survey types
Winds can occur from any direction but the predominant winds throughout the year are from the south through southwest to west. These wind directions are particularly prevalent in late summer and through winter months (July to March).
4.4
Seabed sediments
Environmental Sensitivity: Potential discharges arising from the proposed project could impact on the sediments causing increased contamination in the vicinity of the proposed activities.
4.4.1 Sediment and seabed features A series of major regional surveys in the West of Shetland area were undertaken in the late 1990s and early 2000s; these include the Atlantic Frontier Environmental Network (AFEN) 1996 and 1998 surveys (both reported in AFEN, 2000), BIOFAR 1 and 2 (investigations of the benthic fauna of the Faroe Islands; BIOFAR, 2006), DTI 1999 White Zone and DTI 2002 Strategic Environmental Assessment (SEA) 4 surveys (DTI, 2003). These surveys have provided a broad overview of the benthic ecology of the Atlantic Margin area. In addition to these regional surveys, BP has undertaken a number of site-specific baseline and post-drilling surveys in the Quad204 Project area. Figure 4.4 summarises the benthic environmental surveys that have been undertaken in the Quad204 Project area. The location of the survey sample sites relevant to the Quad204 Project are shown in Figure 4.5. November 2010
Regional context The seabed sediment physiography of the West of Shetland shelf largely reflects the reworking by near-bottom currents of the sediments deposited since the glaciations (Holmes et al., 2003). The sedimentary characteristics consist of ice-rafted boulders and gravel in the southwest of the FaroeShetland channel to finer sediments in the northeast (Jones et al., 2007). There are two types of bed form found within the Quad204 Project area (Figure 4.6): h Iceberg ploughmarks; these are inactive features which are very common along the outer shelf and upper slope area in water depths ranging from 200 – 450 m (Masson, 2001; Stoker et al., 1993 and Fugro Geoteam, 2000). They are considered relict scars in the seabed with raised margins that were originally caused by the dragging of iceberg keels. Typical ploughmarks are several tens to a few hundred metres in width, are nowadays infilled with sediment, and the original raised margins may either remain evident in the seabed relief or be entirely buried. Seabed photographs show coarse gravel and stones in the ridge areas and finer material in the central grooves (AFEN, 2001). h Smooth featureless continental slope, below the 450 m contour (AFEN, 2001), with the sediments disturbed by slope failure and mass flow.
Page 4.5
The Environment Most of the deep-sea habitats (those which occur beyond the edge of the continental shelf in more than 200 m water, UKMMAS, 2010) are sedimentary, with rocky habitats and reefs largely confined to seamounts and similar structures (none of which have been identified in close proximity to the Quad204 Project area). In common with many subtidal areas, deep-sea habitats are vulnerable to the impacts of some anthropogenic activities, with some types of mobile fishing gears representing the main pressure (UKMMAS, 2010). The Quad204 Project area lies in an area dominated by iceberg ploughmarks (Masson, 2003; Fugro Geoteam, 2000), which are generally orientated in a northeast to southwest direction throughout the area. Iceberg ploughmarks are particularly prominent in the southeast of the Quad204 Project area, and become less frequent to the north and west in water depths greater than 400 – 450 m. Numerous trawl scars are recorded to the north and west (e.g. Fugro, 2003), and a number of boulders and seabed mounds with heights up to 1 m are also present. In the deeper waters to the northwest of the Quad204 Project area, the seabed sand veneer shows evidence of sediment transportation with the formation of ripples of approximately 0.1 m height and 30 m wavelength. This is in agreement with wide area survey results, which conclude that sediment mobilisation due to bottom currents is particularly active at water depths in excess of 500 m (Masson, 2003).
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Figure 4.5: Survey sample locations in the vicinity of the Quad204 Project
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Figure 4.6: Seabed features around the Quad204 Project area
Quad204 Project area Seabed surveys of the Quad 204 area (e.g. Fugro Geoteam, 2000, Fugro, 2003, Gardline, 2003), including those summarised in the BP review of the West of Shetland region (Aquatera, 2008), indicate that the surface sediment is a thin veneer of sand. Underlying sediments are very soft to firm (occasionally stiff) sandy clays and silty clays, with gravel and occasional pebbles (Figure 4.7). The surface sand is generally less than 0.1 m thick, but may be up to 2 m thick in the troughs and depressions interpreted as iceberg ploughmarks. Gardline (2002) reported that the seabed sediments at Schiehallion comprise gravelly sand with numerous cobbles and scattered boulders. The same survey noted numerous, well-defined anchor chain scars. Surveys undertaken by BP indicate that the surface sediments in the area are well oxygenated fine to coarse gravel and sand, with the majority of the sediments being characterised as medium sands (BP, 2000a). The sediment samples were classified as moderately well to poorly sorted sediments (BP, 2004). The most recent survey of the Foinaven and November 2010
Schiehallion fields indicated that sediments were poorly or very poorly sorted, comprising slightly gravelly muddy sand and sandy gravel (Gardline, 2007). The sediments were reported to be generally similar to or slightly coarser than sediments sampled during previous surveys in the area (Gardline, 2007).
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Figure 4.7: Seabed sediment characteristics
Seabed contaminants As outlined above, environmental data west of Shetland in the vicinity of the Schiehallion and Foinaven fields are available from both regional scale survey and monitoring (AFEN, 2000 and DTI, 2003) and from the various more detailed locationspecific surveys involving seabed grab sampling commissioned by BP around Schiehallion (BP, 2000a, 2000b; ERT, 2007) and Foinaven (ERT, 1999, 2000a, 2000b). To date, all of the sediment hydrocarbon data recorded in the area have been generated using a consistent measurement technique (gas chromatography; GC, and gas chromatographyPage 4.10
mass spectrometry, GC-MS) and therefore all the results should be broadly comparable. The same is not true for most of the data regarding sediment metals content, with the exception of total barium. Different extraction methods were used for other metals in the AFEN and DTI regional scale surveys and by Gardline (2007) compared to the previous location-specific surveys commissioned by BP, rendering direct comparisons impossible. Hydrocarbon results from previous survey work are summarised as total hydrocarbons (THC) and total polycyclic aromatic hydrocarbons (2-6 ring PAH) in Table 4.3, whilst metals results are summarised in Table 4.4 and Table 4.5 (total sediment digest methods and 50% nitric acid sediment digest methods respectively). November 2010
The Environment Reference
Survey
Total hydrocarbon concentration range (mg.kg-1)
Total 2-6 ring PAH concentration range (mg.kg-1)
AFEN (2000)
AFEN (1996)
0.5 to 11.2
0.015 to 0.238
AFEN (2000)
AFEN (1998)
1.0 to 6.5
0.056 to 0.116
DTI (2003)
Survey for SEA 4
0.8 to 11.0
0.005 to 0.519
BP (2000a)
Claw, May 2000
1.0 to 1.3
0.019 to 0.038
BP (2000b)
Schiehallion Central, May 2000
0.4 to 23.7
0.024 to 0.309
ERT (1999)
Foinaven, December 1998
3.1 to 50.7
0.051 to 0.089
ERT (2000a)
Foinaven, December 1998 & August 1999
1.2 to 17.1
0.035 to 0.092
ERT (2000b)
East Foinaven, August 1999
1.0 to 2.0
0.015 to 0.040
Gardline (2007)
Foinaven and Schiehallion, July 2007
0.5 to 2.4
0.045 to 0.139
Table 4.3: Sediment hydrocarbon concentration ranges
-1
Sediment metal concentration range (mg.kg ) Survey
Total Ba
Total Cd
Total Cr
Total Cu
Total Ni
Total Pb
Total Zn
AFEN (1996)*
84 to 1,116
<1
11 to 71
4 to 35
9 to 45
<2 to 39
11 to 88
AFEN (1998)*
319 to 824
<1
37 to 66
9 to 16
23 to 36
5 to 8
27 to 38
DTI (2003)
208 to 349
<1
10 to 35
2 to 39
5 to 34
3 to 20
15 to 76
Gardline (2007)
199 to 1,090
0.16 to 0.36
14 to 37
5 to 12
9 to 27
8 to 12
18 to 48
* both surveys reported in AFEN (2000). Table 4.4: Sediment hydrocarbon concentration ranges
-1
Sediment metal concentration range (mg.kg ) Survey
Total Ba
Cd
Cr
Cu
Ni
Pb
Zn
BP (2000a)
<500
0.07 to 0.18
<2
<1 to 3
<2
18 to 26
10 to 24
BP (2000b)
<500 to 8,550
0.09 to 0.20
<2
<1
<2
14 to 30
12 to 27
ERT (1999)
<500 to 3,270
0.03 to 0.04
8 to 17
6 to 9
6 to 12
6 to 11
22 to 32
ERT (2000a)
<500 to 6,560
0.04 to 0.09
8 to 29
2 to 18
7 to 28
7 to 26
23 to 63
ERT (2000b)
<500
0.08 to 0.09
7 to 11
1 to 8
5 to 12
6 to 15
23 to 75
Table 4.5: Sediment metals concentration ranges - surveys using ‘50% nitric acid’ digest method (‘total’ digest still used for barium)
The levels of THC measured during the regional AFEN and DTI studies (0.5 – 11.2 mg.kg-1) are November 2010
generally comparable with background concentrations reported for areas of the North Sea remote from drilling activities (DTI, 2003; Aquatera, 2008). Furthermore, levels of total 2-6 ring PAH Page 4.11
The Environment recorded in the same regional studies were typical of those found in marine sediments remote from centres of anthropogenic activity, and observed to consist of a range of biogenic compounds combined with a low level of petroleum-derived material. With regard to the more focused locationspecific studies, most (BP, 2000a, 2000b, Gardline, 2007) have shown similar or lower levels of hydrocarbons. Surveys showing higher concentrations of hydrocarbons included ERT (1999, 2000a) and BP (2000b) where THC values ranged from 17.1 to -1 50.7 mg.kg . Even these levels can generally be considered background for the area and are slightly lower than typical background levels in the North Sea (Aquatera, 2008). There was little or no direct relationship between hydrocarbon concentration and proximity to drilling centres in any of these surveys. In addition, THC concentrations were largely below the 50 mg.kg-1 hydrocarbon toxicity threshold identified in the UKOOA cuttings initiative (UKOOA, 2005). At Schiehallion central (BP, 2000b) the 2-6 ring PAH concentrations in the sediment samples ranged up to 0.309 mg.kg-1, and evidence of drilling fluid residues was detectable at stations where PAH concentrations were highest. Overall, in all surveys including the most recent (Gardline, 2007) the evidence from PAH analysis indicated mixed pyrolytic/petrogenic input of aromatic material from natural sources and from drilling operations. There were no clear spatial trends evident in the data collected and there has been no overall decrease or increase in hydrocarbon concentrations between surveys. The concentrations of trace metals recorded during The AFEN and DTI regional scale surveys were influenced by the various sediment types naturally present. Metals levels including those of barium were, in general, similar to those found in other uncontaminated offshore areas and considered background for the region. Similar results were evident from surveys around the Claw and East Foinaven drilling centres (BP, 2000a; ERT, 2000b), and from the most recent environmental survey covering both Foinaven and Schiehallion (Gardline, 2007). Older surveys around the Foinaven and Schiehallion centres found total barium concentrations in the sediments (indicative of the presence of drilling mud) ranging up to 8,550 -1 mg.kg . These concentrations were higher than AFEN background levels and the elevated values were all recorded within 500 m or 1,000 m of the drilling centres (at Foinaven and Schiehallion respectively). Sediment concentrations of the other trace metals associated with drilling discharges Page 4.12
(e.g. cadmium, copper, lead and zinc) tended to remain within typical background ranges, although there was evidence of a small concentration gradient at Foinaven for some of these at stations between 250 and 400 m from the drilling centre (ERT, 1999). The slightly elevated barium levels observed at some stations may arise from barium sulphate (or barite), used as a weighting agent in drilling mud. In this form it has been found that the barium is biologically unavailable and will have no measurable effect, in chemical terms, on the benthic fauna (Jenkins et al., 1989; Hartley, 1996; Neff, 2005). The environmental impact of other trace metals will depend on their concentration in the cuttings, which depends to some extent on the geological source of the barite. However, Neff et al. (1989) found that metals associated with drilling mud barite are virtually unavailable to marine organisms that might come into contact with discharged drilling fluids. Overall, the contaminant content of the majority of sediment samples from locations in the Foinaven and Schiehallion fields over the years has been similar to the background values found in wide area surveys of the west of Shetland area. Some very limited drilling-related contamination (primarily indicated by the presence of slightly elevated hydrocarbon and barium concentrations) was recorded in some samples located close to the major drilling centres (Aquatera, 2008). However it was also noted by both Aquatera (2008) and Gardline (2007) that contaminant levels were very low when compared to typical North Sea cuttings pile values, and that clear concentration gradients are lacking, which suggests that cuttings and contaminant deposition has been relatively uneven and patchy.
4.5
Benthic communities
Environmental Sensitivity: Seabed fauna are potentially sensitive to physical disturbance e.g. damage from anchors and the deposition of drill cuttings Regional context There have been a considerable number of surveys undertaken in the West of Shetland area to investigate the benthic ecology of the area around the Quad204 Project area (e.g. reported in AFEN, 2000; Bett, 2000; BP, 2000a; BP, 2000b; AFEN, 2001; Hartley Anderson, 2002; Fugro, 2003; Gardline, 2003; ERT, 2007; Gardline, 2007). There is good evidence that regional distributions November 2010
The Environment of benthic communities west of Shetland are strongly affected by sediment type and seabed features, water depth and water temperature. Faunal distributions therefore vary differently down-slope and along-slope (AFEN, 2001). Macrofaunal abundance and biomass varies with depth on the West of Shetland continental slope in a complex fashion, with peaks in biomass and abundance at 700 m and 300 – 400 m respectively (Bett, 2000). Along-slope variation can be linked to seabed features and, in the area of interest, this variation is dominated by the presence of iceberg ploughmarks in water depths of 200 – 400 m. There are local variations in benthic fauna in the different zones of iceberg ploughmarks. The relatively open sediment areas that mark the iceberg scour tracks frequently have extensive gravel cover and are dominated by irregular burrowing echinoids, whereas the iceberg track margins which appear to be marked by lanes of glacial erratics are dominated by cidarid urchins and a variable encrusting epifauna (Bett, 2001). Two distinct communities have been identified in the Faroe-Shetland Channel; suspension and filter feeders were found to dominate the southern section while the northern half was dominated by deposit feeders (Jones et al., 2007). The continental shelf and slope area is characterised by two main macrofaunal assemblages, which are approximately separated by the boundary between the north flowing warm North Atlantic waters and the deeper cold water flowing from the Norwegian Sea. The boundary area between these two main macrofaunal assemblages occurs in the 300 – 600 m depth range (within which the Quad204 Project lies), and benthic diversity appears to peak at these depths, which correspond with the greatest temperature variations (Hughes et al., 2003). Quad204 Project area Surveys undertaken in the area have reported that the sediments support a species-rich and relatively abundant macrofauna, dominated by numerous annelids (BP 2000a, 2000b), the most abundant of which are detailed below. For example, the surveys around Schiehallion (BP, 2000a) found that the fauna mainly consisted of annelids (47%), crustaceans (26%), molluscs (16%) and echinoderms (4%). This is broadly typical of macrobenthic communities in offshore soft sediments for the North East Atlantic area (e.g. Pearson et al., 1996). In addition to the macrofauna recorded quantitatively, there was also a small epilithic component present in the samples, mainly comprising sponges, bryozoans, spirobid polychaete worms and hydrozoans inhabiting the small stones on the seabed (BP, 2000a, 2000b). November 2010
Other epifauna reported from the region include the sea cucumber and a number of crab species (e.g. Lithodes spp.). Gardline reported the benthic faunal community within the Foinaven/Schiehallion survey area (Gardline, 2007) to be sparse with an average of 2 52 individuals and 25 taxa identified per 0.1 m , and typical of a deep water location. The ten most abundant species within the survey area included the polychaetes Galathowenia oculata agg; the crustaceans Ampelisca spinipes, undetermined Ampelisca spp., Haploops setosa and Haploops tubicola; the burrowing brittlestar Amphiura sp and the bivalves Astarte cf. sulcata, Limopsis aurita and Thyasira succisa. ERT (2007) reports the results of the Fugro (2003) survey of the Schiehallion North West Drill Centre (NWAD), stating that the macrofauna were of moderate to relatively high density. Although it was also reported that the number of taxa and individuals was very low when compared to previous surveys at Schiehallion Central, the faunal community was not considered to be a function of historic pollution or previous activities around NWAD (ERT, 2007). The majority of taxa found were typical for the area, although several species characteristic of faunal communities elsewhere at Schiehallion were not present at NWAD. The faunal community at NWAD appears to be free from the effects of pollution or significant disturbance from previous Schiehallion activities (ERT, 2007). The limited areas of hard substrata found in the Quad204 Project area (e.g. boulders) support epifaunal populations although species abundance is considerably lower than on similar substrata in shallower water depths; sponges (e.g. Geodia spp, Stryphnus spp), sea urchins (Cidaris cidaris, Echinus spp), sea cucumbers (Stichopus tremulus) starfish (Hippasteria phrygiana) and crabs (e.g. Chaceon affinis) and squat lobsters (Munida sp.) are abundant among the sessile epifauna (Hartley Anderson, 2002). Side scan sonar surveys and more recent surveys in the Quad204 Project area have not found the cold water coral Lophelia pertusa to be present, but it is known to occur to the west of Shetland and is widely distributed throughout the Atlantic Ocean. Previous small discoveries of L. pertusa demonstrate the potential for the species to exist in the region (see Section 4.12.1) but there are currently no known long-term colonies. Evidence from all the surveys undertaken in the area suggest that there are no species or habitats of conservation importance identified (under the UK’s Offshore Petroleum Activities (Conservation Page 4.13
The Environment of Habitats) Regulations 2001) in the region (Gardline, 2007). Although care must be taken when making quantitative comparisons between each of the localised seabed surveys and with the earlier wide scale AFEN surveys, due to differences in sampling methods in addition to spatial and temporal variations, in qualitative terms the macrofauna of the Quad204 Project area appears typical to that found at AFEN stations in the vicinity (BP, 2000a). A selection of images of mobile benthic fauna collected from the Schiehallion field as part of the SERPENT project (see SERPENT, 2010, for details) are shown below (Plates 1 to 3). In an environmental review, Aquatera (2008) reported that there was little evidence of major impacts to the seabed macrobenthic communities in the Quad204 Project area.
Plate 3: Sea star (Asterias spp) on subsea infrastructure © SERPENT Project 2006
4.6
Plankton and primary production
Environmental Sensitivity: Plankton are potentially sensitive to contamination from chemical or oil discharges.
Plate 1: King crab (Lithodes spp) © SERPENT Project 2006
Plate 2: Spikey sea cucumber (Stichopus tremulus) on the seabed © SERPENT Project 2006
The planktonic community consists of a range of plants (phytoplankton) and animals (zooplankton) which inhabit the water column. Phytoplankton are particularly important as they are primary producers and form the basis of the marine food chain, being consumed by many higher organisms including fish and some cetaceans. Seasonal changes in hydrographic and meteorological features give rise to a seasonal cycle of primary production by phytoplankton. The seasonal phytoplankton cycle is closely paralleled by zooplankton that feed on the phytoplankton. The composition and abundance of plankton communities varies throughout the year and is influenced by several factors, in particular sunlight and vertical mixing in the water column due to wind and currents. All these factors are at their optimum in the spring months, leading to a pronounced period of phytoplankton growth, known as the spring bloom. The size and the timing of the blooms may vary from year to year depending on local weather and oceanographic conditions. Chlorophyll measurements undertaken at the Foinaven field in 1997 showed a peak in primary production occurring in May (Heath et al., 2000) (Figure 4.8) followed by a sharp decline in June. Ocean colour data also show chlorophyll levels over the continental slope west of Shetland increasing in April to May (SeaWIFs, 2002). The main long-term data on phytoplankton distribution in the North Sea and North Atlantic come from the Continuous Plankton Recorder
Page 4.14
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The Environment
Figure 4.8: Primary production and copepod cycles in the Foinaven-Schiehallion area
(CPR) which has been deployed in the area since 1931. CPRs are towed by ships on their normal route of passage at a depth of approximately 10 m. CPR data have been collated for the North Atlantic as part of SEA 4. The data collected from these surveys allows long term changes, as well as seasonal cycles, in the plankton community to be identified. Table 4.6 presents the most abundant phytoplankton species collated from CPR data recorded in this region that occurred in over 5% of samples (DTI, 2003). UKMMAS (2010) report that plankton communities are not generally subjected to anthropogenic pressures, although significant changes in species have been recorded as a result of rising temperatures, which can have knock-on effects on foodwebs and marine ecosystems.
Rank
Phytoplankton
1
Ceratium fusus
2
Thalassiosira spp.
3
Chaetoceros (Hyalochaete) spp.
4
Ceratium furca
5
Chaetoceros (Phaeoceros) spp.
6
Rhizosolenia alata alata
November 2010
7
Ceratium tripos
8
Thalassionema nitzscioides
9
Rhizosolenia styliformis
10
Nitzschia delicatissima
Table 4.6: Ten most abundant phytoplankton species in the North Atlantic (DTI, 2003)
Robinson (1970) used CPR data to study the seasonal cycle of phytoplankton in the North Atlantic including waters to the west of Shetland. A general picture of Shetland shelf waters is of the spring bloom starting towards the end of April and peaking in May; this is followed by a sharp decline in June followed by a fairly consistent standing crop until September after which there is a sudden decrease to the winter minimum (Figure 4.9). The plankton community as a whole in the region is similar to that encountered in the North Sea, although some individual species differ in abundance. The planktonic assemblage is mainly made up of northern intermediate (mixed water) and neritic (coastal water) species. The phytoplankton species Thalassiosira spp is found in the area early on in the year. Such diatom populations tend to have peak blooms in May with a rapid die off in June, when they provide an Page 4.15
The Environment important contribution to the vertical flux of biogenic detrital material to the seabed. Following on from this, a bloom of dinoflagellates occurs around min-August. These annual cycles are weather and oceanographic dependant (Johns and Wooton, 2003). Zooplankton are divided into two distinct groups – meroplankton, which refers to members of the plankton community that have a pelagic larval stage and a benthic adult stage, and holoplankton, which refers to organisms that are entirely planktonic. The zooplankton contains representatives from a range of taxonomic groups, from protozoans to larval fish, and all sizes from microscopic to large jellyfish. Zooplankton are dependant upon phytoplankton as a food source and therefore show a similar temporal distribution pattern. Zooplankton are not restricted to the photic upper layers of the water column and as a rule undergo diurnal vertical movement, moving towards the surface to feed at night and sink during daylight hours. Large populations of the herbivorous zooplankton Calanus finmarchicus over-winter in the cold deep waters of the Faroe-Shetland channel and come to the surface during spring. Sampling undertaken approximately 3 km west of Schiehallion indicates peak biomass of C. finmarchicus in summer months (July – August). Another copepod species,
Calanus helgolandicus, is also found in waters in the region. This species generally has a greater abundance further south in the warmer Atlantic water of the Rockall Trough area. However, a clear north-south split between these two species is not seen, and there is overlap in distribution. Calanus are an important food source for many fish species, notably herring and mackerel, and is therefore an important element in the recruitment of fish stocks over the continental shelf and slope. A number of parallel plankton sampling programmes were conducted at sites around the northeast Atlantic and Norwegian and North Seas (included Foinaven) in 1997 to fill in some of the gaps in the understanding of annual plankton cycles in the Atlantic Margin area. The TransAtlantic Study of Calanus (TASC) programme found Calanus finmarchicus to be less abundant in the eastern North Atlantic where the decline was strongest and most significant (west of UK only contributing to 10 – 40%). Reid et al. (2001) have suggested a link between increased temperatures in the slope current with a decline in C. finmarchicus. Other small copepods, crustacean larvae, decapod larvae and echinodermata larvae are also present in the area, along with the macrozooplankton euphausiids (krill) (BP, 2004).
Figure 4.9: Primary production in the north east Atlantic for CPR survey areas
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4.7
Fish populations
Environmental Sensitivity: Juvenile and adult fish species present in the area around the Quad204 Project are potentially sensitive to chemical and oil discharges. Demersal laid fish eggs are particularly sensitive to seabed disturbance during spawning seasons.
4.7.1
Species in the Quad204 Project area
Fish and shellfish populations can be categorised as pelagic (mid-water fish that often form shoals and make extensive migrations between different sea areas e.g. herring and mackerel) or demersal (fish that live on or close to the seabed e.g. plaice, cod and haddock) (Table 4.7).
4.7.2
Pelagic species
Pelagic fish are most commonly found in shoals swimming in midwater where they make extensive migrations between sea areas. The extent and timing of these migrations are linked to the hydrographic regime of the area, in particular the Continental Shelf Current. Pelagic species common in the area include mackerel, herring, blue whiting and the greater silver smelt. A number of pelagic sharks may also be present in the area including the porbeagle and the basking shark (Cetorhinus maximus). Some of these species spawn in the vicinity of the Quad204 Project or use the wider area as a nursery ground (Figure 4.10 and Figure 4.11), although the immediate Quad204 Project area is not widely used.
Demersal Fish Species
Black Scabbard (Aphanopus carbo)
Blonde Ray (Raja Brachyura)
Blue Ling (Molva dypterygia)
Bluemouth (Helicolenus dactylopterus dactylopterus)
Brill (Scophthalmus rhombus)
Catfish (Anarhichas lupus)
Cod (Gadhus morhua)
Common dab (Limanda limanda)
Conger Eel (Conger conger)
Greater forkbeard (Phycis blennoides)
Greenland halibut (Reinhardtius hippoglossoides)
Haddock (Melanogrammus aeglefinus)
Hake (Merluccius merluccius)
Halibut (Hippoglossus hippoglossus)
John Dory (Zeus faber)
Lemon sole (Microstomus kitt)
Ling (Molva molva)
Megrim (Lepidorhombus whiffiagonis)
Monkfish (Lophius spp)
Plaice (Pleuronectes platessa)
Pollack (Pollachius pollachius)
Porbeagle (Lamna nasus)
Portuguese Dogfish (Centroscymnus coelolepis)
Rabbitfish (Chimaera monstrosa)
Red gurnard (Aspitrigla cuculus)
Red mullet (Mullus surmuletus)
Redfish (Sebastes spp)
Roughead grenadier (Macrourus berglax)
Roundnose grenadier (Coryphaenoides rupestris)
Saithe (Pollachius virens)
Sea bream (Spondyliosoma spp)
Silver scabbard (Lepidopus caudatus)
Skates and rays
Sole (Soleidae spp)
Spurdog (Squalus acanthias)
Torsk (Brosme brosme)
Turbot (Scophthalmus maximus)
Whiting (Merlangius merlangus)
Witch (Glyptocephalus cynoglossus)
Pelagic Fish Species
Tope (Galeorhinus galeus)
Greater silver smelt (Argentina silus)
Horse mackerel (Trachurus trachurus)
Mackerel (Scomber scombrus)
Herring (Clupea harengus)
Table 4.7: Species caught in ICES rectangle 49E5 and 49E6 in 2009 (Scottish Government personal communication, 2010)
November 2010
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The Environment
Figure 4.10: Spawning areas in the vicinity of the Quad204 Project
The area is not considered as an area of high importance for most species, with only Norway pout spawning in the immediate vicinity of the Quad204 Project area and the same species being one of only a few (others include mackerel and blue whiting) the only one to use the area as a nursery ground. Norway pout (Trisopterus esmarkii) are found throughout the area and form an important part of the food chain for many commercial species such as cod and haddock. Norway pout are known to spawn around the Faroes and to the west of Orkney and Shetland.
Page 4.18
Spawning occurs between March and May in deep waters and between January and April over the continental shelf (Coull et al., 1998). Blue whiting nursery areas extend across the Faroe-Shetland Channel to the West of Shetland continental shelf (Coull et al., 1998 and McFadzen and Cook, 1996) and occur over the area in which the Quad204 Project is located (Figure 4.11).
November 2010
The Environment
Figure 4.11: Nursery areas in the vicinity of the Quad204 Project
Sandeels (Ammodytes spp) are abundant in the waters around both Orkney and Shetland during the summer months and are an important food for many commercial species (e.g. cod) and many seabirds (e.g. guillemots, kittiwake and Arctic tern) (Wright and Bailey, 1993). In the winter months, sandeels move into deeper waters (Muus and Neilsen, 1999). Sandeels are a pelagic shoaling species which remain buried in the sand during the
day, but occur in large shoals in the evening and early morning. Sandeels spawn to the south of the Quad204 Project area between the months of November and February (Figure 4.10). The Quad204 Project area lies across an important mackerel migration and wintering area. Following spawning, most of the population of adult mackerel migrate through the West of Shetland area to
Table 4.8: Temporal extent of spawning periods in the vicinity of the Quad204 Project (Coull et al., 1998)
November 2010
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The Environment summer feeding grounds in the Norwegian Sea and northern North Sea (Belikov et al., 1998 and Reid et al., 1997). This northerly migration occurs along the continental shelf edge. Parts of the migrating mackerel population will enter Orkney and Shetland waters at the time of the northerly migration and remain throughout the summer months (Robson, 1997a). Mackerel are most abundant over the continental shelf and in Shetland coastal waters on their return migration (Robson, 1997b). The timing of the migration has become later in the year over the last 20 years, with its peak shifting from August in the 1970s and early 1980s to January in the late 1980s onwards (Walsh et al., 1995).
4.7.3
Demersal species
The Quad204 Project area lies in water depths of between 350 and 500 m and demersal species in the area are characterised by both deep water benthopelagic species at their upper reaches and species regarded as typical of the continental shelf at the lower limits of their range (Table 4.9).
Deep water benthopelagic species
Continental shelf species
Silvery pout (Gadiculus argenteus)
Cod
Monkfish (Lophius piscatorius)
Saithe
Tusk (Brosme brosme)
Ling
Blue ling (Molva dypterygia)
Megrim
Red fish
Dab (Limanda limanda)
Greenland halibut
Spurdog (Squalus acanthias)
Roughhead grenadier
Starry ray (Raja radiate)
Arctic skate
Thornback ray (Raja clavata)
Greenland shark (Somniosus macrocephalus)
Haddock
Lemon Sole Plaice
No demersal species are known to spawn in the Quad204 Project area. The transition zone between upper warmer North Atlantic water and the deep cold water (at approximately 300 to 500 m water depth) supports a number of commercially important species, including the Greenland halibut, roughhead grenadier (Macrourus berglax), Arctic skate (Amblyraja hyperborea) and the deep water redfish (Gordon, 2003 and SAMS, 2001). Structures related to the existing infrastructure of the Quad204 Project act as a refuge for a number of species, in particular monkfish, redfish, cod and ling. A number of photographs captured of demersal fish in the Schiehallion field as part of the SERPENT project are shown below (Plates 4 to 6). UKMMAS (2010) report that the status of many benthic species has improved since the 1980s as a result of reductions in fishing effort, although communities demonstrate significant deterioration compared to historical conditions. The main pressures on these species are removal through commercial fishing activities and changes to species distribution and composition as a result of changes in water temperature.
Page 4.20
Table 4.9: Demersal species found in the vicinity of the Quad204 Project (Knijn et al., 1993, Daan et al., 1990 and Muus & Nielsen, 1999, Gordon, 2003)
Plate 4: Cod (Gadus morhua) investigate an ROV © SERPENT Project 2006
November 2010
The Environment The temporal and spatial distribution of seabirds is largely influenced by their lifecycle. The point at which birds are in their cycles will determine whether they are concentrated around breeding colonies or more widely dispersed over offshore waters. The distances that birds will travel from their colonies for food varies greatly between species and this influences offshore distribution. Twenty three species of seabird (including seaduck and divers) are known to breed on the coasts of the Western Isles, Orkney and Shetland Islands and a further 25 species are known to occur, at least occasionally, in the wider area at various times of the year (Reid et al., 2001). Plate 5: Redfish (Sebastus spp) © SERPENT Project 2006
4.8.2 Distribution and abundance There have been declines in the abundance of some species of breeding seabirds in north and north-west Scotland where the main pressures are considered to be climate change and the introduction of non-indigenous species (e.g. rat and mink affecting nesting sites) (UKMMAS, 2010). Changes in the North Sea plankton community in the late 1980s caused by rising sea temperatures has led to large reductions in abundance of the zooplankton on which larval fish feed and poor sandeel productivity is associated with warmer sea-surface temperatures (UKMMAS, 2010). Fisheries may also have contributed to a reduction in sandeel availability and quality (UKMMAS, 2010).
Plate 6: Monkfish (Lophius spp) © SERPENT Project 2006
4.8
Seabirds
Environmental Sensitivity: Seabird populations are particularly vulnerable to surface pollution. The vulnerability of bird species to oil pollution varies considerably throughout the year and is dependent on a variety of factors, including time spent on the water, total biogeographical population, reliance on the marine environment, and potential rate of population recovery. Species considered most vulnerable to sea surface pollution are those which spend a great deal of time on the sea surface, e.g. puffin, guillemot and razorbill. Species considered to be at lower risk due to spending less time on the sea surface include gannet, cormorant and kittiwake.
4.8.1
Introduction
Seabirds are an intrinsic element of the ecology of the West of Shetland area and are important indicators of environmental conditions. November 2010
Data on the distribution and abundance of seabirds in the UK and northwest European waters have been collated by the Joint Nature Conservation Committee’s (JNCC) Seabirds at Sea Team (SAST) since 1979, with the most intensive survey coverage occurring since 1994 (Pollock et al., 2000). Seasonal distribution of seabirds in the Quad204 Project area is given in Table 4.10. A total of 48 species of seabirds have been recorded from the SAST surveys and include fulmar (Fulmarus glacialis), storm-petrel (Hydrobates pelagicus), gannet (Morus bassanus), Arctic skua (Stercorarius parastiticus), great skua (Catharacta skua), herring gull (Larus argentatus), lesser blackbacked gull (Larus fuscus), great black-backed gull (Larus marinus), black-legged kittiwake (Rissa tridactyla), guillemot (Uria aalge), razorbill (Alca torda) and puffin (Fratercula arctica). Eight of these species are present all year round: fulmar, gannet, herring gull, great black-backed gull, kittiwake, common guillemot, razorbill and puffin. Although there is some variation across seabird species, overall, seabird densities are generally higher in nearshore waters than in offshore waters and during the summer months than during the Page 4.21
The Environment winter months. The fulmar is the most abundant species in the Quad204 Project area, whilst kittiwakes and puffins can occur in moderate to high densities at certain times of the year, particularly during March (before returning inshore in April to breed) and summer
months. Storm petrels occur widely throughout the area with peak densities occurring during August. Most other species of seabird including gannet, auks and skuas occur mainly at relatively low densities within the project area.
Species
January - April
May - July
August - September
October - December
Overall vulnerability to oil pollution
Northern fulmar
High densities
Moderate to high densities
Low densities present in deep waters greater than 200 m
Low densities
Moderate vulnerability due to aerial nature of large population and widespread distribution
Low densities
Low densities
Moderate vulnerability due to aerial nature of population
Very low densities of birds found over the area at this time
Very high vulnerability due to low breeding output, long period of immaturity and time spent on water (especially after the breeding season)
Black-legged kittiwake
During April birds are known to leave colonies to form breeding pairs Highest densities recorded over the continental slope in early spring In late spring birds begin to return to inshore breeding colonies
Mainly associated with fishing vessels
Not distributed in deep waters Remain close to coastal breeding colonies
Disperse from breeding colonies
Associated with fishing vessels at this time of the year Atlantic puffin
Common guillemot
European storm petrel
Very low densities of birds found over the area
Low densities
Low to moderate densities These are more likely to be nonbreeding birds as breeding birds at this time are found to feed in inshore coastal waters Low densities Birds at this time are present in high concentrations in inshore waters
Low densities Birds at this time are concentrated to the south of the Faroes and in the North Sea
For the majority of the winter months the birds are widely dispersed in the North Sea and into the Atlantic
Widespread at low densities in the area
Low densities occur in the area
Birds at this time are moulting in large congregations in inshore waters
Dispersed from breeding colonies
Birds migrate south over the winter months and are therefore not expected to be present
Low densities
High densities
High densities
Birds begin to return from southern wintering grounds
Birds at their greatest density during July
Population in August is widespread throughout the region with high numbers being found in the area Birds begin to migrate south in September
Northern gannet
Low densities
Low densities
Low densities
Adults begin to move back to the area after spending the winter in Africa
Immature birds begin to move back to the area
Become less widespread in September as they begin to migrate south
Birds disperse away from the colonies and may occur along the shelf-break
Very high vulnerability due to time spent on water and at-sea moulting
Moderate vulnerability Present in internationally important numbers during the breeding season
High vulnerability due to low breeding output and long period of immaturity
Table 4.10: Seasonal distribution of seabirds in the immediate area of the Quad204 Project area (adapted from Pollock et al., 2000)
Page 4.22
November 2010
The Environment 4.8.4 4.8.3 Seabird vulnerability The seasonal vulnerability of seabirds to surface pollutants in the Quad204 Project area has been derived from JNCC block specific data (JNCC, 1999). Offshore species that are most vulnerable are those that spend a great amount of time on the sea surface (such as the puffin and guillemot), while more aerial species such as fulmars, gannets and kittiwakes are of lower vulnerability. Birds that inhabit the offshore waters in the North Sea are exposed to a range of risks from oil and gas activity. The main potential risk to birds is from surface oil pollution, which can cause direct toxicity through ingestion, and hypothermia as a result of birds’ inability to waterproof their feathers should they become covered with oil. Due to differences in behaviour and distribution, the threat from hydrocarbon pollution varies with species. Species such as guillemots are at high risk from surface pollutants because they spend much of their time on the surface of the sea. Several species undergo a total moult of their flight feathers at some point during the year, during which they cannot fly. These birds are therefore confined to the surface of the water during this time, and this significantly increases their vulnerability to oil pollution, for example auks. Seasonal vulnerability of birds to oil pollution within the vicinity of the Quad204 Project is presented in Table 4.11 and is derived from the JNCC ‘offshore vulnerability index’. The data suggest that bird vulnerability to surface pollution will be high in March, May, June and September and moderate or low for the remainder of the year. At no points is vulnerability classified as very high and overall vulnerability for 204/20 and all surrounding blocks is low.
Migrating species
The UK lies on some of the major migratory flyways of the east Atlantic, with large numbers of water birds attracted each year by the relatively mild winter climate and extensive estuarine and wetland habitats (DECC, 2009b). DECC (2009b) report that large numbers of birds cross the North and Irish Sea during the spring and autumn migrations on their way between breeding and wintering grounds. These birds include passerines, near passerines, raptors and owls. It is reported that there appear to be no fixed corridors preferred by the migratory birds and migration usually takes the form of a broad-front (DECC, 2009b). Migration can be temporally variable and flight heights will vary depending on the species and weather conditions involved; this can range from just above the water surface to several thousand metres (DECC, 2009b). DECC (2009b) report the presence of four migrant seabird species in the Faroe-Shetland Channel region, these being the great shearwater (Puffinus gravis), long-tailed skua (Stercorarius longicaudus), pomarine skua (Stercorarius pomarinus) and sooty shearwater (Puffinus griseus). Non seabird species migrate through the area each spring and autumn to and from their breeding grounds, mainly in the Faroe Islands, Iceland and Greenland. Table 4.12 lists the most likely species to occur in the area during migration. Although the species may occur in the area during migration, the majority of them will not spend any time on the sea surface. The islands off the west and north coasts of Scotland are of importance for migrant waterfowl in spring and autumn since they lie on the major migratory flyway of the east Atlantic (DECC, 2009b). Many waterfowl, especially geese, can be found on passage or overwintering in the region (DECC, 2009b). The importance of the
Table 4.11: Block specific seabird vulnerability to surface pollution (JNCC, 1999)
November 2010
Page 4.23
The Environment region may increase during periods of severe cold further east in Scotland and continental Europe when there may be influxes of waterfowl into the region. It should be noted that coastal wetlands with saltmarsh or grazing marsh in close proximity to intertidal areas act as the key feeding and roosting areas (DECC, 2009b).
Species
Conservation 4 Status
Barnacle goose (Branta leucopsis)
Amber
Dunlin (Calidrus alpina)
Red
Golden plover (Pluvialis apricaria)
Amber
The islands to the south and east of the Quad204 Project area offer extensive and varied breeding habitats for seabirds. The main breeding seabird colonies around this region of the Atlantic Margin are illustrated in Figure 4.12 and in Table 4.13.
Greylag goose (Anser anser)
Amber
Knot (Calidrus canuta)
Amber
Lapwing (Vanellus vanellus)
Red
Between 2000 and 2008, changes in the population size of 19 of the 25 species covered by the UK seabird monitoring programme that breed in the UK have resulted in an overall decrease of approximately 9% (JNCC, 2009a). Of the seabird species breeding in the UK, only northern gannet and great skua have sustained an upward trend in population size from 1969 to 2008 (JNCC, 2009a).
Meadow pipit (Anthus pratensis)
Amber
Oystercatcher (Haematopus ostralegus)
Amber
Pied wagtail (Motacilla alba)
Green
Pink-footed goose (Anser brachyrhynchus)
Amber
Purple sandpiper (Calidrus maritima)
Amber
Snipe (Gallinago gallinago)
Amber
Razorbill (Alca torda)
Amber
Red-throated diver (Gavia stellata)
Amber
Redwing (Turdus iliacus)
Red
Scaup (Aythya marila)
Red
Snow bunting (Plectrophenax nivalis)
Amber
Tufted duck (Aythya fuligula)
Amber
Turnstone (Arenaria interpis)
Amber
Wheatear (Oenanthe oenanthe)
Amber
Whooper swan (Cygnus cygnus)
Amber
4.8.5 Breeding colonies
Table 4.12: Non seabird species regularly occuring through the West of Shetland region (Wernham et al., 2002, RSPB, 2009)
4
Status designated by RSPB (2009) under the terms ‘Red’, ‘Amber’ and ‘Green’.
Page 4.24
November 2010
The Environment
Figure 4.12: Seabird breeding colonies around the Atlantic Margin
a) Shetland
Ramna Stacks/Gruney
3
Fetlar
4
Ronas Hill and North Roe
5
Papa Stour
6
Foula
●
7
Noss
●
8
Mousa
9
Sumburgh Head
●
10
Fair Isle
●
November 2010
●
●
Shag ●
●
-
●
Arctic skua
●
-
● ● ●
●
●
●
●
●
●
●
●
●
●
●
Others
2
●
Storm Petrel
●
Leach’s Petrel
●
Puffin
●
Great skua
Kittiwake
Hermaness/Saxa Vord
Razorbill
Gannet
1
Guillemot
Colony name
Arctic tern
Site no.
Fulmar
Primary species for which important
●
Shag, Arctic skua ●
●
●
●
●
●
●
-
●
●
●
Shag, Arctic skua
Page 4.25
The Environment b) Orkney
14
Rousay
15
Marwick Head
16
Auskerry
17
Copinsay
●
●
●
18
Hoy and South Walls
●
●
●
19
Pentland Firth Islands
● ●
●
●
●
●
●
●
Others
Calf of Eday
Storm Petrel
13
Leach’s Petrel
Westray
Puffin
12
Great skua
Papa Westray
Kittiwake
11
Gannet
Colony name
Fulmar
Site No.
Razorbill
Guillemot
Arctic tern
Primary species for which important
Arctic skua, black guillemot ●
●
Arctic skua
●
Cormorant
●
Arctic skua
●
-
●
●
Great black backed gull
●
●
Arctic skua, great black backed gull
●
-
c) North Scotland, Western and Offshore Isles/Skerries
23
Cape Wrath/Clo Mor
●
●
Others
●
Storm Petrel
North Rona/Sula Sgeir
●
Leach’s Petrel
22
●
●
Puffin
Sule Skerry/Sule Stack
●
Great skua
21
●
Razorbill
●
Guillemot
North Caithness Cliffs
Common tern
20
Kittiwake
Colony name
Gannet
Site No.
Fulmar
Primary species for which important
●
Shag
●
●
●
Great black backed gull
●
●
Great black backed gull
●
●
●
●
●
●
●
●
-
Table 4.13: Important seabird colonies around the Atlantic Margin (adapted from Pollock et al., 2000)
Page 4.26
November 2010
The Environment Data on bird species of conservation concern which have been recorded in the area are given in Table 4.14.
Species
Conservation status
Northern fulmar
Amber
Reason for Status Breeding Population Decline; and Localisation (At least 50% of the breeding population found in 10 or fewer sites).
Black-legged kittiwake
Amber
Breeding Population Decline; and Localisation (At least 50% of the breeding population found in 10 or fewer sites).
Atlantic puffin
Amber
Categorised as a Species of European Conservation Concern; and Localisation (At least 50% of the breeding population found in 10 or fewer sites).
Northern gannet
Amber
At least 20% of the European breeding population found in the UK; and Localisation (At least 50% of the breeding population found in 10 or fewer sites).
Common guillemot
Amber
At least 20% of the European breeding population found in the UK; and Localisation (At least 50% of the breeding population found in 10 or fewer sites).
European storm petrel
Amber
Localisation (At least 50% of the breeding population found in 10 or fewer sites).
Great skua
Amber
Localisation (At least 50% of the UK breeding population found in 10 or fewer sites); and International importance (At least 20% of the European breeding population found in the UK)
Arctic skua
Red
Breeding Population Decline (Severe decline in the UK breeding population size, of more than 50%, over 25 years)
Leach’s petrel
Amber
Categorised as a Species of European Conservation Concern; At least 20% of the European breeding population found in the UK; and Localisation (At least 50% of the breeding population found in 10 or fewer sites).
Table 4.14: Bird species of importance in the vicinity of the Quad204 Project area (RSPB, 2009)
4.9
Marine mammals
Environmental Sensitivity: marine mammals are sensitive to both underwater noise generated from a range of installation and operational activities and potentially toxic effects of exposure to crude oil.
4.9.1
Introduction
Marine mammals, include whales, dolphins and porpoises (cetaceans) and seals (pinnipeds) and occupy the top level of the marine food chain. Although some species have a restricted distribution, most whales and dolphins have wide ranges, and there are no species that are endemic November 2010
to the UK. For many species there are marked seasonal and temporal changes in distribution and many species undergo regular seasonal migrations. There are two distinct categories of whales, baleen (mysticetes) and toothed (odontocetes). Baleen whales have baleen plates in their mouths rather than teeth, and use this to filter swarming krill and planktonic crustaceans from the seawater, whereas toothed whales feed mostly on fish and occasionally other small cetaceans. The Seabirds at Sea Team (SAST) has been recording seabird and cetaceans over the European continental shelf since 1979. From the SAST surveys a total of 15 species of cetaceans have been recorded. Fin (Balaenoptera physalus), sei (Balaenoptera Page 4.27
The Environment borealis) and humpback (Megaptera novaeangliae) whales were recorded in small numbers in the Faroe-Shetland Channel. The Atlantic white-sided dolphin (Lagenorhynchus acutus) was the most numerous cetacean recorded over all surveys and the long-finned pilot whale (Globicephala melas) second most abundant. The Sea Watch Foundation (formerly the UK Mammal Society Cetacean Group) has been collecting data on marine mammals from UK and Irish waters since 1973. The Sea Mammal Research Unit (SMRU) coordinated surveys through the North Sea in 1994 and 2005 (SCANS & SCANS II) and, since these remain the largest abundance estimates for cetaceans in European waters, are considered to provide the most reliable estimates of population size.
4.9.2
Cetaceans
SMRU have concluded from interpreting both the SCANS and SCANS II data that the most abundant cetacean found in the Quad204 Project area is the Atlantic white-sided dolphin with highest densities occurring in June, July and September (BP, 2004; Cross et al., 2006; De Boer et al., 2006). Other cetaceans occurring in moderate-high densities in the area include long-finned pilot whale, killer whale (Orcinus orca), sei whale, fin whale and sperm whale (Physeter macrocephalus). Low densities of harbour porpoise (Phocoena phocoena), minke whale (Balaenoptera acutorostrata), white-beaked dolphin (Lagenorhynchus
albirostris), Risso’s dolphin (Grampus griseus) and common dolphin (Delphinus delphis) have been recorded in areas immediately around the Quad204 Project area; with most sightings during the period between May and October, although some of these species have been observed in low densities during other months (SMRU, 2008). Information on the abundances and density of species that exist in and around the Quad204 Project area is given in * It should be noted that although the data is from the SCANS/SCANS II survey area, these encompass relatively large geographical areas and the field is located on the outer limits of these areas. Therefore estimates of the abundance should not be interpreted as estimates within localised areas around the Quad204 Project area. Figures in parentheses are coefficients of variation (CV). The abundance values given for the species have been calculated from controlled surveys rather than being absolute values. The method of analysis used to determine these values can be scrutinised by calculating a CV; this is a measure of the ability to repeatedly obtain the same value for a single analytical method and may also be called the precision. It is, in effect, a measure of how certain the estimates for abundance and density are (although not of how accurate they are since there is no feasible way to prove this).
Table 4.15. The data is not directly comparable between the two years as survey areas were different in 1994 and 2005.
Species
Survey
Year
Abundance*
Density
Density (other regions)
Harbour porpoise
SCANS
1994
37,144 (0.25)
0.363
0.010-0.812
SCANS II
2005
8,605 (1.11)
0.058 (1.11)
0.012-0.483
SCANS
1994
2,920 (0.40)
0.029
0.000-0.029
SCANS II
2005
1,888 (0.50)
0.013 (0.50)
0.009-0.023
SCANS
1994
1,157 (0.56)
0.011
0.000-0.022
SCANS II
2005
2,436 (0.62)
0.016 (0.62)
0.004-0.059
SCANS
1994
37,144 (0.25)
0.363
0.010-0.812
SCANS II
2005
1,510 (0.77)
0.010 (0.77)
0.010-0.180
Minke whale
White-beaked dolphin
Common dolphin
* It should be noted that although the data is from the SCANS/SCANS II survey area, these encompass relatively large geographical areas and the field is located on the outer limits of these areas. Therefore estimates of the abundance should not be interpreted as estimates within localised areas around the Quad204 Project area. Figures in parentheses are coefficients of variation (CV). The abundance values given for the species have been calculated from controlled surveys rather than being absolute values. The method of analysis used to determine these values can be scrutinised by calculating a CV; this is a measure of the ability to repeatedly obtain the same value for a single analytical method and may also be called the precision. It is, in effect, a measure of how certain the estimates for abundance and density are (although not of how accurate they are since there is no feasible way to prove this). Table 4.15: Cetacean abundances and densities recorded in the vicinity of the Quad204 Project area (SMRU, 2008)
Page 4.28
November 2010
The Environment Harbour porpoise and bottlenose dolphin (Tursiops truncates) are both listed in Annex II of the Habitats Directive (92/43EEC) (Section 4.12.3). All cetaceans are listed in Annex II of CITES, Appendix II of the Bern Convention, and Appendix IV of the EC Habitats Directive as species of European Community interest and in need of strict protection. They are also protected under Schedule 5 of the Wildlife and Countryside Act 1981. The seasonal occurrence of cetaceans around the Quad204 Project area is outlined in Table 4.16.
November 2010
Page 4.29
The Environment
Table 4.16: Seasonal occurrence of cetaceans in the Quad204 Project area (Pollock et al., 2000; Hammond et al., 2003; Reid et al., 2003; Stone, 2003a; 2003b; Macleod et al., 2003)
4.9.3
Pinnipeds
SMRU regularly monitors local seal populations using aerial survey techniques around the Scottish coastline. These surveys do extend to offshore regions where in particular grey seals have been equipped with Satellite Relay Data Loggers (SRDL) in order to study movements and foraging areas. The JNCC SAST has also been recording Page 4.30
seals during surveys in the Atlantic margin (Pollock et al., 2000). There are three species of seals which regularly occur to the west of Shetland of which only two of these are likely to be encountered in the vicinity of the Quad204 Project, namely the grey seal (Halichoerus grypus) and hooded seal (Cystophora cristata); both of which are protected under the EC Habitats and Species Directive. November 2010
The Environment The grey seal is a resident breeder mainly in the Western Isles, Orkney and Shetland. Grey seals tend to be present all year round in water depths of less than 200 m and have been recorded in all months by SAST, with lowest numbers between October and December when animals were ashore to pup and mate. Only low densities of grey seals have been observed in the area. Higher densities may be observed during periods of migration between their breeding sites in Faroe and Shetland (BP, 2004; McConnell et al., 1992, 1999). Hooded seals breed and moult on the packed ice of Arctic waters, but are also known to range extensively out with their breeding and moulting periods of March and July (Folkow et al., 1996). Hooded seals have only been recorded in deep waters over the Faroe-Shetland Channel with no records in water depths of less than 200 m (Pollock et al., 2000). Hooded seals may therefore be encountered in the vicinity.
4.10
Commercial fisheries
Environmental Sensitivity: Commercial fisheries are sensitive to natural changes in stocks and the loss of access to areas of the sea through the installation of new structures offshore and the establishment of exclusion zones. The potential also exists for demersal fishing gear to be snagged on obstructions on the seabed e.g. pipelines. In the event of an oil spill there may be economic impacts in terms of closure of fishing grounds and loss of confidence in the quality of fish being caught in the area.
4.10.1 Introduction Offshore structures have the potential to interfere with fishing activities as their physical presence may obstruct access to fishing grounds. Knowledge of fishing activities and the location of major fishing grounds is therefore a crucial consideration when considering the impacts of an offshore development. The Quad204 Project is located in ICES rectangles 49E5 and 49E6. Data on fishing effort for the Scottish fleet were sourced from the Scottish Government. In addition, BP commissioned two commercial fisheries studies (Brown & May, 2003 and SFF/Brown & May, 2010) which reviewed fishing levels in the area and wider West of Shetland waters. The waters around the Quad204 Project area support a mixed fishery of commercial importance, particularly for mackerel and herring. Several species have suffered a significant decline since 2004, including mackerel, herring, great November 2010
silver smelt and the Greenland halibut. This section provides an overview of the fishing activity in the area based on available data. Fish species are characterised by both deep water species at the upper limit of their range and species regarded as typical of the continental shelf at the lower limits of their range. The main commercial species exploited include mackerel, saithe and monkfish.
4.10.2 Fishing effort SFF/Brown & May (2010) obtained satellite tracking from the Marine Fisheries Agency (MFA) for UK over-15 m vessels that gives an indication of the numbers of vessels sighted within the Quad204 Project area. Figure 4.13 gives the average satellite density of UK over-15m vessels in the regional study area and Figure 4.14 gives the average satellite density in the local study areas. It is clear that there have been very few vessel sightings in the immediate vicinity of the Quad204 Project area. The lack of vessels in this area can be explained by the 500 m exclusion zone which surrounds the existing FPSO. It can be seen that the majority of activity in the West of Shetland is located along and around the 200 m depth contour. There is less activity in the Foinaven/Schiehallion local study area, largely as a result of seabed contours and associated water depth (SFF/Brown & May, 2010). It should be noted that it is not possible to state with full confidence that the vessels recorded in the area were fishing; it is possible that some will have only have been steaming through the area. Fishing activity occurs all year round (Figure 4.15). There is a general peak in the summer months for single and twin rig demersal trawlers, with additional long lining effort in the last quarter (SFF/Brown & May, 2010). Pelagic effort (mid water trawls) is recorded at considerably higher levels in January and February (SFF/Brown & May, 2010). Significant levels of foreign vessel activity occur in the West of Shetland area. In previous years it was possible to assess the level of foreign vessel activity through analysis of satellite tracking data, the MFA is not now permitted to release any satellite tracking data of foreign vessels. SFF/Brown & May (2010) report that it has been possible to obtain the fisheries over-flight surveillance sightings data from the MFA and that these data allow for assessment of the different nationalities active in the area, as well as establishing the fishing method undertaken by these vessels. Page 4.31
The Environment
Figure 4.14: Average satellite density of UK over-15 metre vessels in the local study areas, 2005-2008 (SFF/Brown & May, 2010)
Figure 4.13: Average satellite density of UK over-15 metre vessels in the regional study area, 20052008 (SFF/Brown & May, 2010)
Page 4.32
November 2010
The Environment
Fishing Effort (Days) (averaged 2004-2008)
350
ICES Rectangle 49E5 300 250 200 150 100 50 0
Jan
Feb
March
April
May
June
July
August
Sep
Oct
Nov
Dec
Otter trawls - bottom
72
96
158
178
322
271
212
141
114
116
64
38
Otter twin trawls
24
75
57
67
69
93
62
21
17
22
29
21
Longlines
1
1
1
4
2
0
0
10
16
37
60
53
Otter trawls - midwater
17
9
1
0
0
0
1
1
1
1
2
1
Otter trawls (not specified)
0
11
0
0
1
3
1
0
8
0
0
0
Pair trawls - midwater
11
4
0
0
0
0
0
2
0
1
2
1
Gillnets
0
0
0
2
5
1
3
0
0
0
0
0
Beam trawls
0
0
0
0
9
0
0
0
0
0
1
0
Pair trawls - bottom
0
3
0
2
0
0
0
0
0
0
3
0
Scottish seines
0
0
0
4
0
0
0
0
0
0
0
0
Figure 4.15: Averaged seasonal fishing effort by fishing method in ICES rectangle 49E5 (2004-2008) (SFF/Brown & May, 2010)
Figure 4.16 shows the fisheries surveillance sightings (over-flight) by nationality in the study area. As the number of sightings by nationality demonstrates, the five most active countries (in addition to the UK) are Spain, Norway, France, Germany and the Faroes.
Figure 4.16: Vessel distribution by nationality (surveillance sightings) within the Foinaven/Schiehallion local study area (SFF/Brown & May, 2010)
November 2010
The bottom otter trawl is by far the most commonly used gear in the Quad204 Project area (Table 4.17). The otter trawl comprises a large net bag that is drawn along or close to the seabed to catch demersal fish. Depending on the construction and rigging, the basic otter trawl can be used on a variety of seabed types and conditions for both finfish and shellfish species (FOOCG, 2001). Of the range of trawling fishing techniques used in the area, demersal otter trawls (heavy and light) are expected to exert the greatest impact on subsea structures. Otter trawls can weigh up to 1.5 tonnes and incorporate boards which allow the net to maintain a horizontal spread during trawling. On light demersal trawls the otter boards are usually of a much smaller and lighter construction and thus their impact on any seabed structures is greatly reduced.
Page 4.33
The Environment Gear type
Days fished using this gear type (%)
Otter trawls - bottom
62.3
Otter twin trawls
17.1
Set longlines
9.0
Set gillnets (anchored)
ICES Rectangle 49E5
ICES Rectangle 49E6
Species
Average weight landed 2007 - 2009
Species
Average weight landed 2007 - 2009
Mackerel
1522.6
Monks or Anglers
957.7
2.6
Saithe
1082.7
Hake
656.0
Gillnets (not specified)
2.4
Hake
385.5
Saithe
615.9
Longlines (not specified)
1.7
Herring
277.0
Mackerel
402.4
Pots
0.8
Haddock
155.2
Cod
342.4
Gillnets and entangling nets
0.8
Ling
143.9
Ling
201.2
Pair trawls - midwater
0.7
Halibut Greenland
76.0
Haddock
157.4
Pair trawls - bottom
0.7 Megrim
69.7
Megrim
86.3
Otter trawls (not specified)
0.6 Bream Ray's
73.7
0.5
Monks or Anglers
66.1
Otter trawls - midwater Scottish seines
0.3
Redfishes
48.6
Whiting
48.4
With purse lines (purse seines
0.2
Beam trawls
<0.1
Table 4.17: Most commonly used gear types in ICES rectangles 49E5 and 49E6 over the period 2006 – 2008 (Scottish Government, pers. comm.)
4.10.3 Fish landings SFF/Brown & May (2010) report that ICES Rectangle 49E5, within which the majority of the Foinaven/Schiehallion area is located, has the highest landings values in the regional study area. However, when quota becomes restricted within a designated area it is known for vessels to attribute landings to another sea area. As a result of the boundary of two ICES Areas (IVa and VIa) falling along the 4° line, and ICES Rectangle 49E5 falling immediately to the west and not within the more restricted North Sea area, this square has historically been known to have incurred substantial levels of misreporting, specifically overreporting (SFF/Brown & May, 2010). An analysis for fish landings data has been carried out for 2007 – 2009 for both ICES rectangles 49E5 and 49E6. During this time period an average of 7,729 tonnes of fish was landed annually. Mackerel, saithe and hake dominate the landings. Other species such as monkfish have significant landings (Table 4.18).
Page 4.34
Table 4.18: Top ten species by live weight (tonnes) landed by Scottish based vessels into Scotland in 2007, 2008 and 2009 for ICES rectangles 49E5 & 49E6 (Scottish Government pers. comm., 2010)
The annual demersal landings for all UK and foreign vessels landing in Scotland in 2009 were 7,194 tonnes from ICES rectangles 49E5 and 49E6. This tonnage is an increase on 2007 and 2008 landings of 6,288 and 2,901 tonnes respectively. The 2009 landings represent approximately 11% of the total demersal landings into Scotland by Scottish based vessels for ICES Division IVa (Scottish Government, pers. comm., 2010). The annual pelagic landings for all UK and foreign vessels landing in Scotland in 2009 were 3,018 tonnes from ICES rectangles 49E5 and 49E6. This tonnage is an increase on 2008 (2,094 tonnes) and on 2007 (1,554). The 2009 landings represent approximately 5% of the total pelagic landings into Scotland by Scottish based vessels for ICES Division IVa (Scottish Government pers. comm., 2010). The annual shellfish landings for all UK and foreign vessels landing in Scotland in 2009 were 18.9 tonnes from ICES rectangles 49E5 and 49E6. This tonnage represents a decrease on both 2007 figures (81.6 tonnes) and 2008 (39.5 tonnes) figures. The 2008 landings represent approximately 0.08% of the total shellfish landings in Scotland by Scottish based vessels for ICES November 2010
The Environment Division IVa.
4.11
(MEHRAs), areas that are most sensitive to shipping pollution incidents (Figure 4.17).
Other sea users
4.11.1 Shipping Anatec (2010) identified numerous shipping routes passing through the Quad204 area. Levels of shipping in the waters to the north of Scotland are relatively low when compared with other parts of the UK, e.g. the English Channel and North Sea. The most heavily used routes are the Pentland Firth, Fair Isle Channel and waters west of Shetland (Figure 4.17). Commercial traffic in the area is typically comprised of vessels en route to and from SVT and vessels in transit across the Atlantic (Table 4.19). The risk of a marine pollution event from shipping, especially shipping of petroleum products, has led to the designation of a number of Marine Environment High Risk Areas
Figure 4.17: Shipping routes passing the Quad204 Project area
November 2010
Page 4.35
The Environment Route no.
Route name
Closest point of approach (nm)
Bearing (°)
No. ships per annum
% of total
1
Aberdeen-Foinaven*
3.4
227
166
17%
2
Schiehallion Field-Sullom Voe*
3.8
86
130
13%
3
Moray Firth-Schiehallion (tanker)
3.8
87
20
2%
4
Aberdeen-Schiehallion*
3.8
87
102
10%
5
Moray Firth-Schiehallion (supply)*
3.8
93
182
18%
6
Sullom Voe-America North*
6.4
162
85
9%
7
Canada-Sullom Voe
8.1
343
20
2%
8
Humber-Faroes
8.5
47
5
1%
9
Faroes-Rotterdam*
9.0
236
50
5%
10
Kattegat-Iceland*
9.8
201
225
23%
985
100%
TOTAL
*Where two or more routes have identical closest point of approach (CPA) and bearing they have been grouped together. In this case, the description lists the sub-route with the most ships per year. Table 4.19: Shipping routes identified within 10 nm of the Quad204 Project (Anatec, 2010)
4.11.2 Wrecks The UK Hydrographic Office (UKHO) has compiled a detailed report on seabed features within 10 km of the replacement Quad204 FPSO (UKHO, unpublished data). A total of 3 such features were identified in the area, two of which are categorised as foul grounds and one as a non-dangerous wreck. The location of the features are detailed in Table 4.20 and shown in Figure 4.18. None of these wrecks are in the immediate vicinity of the Quad204 Project.
Seabed feature
Approximate depth (m)
Date sunk
Distance/direction from Quad204 Project
Details
Foul Ground Anchor
500 m
17/5/95
3.2 km NW
Lost during mooring recovery operation
Foul Ground - Drill Casing
490 m
14/10/94
9 km W
String of drill casing dropped onto seabed by the rig ‘Sovereign Explorer’
Wreck
405 m
25/07/17
2.9 km NW
Norwegian schooner captured and sunk by a German U-boat while on passage from Stavanger to Halifax.
Table 4.20: Seabed features identified within 10 km of the Quad204 Project (UKHO, unpublished data)
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The Environment
Figure 4.18: Seabed features identified within 10 km of the Quad204 Project (UKHO, unpublished data)
to Clair (Figure 4.19).
4.11.3 Military activities There are no charted military exercises areas or other specified sites in the area, although the area may be occasionally used by aircraft and surface or submarine craft during training and NATO exercises (DTI, 2003). Hydrophones to track submarines are present on the seabed in the Atlantic Margin area, although information on their location is confidential. The nearest practice and exercise area (PEXA) is located over 110 km to the south (Figure 4.19).
4.11.4 Submarine cables The closest known submarine telecommunication or power cable to the Quad204 Project is the SHEFA 2 (segment 5) which connects Schiehallion
November 2010
4.11.5 Existing oil and gas activity There is a long history of oil and gas activity north and west of Scotland, with the first well being drilled in 1972 and the first potentially commercial discovery (the Clair field) made in July 1977. To date, the Foinaven, Schiehallion/Loyal and Clair fields are the only producing fields in the region, with first oil in 1997, 1998 and 2005 respectively. In 2002, the West of Shetland Pipeline System (WOSPS) was installed to transport surplus gas from the Foinaven and Schiehallion fields to the Magnus field in the northern North Sea, via Sullom Voe Terminal (SVT), as part of the Magnus Enhanced Oil Recovery Project.
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The Environment
Figure 4.19: Military practice and exercise areas and cables in the region
The Clair field came on stream in early 2005; produced fluids from the field are transported to SVT through a 105 km pipeline constructed specifically for the Clair field with gas being exported through the WOSPS. Recently, the development of the Laggan and Tormore gas fields has been approved, where drilling operations are due to start in 2012. In addition, there are a number of other recent finds and on-going appraisals to the west of Shetland, including Chevron Rosebank which was drilled in Page 4.38
2007, the large gas find in the Glenlivet field, successfully drilled in 2009 and a recent gas discovery located in Block 204/13a and 14b known as Tornado at a depth of 1048 m.
4.11.6 Marine noise The principle sources of man made noise in the area are likely to be nearby shipping and oil and gas activity. The main sources of natural background noise in the region of the Quad204 Project include wind, waves, precipitation and November 2010
The Environment tectonic activity as well as noises produced by cetaceans (US National Research Council, 2003). For many marine species, sound is important for communication, locating potential mates, searching for prey, avoiding predators and hazards and for short- and long-range navigation (UKMMAS, 2010). Noise at inappropriate volume and frequency can mask biologically relevant signals; it can lead to a variety of behavioural reactions; hearing organs can be adversely affected, and at very high levels, sound can injure or even kill marine life. The impacts of noise are reviewed in Chapter 8.
4.12
Conservation interest
area of potential Annex 1 Reef habitat to the north and west of Shetland (Figure 4.20). No designated sites are present in the project area, although there are sites of conservation interest located in the North East Atlantic (Table 4.21). The most important reef forming coral is Lophelia pertusa, which is widely distributed throughout the Atlantic. Records show a number of small colonies of Lophelia on a wreck situated approximately 4 km southwest of East Foinaven (BP Amoco, 2000) and more recently small colonies have been discovered on two umbilicals at the Foinaven FPSO and two risers at the Schiehallion FPSO. The location of existing and possible designated sites in the project area are shown in Figure 4.20.
4.12.2 Offshore areas of search 4.12.1 Offshore conservation EC Directive 92/43EEC on the Conservation of Natural Habitats and of Wild Flora and Fauna (the ‘Habitats Directive’), and the EC Directive 2009/147/EC (codified 79/409/EEC) on the Conservation of Wild Birds (the ‘Birds Directive’), are the main instruments of the European Union for safeguarding biodiversity. The Habitats Directive includes a requirement to establish a European Network of important high quality conservation sites that will make a significant contribution to conserving the habitats and species listed in Annexes I and II of the Directive. Habitat types and species listed in Annexes I and II are those considered to be in most need of conservation at a European Level (JNCC, 2002). The Offshore Petroleum Activities (Conservation of Habitats) Regulations 2007 (as amended) transpose the EU Habitats Directive (94/43/EEC) in UK law. These regulations apply to UK waters beyond 12 nautical miles (22 km) and up to 200 nautical miles (370 km) offshore. Four habitats listed on Annex 1 to the Habitats Directive occur or potentially occur in the UK offshore area: h Sandbanks that are slightly covered by water all the time (<20 m) h Reefs h Submarine structures associated with gas seeps and pockmarks h Submerged or partially submerged sea caves As noted in Section 4.4, the Quad204 Project lies in an area dominated by iceberg ploughmarks; this seabed type has the potential to act as a Reef habitat. As a result, JNCC (Undated) report a large
November 2010
JNCC has, in recent years, been refining information on Annex I habitat distribution in UK offshore waters. The JNCC Data and Interpretation Group use the location of potential and known Annex I habitats to create ‘Areas of Search’ (AoS) for offshore SACs. The closest AoS to the Quad204 Project is located approximately 150 km to the south west (Figure 4.20). Once an AoS has been delineated, a literature search, or data-mining stage is conducted to collate all existing information for that area. For some AoS, the data mining phase may highlight sufficient data to assess the AoS against published SAC selection criteria. If insufficient data is available, then collaborative or commissioned survey is considered. All data collected on the survey are then analysed and interpreted, with particular attention given to determining the presence or absence of Annex I habitat, as well as the biological communities living on the seabed. New survey data compliments data already gathered through the data mining phase and is used to assess the AoS against the SAC selection criteria (JNCC, 2009d). The Quad204 Project lies in an extensive area of potential Reef habitat, which stretches north east and south west along the shelf break. In addition, JNCC (2010a) has, using the ESAS database, identified a number of important hotspots for seabirds in the West of Shetland area. These areas of search for marine SPAs are shown in Figure 4.20. It is important to note that whilst these may be areas of importance to some seabird species, these areas have not yet received any formal designation.
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The Environment Name
Designation
Site description
Darwin Mounds
cSAC/SCI
Sandy mounds on the seafloor are topped with thickets of the cold water coral Lophelia pertusa. This is a unique situation as the coral is growing on sand rather than attached to a hard surface. The thickets range in size from one to several metres in diameter and support many other species such as starfish and sponges (JNCC, 2008a).
160 km
North-west Rockall Bank
cSAC/SCI
Rockall Bank is an offshore bank in the North-East Atlantic. The north-west area of Rockall Bank is covered in a layer of fine sediment, gravel, cobbles and boulders of glacial origin. Some of these are shaped into characteristic 'ploughmark' formations, formed by the ploughing movement of icebergs through the seabed at the end of the last ice age. Animals present include the coral Caryophyllia sp., squat lobsters, brittlestars and the bluemouth red fish. In between areas of stony reef are large patches of cold water coral reef made up of Lophelia pertusa and Madrepora oculata, interspersed with other species such as erect sponges and pencil urchins. Rockall Bank is potentially one of the most extensive sites of cold water coral reef in UK waters. Harbour porpoise are present at North-West Rockall Bank and are included as a nonqualifying feature (JNCC, 2009b).
580 km
Wyville Thomson Ridge
cSAC/SCI
Wyville Thomson Ridge is a rock ridge at the northern end of Rockall Trough rising from over 1000 m at its deepest point to 400 m at the summit. Along the ridge there are large areas of stony reef, thought to have been formed by the ploughing movement of icebergs through the seabed at the end of the last ice age. Bedrock reef is present on the flanks of the ridge and, due to the differences in water masses, there are different species compositions on either side. These reef communities support sea urchins, sea spiders, sea cucumbers and a range of colourful sponges and soft corals. Bottlenose dolphins are present at Wyville Thomson Ridge and are included as a nonqualifying feature (JNCC, 2008b).
110 km
Hatton Bank
dSAC
Hatton Bank is a large volcanic bank in the North-East Atlantic. The depth of the bank ranges from less than 500 to over 1000 metres. The hard substrates provided by the stony and bedrock reef on the site support a wide array of species. These include scleractinian corals, lace corals, black corals, soft corals and cup corals as well as seafans and sponges. Cold water coral reefs, made up of Lophelia pertusa and Madrepora oculata, are also present (JNCC, 2009c).
590 km
Approximate distance from Quad204 Project
Table 4.21: Designated sites in UK waters to the west of Shetland
4.12.3 Important species A number of marine species in UK waters have been identified for protection under Annex II of the European Habitats Directive. Those that are found in UK offshore waters are the grey seal, harbour seal (Phoca vitulina), bottlenose dolphin and harbour porpoise. Of these, only the harbour porpoise is likely to be present in any numbers and with any regularity in the Quad204 Project area. This species is widely distributed in UKCS waters. Page 4.40
The deep water area to the west of Shetland is therefore not considered unique to these Annex II species. The European storm petrel has been nominated for inclusion in Annex I. The population of storm petrels to the west of Shetland is considered stable. Storm petrels are widely distributed over the whole shelf break west of Shetland between May and November (Taylor and Reid, 2000).
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The Environment
Figure 4.20: Offshore protected areas
4.12.4 Coastal conservation areas Coastal conservation areas and those areas which are highlighted as environmentally sensitive to potential oil spill are described in Chapter 10 Accidental Events.
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Page 4.42
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The EIA Process
5
The Environmental Impact Assessment Process
This chapter describes how the environmental issues associated with the Quad204 Project have been identified and addressed, and how BP has sought and taken account of the opinions of external stakeholders during this process.
5.1
Overview
Environmental Impact Assessment (EIA) is a process which identifies the environmental effects (both negative and positive) of development proposals and aims to prevent, reduce and offset any adverse impacts (Scottish Government, 1998). The Council Directive (85/337/EEC as amended by Directives 97/11/EC and 2003/35/EC) defines the requirements for an EIA. Central to a pro-active EIA of a development such as Quad204 is the requirement to identify issues 5 that could have an impact on the environment, other users of that environment, and potential cumulative and transboundary impacts. Once identified, these issues must be assessed to define the level of potential risk they present to the environment so that, where necessary, such risks can be removed or reduced through design or the adoption of operational measures (mitigation). As discussed in Section 1.4, the EIA process runs throughout the Quad204 Project and is integral to its design and subsequent operation. Figure 5.1 illustrates the linkages between the EIA process and the BP project phases.
process and outlines the key requirements for the third phase. Some of the key EIA elements are summarised below: h Scoping and consultation to establish any areas of concern regarding the Quad204 Project, involving meetings with environmental regulators and distribution of a scoping report to facilitate two way communication between BP and any interested parties h Commissioning supporting studies to inform the Quad204 Project EIA, adding to the body of knowledge accumulated during previous stages of the Schiehallion/Loyal field development. These include those shown in Table 5.1 h Identification of the key environmental issues associated with the project, using environmental issues identification (ENVID) and feedback from informal consultation h Identification of mitigation measures including design solutions and management control measures that will eliminate or limit significant environmental impacts h Detailed evaluation of each of the key issues and determination of the significance of the residual impacts h Assessment of cumulative and transboundary impacts The following sections outline the methodology used to identify and assess the potential impacts resulting from the Quad204 Project.
5.2
Environmental screening
h Environmental management through detailed design and subsequent project phases
Environmental screening, as per the BP environmental impact management process (EIMP-1, see Section 12.1), was first conducted for the Quad204 Project in 2006 during Appraise. Further environmental screening was conducted in 2008 during Select. In both cases, defined environmental sensitivity indicators were reviewed by a multi-disciplinary team and ranked by crossplotting environmental value against the project footprint using a Boston Square technique.
This ES covers the first two phases of the EIA
Key potential sensitivities identified included:
The EIA process falls into three broad phases: h Environmental screening during concept appraisal and selection h Detailed (core) environmental impact assessment during FEED
5
The term ‘issue’ has been used throughout the ES to refer to a source or activity that could result, or be perceived to result, in an impact on the environment. Use of this term includes stakeholder perceptions and concerns as well as more quantitative risk identification as applied during the Environmental Issues Identification (ENVID) process.
November 2010
h Oil spill risks to important conservation areas and cultural heritage designations on the coasts of Shetland and Orkney h Impact of noise on protected cetacean species h Seabed biodiversity h Interaction with the fishing industry
Page 5.1
The EIA Process
Figure 5.1: EIA process
conducted from mobile drilling rigs; installation and commissioning of the new Quad204 FPSO and new subsea infrastructure; all operational activities offshore; and decommissioning.
There were no environmental sensitivities identified that would suggest BP should not proceed with the project design. These issues have been assessed in Chapters 6 to 11.
5.3
Scoping and consultation
As discussed in Section 1.4, the EIA process assesses the full life of the project from installation to decommissioning. It covers the drilling to be
The environmental issues to be addressed during the EIA, the methods to be used and supporting studies required, were developed through a combination of consultation with interested parties (Section 5.3.1) and the use of defined environmental issues identification (ENVID)
Requirement for additional information
Supporting studies commissioned
Supporting studies for Front End Engineering Design (FEED)
Future legislation review to consider the implications of UK environmental legislation on the design of the Quad204 FPSO, and how this might change during the life of field Power generation BAT study Best Practicable Environmental Option (BPEO) study for the cleaning and disposal of produced sand (BP, 2009)
Additional information on environmental characteristics
Site and habitat survey coverage review for the Quad204 Project area Updated review of commercial fishery activity in the proposed development area (SFF and Brown & May Marine Ltd, 2010)
Data to support the assessment of impacts from potential discharges to sea
Environmental modelling of operational discharges for the Quad204 Project, including drilling discharges and aqueous discharges, using the DREAM model (BP, 2010a)
Assessment of potential noise impacts on marine mammals
Noise modelling of pile driving activity and operational noise for the Quad204 Project
Data to support the assessment of impacts from atmospheric emissions
Dispersion modelling of atmospheric emissions from the Quad204 FPSO (Xodus Aurora, 2010)
Data to support the assessment of risk from oil spill and the development of the oil spill response strategy
Oil spill modelling for the Quad204 Project using OSIS (OSR, 2010) Oil spill modelling for the Quad204 Project using OSCAR (BP, 2010b) Compilation of recent oil spill statistics for the UKCS (TINA Consultants Ltd, pers. comm.)
Table 5.1: Supporting studies commissioned as part of the Quad204 Project EIA
Page 5.2
November 2010
The EIA Process procedures (Section 5.4). The concerns identified during the scoping consultation process, together with the findings of the ENVIDs, provided a focus for the remainder of the EIA process (Section 5.5).
5.3.1
Consultation process
Following submission to DECC, an ES for a planned offshore development goes through a formal public consultation process. However, as part of the EIA process, prior to the submission of the ES, it is best practice to undertake informal consultation. Furthermore, BP internal management processes also require early consultation in order to integrate public and stakeholder concerns and opinions into the project decision-making process. Consequently, consultation with both statutory and non-statutory stakeholders was an integral component of the Quad204 Project EIA process. The primary aim of the informal consultation process was to facilitate two way communication about the proposed project with all relevant stakeholders. This allows any initial environmental concerns to be identified at an early stage and to be adequately addressed during the EIA process. For the Quad204 Project the issues raised during the informal consultation were used to finalise the detailed scope for the EIA and incorporated into the decision-making process at the design stage. Consultation is not related solely to the scoping phase of the project but is ongoing during the EIA process and after submission of the ES, as discussed in Section 5.3.5. A public consultation and disclosure plan was developed for the Quad204 Project which outlined how the project would undertake consultation to meet both statutory requirements and the intent of BP EIMP-3 (see Section 12.1). An initial informal consultation meeting was held between BP and DTI (now DECC) in June 2007. The objective of this meeting was to make DTI aware of BP’s plans with regard to the Quad204 Project, to investigate any future changes/additions to legislation which may effect the project, and to discuss the environmental consenting process for the project. A further informal consultation meeting was held in May 2008 with BERR (now DECC), the Joint Nature Conservation Committee (JNCC) and the Fisheries Research Services (now Marine Scotland Science, MSS) to provide an update on the project and seek guidance on the project elements to be included within the scope of the EIA. A follow up meeting was held in May 2010 with DECC, JNCC, Marine Scotland Science November 2010
(MSS) and the Scottish Fishermen’s Federation (SFF) to provide an update on the project and confirm the scope of the EIA. DECC, JNCC, MSS and SFF have also been updated with progress on the Quad204 Project at a series of regular meetings BP holds for that purpose. In order to consult more widely, BP identified 45 stakeholder organisations that were contacted by email and invited to provide comments to BP on the EIA Scoping Report (see Section 5.3.2). Stakeholders that did not reply to the initial mailing were followed up by telephone or email to ensure that any potential concerns were captured. All of the responses received are documented and appropriate actions identified through maintenance of a consultee database. A summary of the consultee issues raised and the BP response is provided in Section 5.3.4. Table 5.2 shows the organisations that were consulted during the Quad204 Project EIA process. For the formal consultation phase, the Quad204 Project ES is sent by BP to DECC, the JNCC, and to Marine Scotland. The public are made aware of the submission and details of the Quad204 Project through public notices in The Independent newspaper and local newspapers circulating in the vicinity of the coast nearest the development. The ES is available to download on the BP Scotland home page (Section 5.3.3).
5.3.2
Scoping report
BP prepared a Scoping Report for the EIA (BP, 2010c) to support the informal consultation process. The objective of the scoping document was to provide key stakeholders, including DECC and its statutory consultees, with an overview of the Quad204 Project and to facilitate their input. The Scoping Report included: h An overview of the proposed Quad204 Project and how alternative options will be addressed in the ES h An overview of the environment in the Quad204 Project area h The proposed scope of the EIA and an outline of the process to be followed together with the governing legislation and BP procedures h An outline of the key potential environmental issues and the supporting studies that will be required to inform the EIA The Scoping Report was uploaded to the BP Scotland homepage in August 2010 and an email sent to stakeholders drawing their attention to the Page 5.3
The EIA Process
Table 5.2: Organisations consulted during the Quad204 Project EIA process
document and inviting comment.
comment was in relation to accidental events.
5.3.3 Webpage
All environmental concerns raised by stakeholders specific to the Quad204 Project were taken forward into the EIA process and are summarised in Table 5.3 and Table 5.4. The issues raised contributed to finalising the detailed scope of the EIA.
The BP Scotland homepage (accessible from www.bp.com) will be used to allow the public and consultees to have access to the Scoping Report and Environmental Statement and other key documents as the project progresses.
5.3.4 Issues raised during consultation All of the responses received were documented and appropriate actions identified. The consultation process identified a range of issues which were either directly associated with the Quad204 Project or with more strategic issues. Each individual issue raised was considered and addressed by BP and, where appropriate, individual responses compiled and further meetings arranged. The most commonly raised Page 5.4
November 2010
The EIA Process Consultee organisation
Issues raised
BP response
ES chapter
DECC (formerly DTI)
1. Requirement for an ES – requested that an ES is undertaken as increase in production levels would be a trigger for a statutory ES.
1. Production levels will increase and therefore a requirement for an ES is recognised.
3 - The Development
2. Brownfield site – recognised that the Quad204 Project is making use of a brownfield site, however, stakeholder involvement could be an issue.
2. Stakeholder consultation has been undertaken throughout the EIA process.
3. Produced water – philosophy of zero discharge of harmful materials; future focus may be given to other parameters of produced water such as heavy metal concentration and, radiation. As there are no effective treatment processes for these parameters PWRI will be the focus.
3. PWRI system will be installed on the new FPSO.
4. Chemical use – not seen to be an issue as long as the project plans to carry on the current BP philosophy of minimising chemical usage and replacing chemicals which contain a substitution warning.
5. Seismic survey has been included as part of the EIA. Further information will be provided as part of PON14 application process.
5. Seismic surveys - enquired whether seismic surveys would be included in the ES.
6. Existing moorings will be removed and replaced with new mooring lines.
6. FPSO moorings - requested clarification on whether the FPSO moorings would be replaced and the new mooring envelope. 7. Risers – enquired about the design life of the risers. 8. Claw field - enquired what was happening about the Claw field.
Scottish Fishermen’s Federation (SFF)
1. Oil export pipeline – enquired if Schiehallion will be there for a while and if tanker offloading would still be required and the amount of shuttling likely to take place. 2. Pipelines – enquired whether some pipelines would be made redundant. 3. Seismic surveys – enquired if there was any programme for seismic surveying.
4. Chemicals will only be used in accordance with the PON15 permit conditions and according to BP’s internal requirements.
5 - The EIA Process 6 - Physical Presence 7 - Discharges to Sea 8 - Underwater Noise
7. Original design life of the risers was 20 years. Risers on the current FPSO that will not last beyond the design life will be replaced. 8. Some of the new Quad204 wells will target the Claw area however, there are no plans for a Claw drill centre or tie-back. 1. Confirmed that shuttle tanker transport was the most likely scenario and would remain the same as is currently taking place.
3 – The Development
2. Redundant equipment will be removed where safe and practical to do so. 3. Confirmed that a PON14 was submitted for a 2010 survey and that future surveys would be captured within the scope of the EIA.
Joint Nature Conservation Committee (JNCC)
1. Seabed surveys - enquired whether existing information on seabed surveys undertaken West of Shetland would be included in the ES. MSS also enquired when the last seabed survey was undertaken for the Schiehallion area. 2. Discharges to sea – enquired about the purging of the risers and discharges to the environment. 3. Subsea control system - enquired why an open loop system was used.
Marine Scotland Science (MSS)
1. Information provided. 2. There will be no discharges as any fluids from the risers will be returned to the FPSO.
4 – The Environment
3. This is standard practice and the way that the system was originally designed.
1. Drilling – question concerning the plan for drilling further wells.
1. Drilling is planned to start 1 year before the new FPSO arrives.
3 – The Development
2. Guard vessel – enquired whether there would be a guard vessel permanently in the area once the existing FPSO is taken away – recommended that one is used.
2. A guard vessel will be present.
6 - Physical Presence
3. Enquired whether the disconnected flowlines and risers would be anchored or held down under their own weight. ‘Loops’ arising from the risers when they are left on the seabed could be a potential interaction with fishing gear.
3. The disconnected flowlines and risers would be held down under their own weight.
7 - Discharges to Sea
4. Amount is relatively small.
4. Sand – enquired about the volumes of sand discharged from Schiehallion.
Table 5.3: Issues raised during meetings with DECC and statutory consultees
November 2010
Page 5.5
The EIA Process Consultee organisation
Issues raised
BP response
ES chapter
Association of Shetland Community Councils
No comments to make.
None required
N/A
Atlantic Frontier Environmental Forum
No comments to make.
None required
N/A
Department of Energy and Climate Change (DECC)
1. The scope of the section dealing with accidental events should be reviewed in the light of new guidance that is currently being prepared by the department’s Offshore Environmental Inspectorate. When drafting an OPEP for a development and associated wells, applicants will be expected to consider total loss of well control that can only be rectified by drilling a relief well, and expected to link that document to the detailed environmental impact assessment (including shoreline protection at potential beaching sites) detailed in the Environmental Statement (ES). Ideally this section of the ES should be annexed to the ES, so that it can be separately maintained and updated in the light of any new information. Where the development does not have a current ES, applicants will be required to prepare a stand-alone impact assessment to support the OPEP, and may be required to submit that document to the Department for review.
1. Comments addressed within the ES
10 - Accidental Events
2. Comments addressed within the ES
Appendix E – Commitments Register
2. The scope of the ES should also include a section summarising any environmental commitments detailed in the body of the ES, which again should be annexed to the main report. This annex will be used to assess progress against the commitments during offshore inspections and at environmental review meetings. Environmental Concern Orkney
No comments to make.
None required
N/A
Faroese Environment Agency
No comments to make.
None required
N/A
Friends of the Earth Scotland
No comments to make.
None required
N/A
Historic Scotland
Note that impacts on cultural heritage are not considered in the scoping report. However, Historic Scotland can confirm that they are content for historic environmental features within their statutory remit to be screened out.
None required
N/A
Joint Nature Conservation Committee (JNCC)
We are pleased that we have been involved in meetings regarding this development throughout its progress to date and feel that the scoping report was robust and outlined the main environmental considerations we would want to see addressed within the forthcoming ES.
Comments addressed within the ES
3 – The Development
The ES should ensure it is very clear in outlining which existing structures will be used within the development and where new structures may be required. This, alongside a thorough presentation of environmental data for this developed area will enable a detailed understanding of the footprint of this development to be understood, alongside any other inputs to the marine environment (e.g. potential impacts from drill cuttings, rock dumping, mattressing etc using realistic worst case scenarios).
Page 5.6
4 – The Environment 6 - Physical Presence 8 –Underwater Noise
November 2010
The EIA Process Consultee organisation
Issues raised
BP response
ES chapter
Ensuring that all potential noise sources are addressed within the ES will enable a full assessment of any potential impact to European Protected Species (EPS) to be undertaken. If any noise sources are thought to reach sound levels that could cause injury and/or disturbance to a EPS then we would expect to see a Stage I EPS risk assessment contained within the ES. Also, BP should take into consideration that work has now begun on identifying Scottish Marine Protected Areas via The Marine (Scotland) Act and UK Marine and Coastal Access Act. As this development will significantly extend the life of the Schiehallion and Loyal fields, BP should keep themselves up to date with the latest developments of this work programme and consider its relevance to all future proposals within Scottish waters. Lerwick Port Authority
Fully supports the development of fields West of Shetland, including Quad 204
None required
N/A
Local Authorities International Environmental Organisation
1. All installations and structures should be removed at the end of field life
1. Installations and structures will be removed in line with the approved decommissioning plan at the time
2 - Alternatives
2. Oil spill plans should consider a worst possible spill from transfer operations between FPSO and (shuttle) tanker 3. Transfer operations described above should only be conducted when there is a response vessel within reasonable proximity of the field 4. Vessels should use the lightest available fuel oil to reduce atmospheric emissions
2. Oil spills are addressed in Accidental Events chapter 3. The FPSO will have a standby vessel
6. Mitigation measures should be implemented to reduce the effects of marine noise on the marine ecosystem
4. BP will use low sulphur diesel containing a maximum of 0.1 wt% sulphur
7. Decisions made based on current baseline data should be reviewed regularly as improvements to scientific knowledge are made
5. The FPSO hull will be double sided and double bottomed
8. All current regulations on produced water, cuttings piles and chemical discharges should be exceeded. BP should employ regular frequent reviews to ensure Best Available Techniques (BAT) and Best Environmental Practices (BEP) are used.
6. Mitigation for marine noise will be in place
5. The FPSO hull should be double skinned
3 – The Development 8 – Underwater Noise 9 – Atmospheric Emissions 12 – Environmental Management
7.BP’s management systems will ensure that where appropriate decisions are reviewed as new data become available 8. BP has presented targets in the ES where appropriate where regulations are exceeded. These targets will be reviewed in line with BP management systems and operational permits (which require periodic BAT reviews). BAT and BEP have been used on the project
Marine Scotland
No extensive comments to raise. The scoping report adequately covers areas of interest to Marine Scotland.
Comments addressed within the ES
Chapter 3 – The Development
Area deserving more attention is decommissioning. Would expect a suggested timetable for the decommissioning of the different phases as far as can presently be predicted. Maritime and Coastguard Agency (MCA)
No objection at this stage on Safety of Navigation, subject to standard conditions being met.
None required
N/A
Ministry of Defence (MOD)
No comments to make.
None required
N/A
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Page 5.7
The EIA Process Consultee organisation
Issues raised
BP response
ES chapter
National Register of Historic Wrecks
No comments to make.
None required
N/A
Nautical Archaeological Society
No comments to make.
None required
N/A
Northern Lighthouse Board (NLB)
Notice(s) to Mariners, Radio Navigation Warning and publication in appropriate bulletins detailing the scheduling of the works should be promulgated in advance of commencement of operations.
Requirements are noted
N/A
All sub surface structure and pipelines should be notified to the UK Hydrographic Office and ‘Kingfisher Bulletin’ for appropriate chart and publication revision including information on the nature and timescale of any works carried out in the marine environment relating to the project. Deployment of the MODU and FPSO will require lighting and marking as per the Standard Marking Schedule for Offshore Installations (Rev 11/94). We would anticipate a Navigational Risk Assessment to be included within any application to establish the development. NLB require notification of any rig moves. Orkney Fisheries Association
No comments to make.
None required
N/A
Orkney Islands Council
No comments to make.
None required
N/A
Royal Society for the Protection of Birds (RSPB)
Main concern is to minimise the number of accidental oil spills which could impact seabirds both in the vicinity of the development and in Shetland and other island groups. The RPSB suggest that:
1. There is a limited weather window for offshore construction work West of Shetland which is during this period. Seabird vulnerability has been considered and mitigation measures are proposed.
10 – Accidental Events
1. Those operations from which accidental spills are most likely to occur should avoid the most sensitive periods for seabirds (February – September inclusive). 2. There should be adequate supplies of anti-oil pollution equipment, including dispersants, held infield on a support vessel. 3. Measures should be in place to minimise spillages of diesel oil during transfer operations.
2. Requirements are noted. The OPEP is being reviewed and RSPB’s concerns will be considered during this process. 3. Requirements are noted. Operational practices and procedures will be reviewed and RSPB’s concerns will be considered during this process.
Royal Yachting Association (RYA)
The RYA have no specific comments to make.
None required
N/A
Scottish Environment Protection Agency (SEPA)
Generally satisfied with the proposed scope of the EIA. Key issues that should be addressed in the EIA process include pollution prevention and waste management.
Comments addressed within the ES
11 - Waste
Scottish Government
No comments to make.
None required
N/A
Scottish Natural Heritage (SNH)
Welcome consideration of potential connectivity between coastal SPAs and seabirds using the offshore area.
Requirements are noted.
10 – Accidental Events
Providing the issue of marking and lighting is considered with navigational safety in mind the RYA has no objections.
Would like the opportunity to comment on the oil spill pollution plan when drafted.
Page 5.8
November 2010
The EIA Process Consultee organisation
Issues raised
BP response
ES chapter
Sea Mammal Research Unit
No comments to make.
None required
N/A
Shetland Amenity Trust
The EIA should include more details on the 13 wrecks which will be affected and the likely impact of development on them as well as a mitigation strategy as to how to mitigate for any impact.
BP has carried out research that suggests there are 3 wrecks within a 10km radius of the development. Effects on these wrecks are assessed within the ES.
4 – The Environment
The report should include plans showing the development and location of wrecks, including information on functions and all known information about the current state of the wreck.
6 – Physical Presence
Shetland Aquaculture
No comments to make.
None required
N/A
Shetland Oil Terminal Environmental Advisory Group
No comments to make.
None required
N/A
Shetland Biological Records Centre
No comments to make.
None required
N/A
Shetland Islands Council
No comments to make.
None required
N/A
Shetland Tourism Board/ Shetland Islands Tourism
No comments to make.
None required
N/A
UK Parliament
No comments to make.
None required
N/A
Whale and Dolphin Conservation Society
No specific comments.
Comments addressed within the ES
4 – The Environment
WWF
No comments to make.
None required
N/A
There is some information that demonstrates that this area off Shetland is important for a number of cetaceans, although more detailed baseline data are required both on species and on potential impacts.
Table 5.4: Issues raised during informal consultation and how they have been addressed
5.3.5
Consultation beyond the ES
All issues raised during the informal consultation process will be worked through as the project moves through detailed design, construction, installation and operation. Consultation will continue beyond the submission of the ES and consultees will continue to be able to input to the evolving project by email and meetings. The Quad204 Project is therefore committed to a continued dialogue with stakeholders and the BP Scotland homepage will be maintained as the project progresses to ensure the public is kept informed.
5.4
Environmental issues identification (ENVID)
ENVID workshops were undertaken for the Quad204 Project in relation to wells and reservoir; SURF (subsea umbilicals risers and flowlines); production November 2010
and export; and FPSO and utilities. The key objective of the workshops was to identify potential environmental issues resulting from the proposed project and agree practicable measures to ensure minimum harm to the environment throughout the operations. Environmental issues associated with the Quad204 Project were reviewed and ranked against a series of significance criteria. The methodology used is described in Section 5.5.
5.5
EIA methodology
Central to pro-active environmental impact assessment is the requirement to identify issues or aspects that could cause harm to the environment or other users of that environment. Once identified these issues are assessed to define the level i.e. the significance of potential impact that they present to the environment so that measures can be taken to Page 5.9
The EIA Process remove or reduce such impacts through design or operational measures (mitigation).
Overall significance definitions are provided in Table 5.7.
The significance of any potential impact is determined through the use of a risk assessment approach which employs the standard risk assessment philosophy of: Likelihood of occurrence (frequency/probability) x magnitude of impact (consequence) = Risk
Routine (Planned ) Operation (Frequency)
5
Continuous emission or permanent change over more than 5 years
The significance of potential risk is assessed against three drivers: h Regulatory compliance (R) - considering current and anticipated future legislative requirements and also corporate policies
4
h Environmental impact (E) - considering environmental sensitivities and scientifically established measures of risk, but also perceived risk or concern (precautionary principle)
3
The overall significance of any potential risk was then determined from the risk matrix (Table 5.8). Page 5.10
Likely -1
10 - >1 per year Event likely to occur more than once on the facility
Continuous emission or permanent change over less than 5 years
10 - 10 per year
OR
Could occur within the lifetime of the facility
Regular over less than 3 years OR Intermittent over more than 3 years
Possible -2
-1
Unlikely -3
-2
10 - 10 per year Event could occur within lifetime of 10 similar facilities Has occurred at similar facilities
Defining what constitutes unacceptable harm to the natural environment ultimately depends on what value society places on ecosystem integrity and biodiversity. In addressing the environmental impact driver (E, above), broad scientific criteria have been applied; whereas in rating the factors represented under stakeholder concern (S, above), wider concerns have been considered.
For every issue or aspect identified for the project, the potential risk was evaluated by combining the likelihood of occurrence (frequency/probability) (rated 1 to 5 as defined in Table 5.5) with the magnitude of the consequences for each of the three drivers indicated above - the highest consequence rating score in any of the driver categories was used (rated positive to severe as defined in Table 5.6). Both components are at best semi-quantitative, representing best judgements on the basis of available knowledge and experience, but provide a consistent and documented approach across the whole project.
Accidental Event 7 (Unplanned ) (Probability)
Regular over more than 3 years
h Stakeholder concern (S) - considering other sea users (potential conflict/concern resolution), interest groups and general public (perceptions and concerns)
It should be noted that BP considers all issues governed by environmental legislation (legislative control) to be significant. These are managed as part of routine business operations. However, for the purposes of the EIA, regulatory compliance rather than legislative control has been used to determine significance. The focus of the EIA is to identify activities that could have a significant environmental impact and to determine how these are mitigated.
6
Likelihood
2
One off event over lifetime of development over several weeks duration OR Once per year for <24 hours
1
0
One off event over lifetime of development for < 5 days
Will not occur
Remote -5
-3
10 - 10 per year Similar event has occurred somewhere in industry or similar industry but not likely to occur with current practices and procedures Extremely remote -5
< 10 per year Has never occurred within industry or similar industry but theoretically possible Will not occur
Table 5.5: Likelihood of occurrence (frequency/probability)
6
Planned environmental aspects are those that are guaranteed to occur over the course of operations and include single, intermittent and continuous events 7
Unplanned environmental aspects are those arising from abnormal activities or from hazardous or emergency situations
November 2010
The EIA Process
Table 5.6: Magnitude of consequences
November 2010
Page 5.11
The EIA Process
Table 5.8: Risk matrix
been applied issues are reassessed to see if overall impact significance has been reduced. The process used throughout a project, to help identify issues or aspects that could cause harm to the environment or other users of that environment, is referred to as environmental issues identification (ENVID). The outcomes for each of the potential issues identified are presented in the EIA matrices (Appendix D).
Table 5.7: Overall significance definitions
Once overall impact significance has been assessed appropriate mitigation measures should be applied to each area of impact with the aim of reducing the level of significance. Once mitigation measures have Page 5.12
Those issues given a final environmental ranking of minor or negligible were considered insignificant and were therefore not considered further in the EIA (i.e. screened out). Key issues identified for detailed impact assessment were brought forward based on potential effects from the proposed development. Aspects of the Quad204 Project activities identified as having potentially significant impacts before and after the application of mitigation measures are shown in Table 5.9, Table 5.10 and Table 5.11, and are reported within the following sections of this ES:
November 2010
The EIA Process h Physical presence (Chapter 6)
Quad204 Project and operation of the new FPSO.
h Discharges to sea (Chapter 7) h Underwater noise (Chapter 8) h Atmospheric emissions (Chapter 9) h Accidental events (Chapter 10) h Waste (Chapter 11)
5.6
Assessment of residual impacts
The ENVID process and the concerns raised during the informal consultation process together identified the key issues associated with the proposed project at the early design stage. These issues have been the driving environmental considerations throughout the EIA process, and mitigation measures have been incorporated into the project design in order to reduce or eliminate the significant potential environmental impacts. Later sections of the ES (Chapters 6 to 11) contain the findings of more detailed assessment of each issue and how it will be managed. In each chapter, the residual impacts are described and quantified, using predictive modelling methods as required. The potential cumulative and transboundary environmental impacts from the Quad204 Project are also considered within these chapters.
5.7
EIA integration with overall environmental management
To ensure that the design and operational procedures intended to minimise the environmental impact from the proposed project prove successful, the measures identified in Chapters 6 to 11 have been captured in a Commitments Register (Appendix E) and will be tracked throughout the
November 2010
Page 5.13
The EIA Process
Table 5.9: Aspects of the Quad204 Project wells, reservoir and SURF activities identified as having potentially significant impact (see Appendix D for full EIA matrix)
Page 5.14
November 2010
The EIA Process
Table 5.10: Aspects of the Quad204 Project production and export activities identified as having potentially significant impact (see Appendix D for full EIA matrix)
November 2010
Page 5.15
The EIA Process
Table 5.11: Aspects of the Quad204 Project FPSO and utilities activities identified as having potentially significant impact (see Appendix D for full EIA matrix)
Page 5.16
November 2010
Physical Presence
6
Physical Presence
This chapter discusses the potential environmental impacts associated with the physical presence of the FPSO, SURF infrastructure, and associated rigs and vessels in the offshore environment during the lifetime of the Quad204 Project. The potential impacts are divided into those that may impact the seabed and those that may impact on other sea users.
6.1
Seabed impacts
6.1.1
Introduction
Activities being conducted during the Quad204 Project which have the potential to impact the seabed include drilling and anchoring of the drilling rig; installation of SURF infrastructure and replacement of the FPSO (Table 6.1). Impacts from these activities may result in the direct physical injury of benthic species, the localised loss of seabed habitat or the resuspension of sediments. OSPAR (2009) report that, in recent years, there has been an improvement in the technology used to place infrastructure on the seabed and that there is greater awareness of the potential environmental impacts that these activities may cause. The Commission also stated that an assessment of the direct physical impact of placing a structure on the seabed should be included within an environmental statement for a development (OSPAR, 2009). Therefore the impacts identified for the Quad204 Project are discussed here, along with relevant mitigation measures.
(DepCon) application for permission to deposit pipeline protection materials should this be required. h The Offshore Petroleum Production and Pipelines (Assessment of Environmental Effects) Regulations 1999 (as amended) regulate the deposit of stabilisation or protection materials on the seabed. DepCon is a term normally reserved for the deposits made in relation to a pipeline and an application for such is made with the PWA application, and a specific DepCon authorisation granted by DECC. All other oil and gas related deposits are made to DECC under the appropriate PON15 eg B for drilling. h The Coast Protection Act 1949 regulates the locating of drilling rigs. BP will apply for a consent to locate the drilling rig in line with DECC ON14 guidance.
6.1.3
Potential impacts
Introduction A number of seabed surveys have been carried out in the vicinity of the Quad204 Project; such that it is possible to describe the benthic environment present in the area and therefore estimate the degree of potential impact from the activities described in Table 6.1. Survey data for the Quad204 Project area are presented in Chapter 4 (Section 4.4) and it should be noted that no potential Annex 1 habitats were recorded in the area. As described in Chapter 3: h There are no new drill centres planned as part of the project and drilling will occur at existing drill centre locations (Section 3.2.2)
It should be noted that the Quad204 Project is a redevelopment of the existing Schiehallion/Loyal field development, therefore much of the seabed likely to be affected by project activities will have experienced similar impacts during previous field development phases.
h The project will involve the continued use of the existing subsea, umbilical, riser flowline (SURF) infrastructure including the removal, reinstallation or replacement of some existing facilities and the addition of new SURF infrastructure (Table 3.6 in Section 3.4.1)
6.1.2 Regulatory control
h All new SURF infrastructure (with the exception of the new mooring line anchors and minor cross-overs) will be placed within existing corridors and drill centre locations (Figure 3.7 in Section 3.4.1)
The key regulatory drivers that relate to the activities described in this section and which will assist in reducing the possible impact on the seabed are described in Appendix A and summarised here as follows: h The Petroleum Act 1998 regulates the placement of pipelines and other permanent infrastructure onto the seabed. BP will apply for a Pipeline Works Authorisation (PWA) for the flowline and other subsea equipment installation operations. The PWA will include a deposit consent November 2010
h The new Quad204 FPSO will replace the existing Schiehallion FPSO at the same location with a slightly larger mooring envelope (Section 3.6.2)
Page 6.1
Physical Presence Activity
Drilling
Potential for seabed impact
Drilling of 25 new wells at the existing Schiehallion and Loyal drill centres
Direct physical injury of benthic species
Drilling rig:
Direct physical injury of benthic species
32 rig moves (see Note 1 below) 8 anchors with 1-2 km anchor spread
Temporary localised loss of seabed habitat
256 anchor deployments in total
Resuspension of sediments
Resuspension of sediments
Estimated that approx. 1200 m of chain will lie on the seabed Installation of subsea, umbilicals, risers and flowlines (SURF) infrastructure
25 new wellheads and subsea trees with protection structures at the existing Schiehallion and Loyal drill centres
Direct physical injury of benthic species Localised loss of seabed habitat/ introduction of hard substrata Resuspension of sediments
2 new manifolds with protection structures (one each at the Schiehallion West and Loyal drill centres)
Direct physical injury of benthic species Localised loss of seabed habitat/ introduction of hard substrata Resuspension of sediments.
Concrete mattresses where required
Direct physical injury of benthic species Localised loss of seabed habitat/ introduction of hard substrata Resuspension of sediments
5 new flowlines laid directly on the seabed within existing route corridors
Direct physical injury of benthic species
2 new static umbilicals
Temporary localised loss of seabed habitat/ introduction of hard substrata
3 existing dynamic umbilicals removed
Resuspension of sediments
1 new dynamic umbilical installed 1 existing dynamic umbilical repaired, retested and reinstalled 5 new flexible flowline jumpers between wellheads and manifolds and between manifolds and flowlines
Direct physical injury of benthic species Localised loss of seabed habitat/ introduction of hard substrata Resuspension of sediments
6 new risers to FPSO (6 new piles and 6 new suction anchors) and tie-in of new and existing flowlines
Direct physical injury of benthic species Localised loss of seabed habitat/ introduction of hard substrata Resuspension of sediments
FPSO replacement
Removal of 14 mooring lines currently installed and installation of 20 new mooring lines and suction anchors approximately 100 m further out from existing anchors which will remain in-situ
Direct physical injury of benthic species Localised loss of seabed habitat/ introduction of hard substrata Resuspension of sediments
Note 1: The number of rig moves exceeds the number of wells being drilled as a number of workovers are included in the drilling rig schedule Table 6.1: Summary of Quad204 Project activities with the potential for seabed impact
Page 6.2
November 2010
Physical Presence Drilling An additional 25 wells will be drilled at the Schiehallion and Loyal drill centres from a mobile semi-submersible drilling rig(s). Anchors are required to hold the rig in position during the course of its deployment. It is expected that anchors will be placed in one position on the seabed during the time that the drilling rig is operating. The anchors are placed on the seabed by anchor handler vessels and the anchor cable is winched in to allow the anchor to embed in the sediment. Drilling of the wells together with placement of the drilling rig anchors on the seabed and movement of anchor chain across the seabed, may result in the direct physical injury or death of benthic organisms that are present in the immediate area in which drilling will occur. The seabed is inhabited by numerous organisms (Section 4.4) including sessile organisms and animals that are unable to move rapidly. As such, some species, both infaunal and epifaunal, will be unable to move out of the area affected by drilling activity and thus may experience some degree of physical disturbance. This will be more problematic for sessile organisms as those that can move may be able to vacate the area. In addition, infaunal species may be able to move through the sediment and emerge outwith the affected area. Despite this, it is likely that some individual organisms will be lost from the environment. When anchors are removed from the seabed there is potential for mounds to form and to be left on the seabed; these commonly form where there is clay present within the seabed sediment. Although the surface sediments in the Quad204 region are composed of a thin veneer of sand, the underlying sediments are very soft to firm (occasionally stiff) sandy clays and silty clays, with gravel and occasional pebbles (Section 4.4.1). It is therefore considered that anchors associated with Quad204 drilling operations could lead to the formation of anchor mounds. In addition, interference with the seabed also has the potential to cause resuspension of seabed sediments, which can exert negative effects on habitat/species outwith the immediate area of activity. The likelihood of sediments becoming resuspended and the speed at which they will settle out of the water column will depend on the nature of the seabed sediments found in the area being developed and on the prevailing sediment transport system in the area. Larger particles will settle out of the water column more quickly than smaller particles (Farrell, 2005); therefore, sediment resuspension is likely to persist for a longer period in areas with a high percentage of fine sediments compared to November 2010
areas with a coarser sediment composition (Hitchcock et al., 1996, in Gubbay, 2003). The resuspension of sediments can result in the smothering of epifaunal benthic species (see Gubbay, 2003, for a review). Whilst some species may be exposed to settlement of only a small layer of sediments and be unaffected, others may experience thicker smothering or be unable to tolerate any covering at all. Infaunal species that are found within the sediment may be less susceptible to negative impacts of smothering. Conversely, resuspension of fine particulate matter may clog the delicate filtering apparatus of suspension feeders, which can result in their removal from silty sediments. It is possible that any existing drill cuttings piles may be disturbed, but since the chemicals used during previous drilling programmes are environmentally benign the impacts are not expected to extend past the resuspension of sediments described above. Potential impacts arising from the discharge to sea of drill cuttings, muds and cement are considered separately in Chapter 7. Installation of SURF infrastructure A number of additional subsea trees and manifolds will be required for the Quad204 Project. Concrete mattresses may also be required at certain locations along the flowline routes to protect existing infrastructure at flowline crossings (note: flowline crossings are not anticipated). It is not possible at this point to estimate with certainty the area of seabed that will be covered by concrete mattresses since the requirement has not yet been ascertained. The area of natural seabed potentially covered by these structures will be excluded from use by benthic species. The structures will comprise hard substrata upon which colonisation could occur. In addition, placement of the structures on the seabed may cause direct physical injury of benthic species and there may also be some resuspension of sediments. These impacts are described in the drilling section above and are not repeated here. Six additional flexible risers will be installed at the replacement FPSO requiring 6 new piles and 6 new suction anchors. Placement of the new piles and suction anchors could result in some long-term habitat loss (for the life of the development) as the original substrate under these items will no longer be available to benthic species. There may also be some direct physical injury of benthic species and resuspension of sediments (see the drilling section above for a summary of these impacts). Five new production flowlines will be installed, along with two new static umbilicals. The flowlines and umbilicals will be laid directly on the seabed with no Page 6.3
Physical Presence trenching or burial. A specialist dynamically positioned (DP) pipelay vessel will carry out flowline and umbilical installation. A clump weight anchor is placed at either the drill centre or the FPSO, and the flowline or umbilical is then lowered and connected to the clump weight that acts as an end restraint allowing the lay vessel to pay out the pipe as it moves along the route. Once laid the route is visually inspected by ROV to confirm its location and identify any large spans. Span rectification, if required, is then carried out using grout filled bags or suitable mattresses and supports. The as-laid data are fed back to the onshore team for records and charts to be updated. Experience at Schiehallion indicates that span formation (and therefore rectification) is not common due to the relatively consistent seabed and detailed pipeline route selection procedures. There is potential for loss of seabed habitat along the flowline and umbilical routes as the original substrate on which the lines are placed will no longer be available to benthic species. The installation operations may also disturb the surface layers of the seabed and also increase the turbidity and to a smaller extent increase mixing of the water column. These disturbances and their effects will be highly localised and extremely short-term. Other effects, such as direct physical injury of benthic species, may occur as a result (see the drilling section above for a summary of these impacts).
the project area have not identified any sensitive habitats or species or those of particular conservation concern. However, a number of mitigation measures will be applied to the project to limit, where possible, the negative impact on the benthic habitats and species of the area: h A detailed anchoring pattern will be developed prior to drilling operations to optimise the number of anchor placements required h If concrete mattresses are required, their location will be optimised during design to minimise footprint h All new SURF infrastructure (with the exception of the new mooring line anchors and minor crossovers) will be placed within existing corridors and drill centre locations therefore additional footprint will be minimised h The flowlines and static umbilicals will be surface-laid which will reduce the physical impact of flowline and umbilical installation on seabed habitats h Dynamically positioned vessels will be used for pipelay and piling operations, therefore no anchor mounds will result from SURF and FPSO installation activities
FPSO replacement The replacement of the existing FPSO with a new FPSO will require the removal of the 14 mooring lines currently present and installation of 20 new mooring lines and suction anchors. The potential exists for placement of the new suction anchors to result in some long-term habitat loss (for the life of the development) as the original substrate under the anchors will no longer be available to benthic species. It should also be noted that the suction anchors from the existing FPSO will not be removed and will be left in-situ. There will consequently be a loss of seabed habitat related to 34 suction anchors. As described above, for other activities involving placement of structures on the seabed, some direct physical injury of benthic species and resuspension of sediments is possible.
6.1.4
Management and mitigation
The Quad204 Project is a redevelopment of the existing Schiehallion/Loyal field development, therefore much of the seabed likely to be affected by project activities will have experienced similar impacts during previous field development phases. In addition, detailed site surveys conducted across Page 6.4
November 2010
Physical Presence
6.1.5
Residual impacts
Introduction An estimate of the area of seabed likely to be directly impacted by Quad204 Project activities is given in Table 6.2. Direct physical injury of benthic species As described in Section 4.4, surveys undertaken in the Quad204 Project area and surrounding waters have reported a species-rich and relatively abundant macrofauna, dominated by annelids. For example, the Claw drill centre seabed survey (BP, 2000a) found that the fauna mainly consisted of annelids, crustaceans, molluscs and echinoderms, a
composition similar to that reported from macrobenthic communities in offshore soft sediments in the North East Atlantic area (Pearson et al., 1996). However, no species or habitats that qualify for protection (such as Lophelia pertusa) have been recorded in the area from any of the extensive surveys. As such, the limited seabed area that may be affected by the placement of structures (with resulting physical injury of benthic species) is unlikely to contain species that are of conservation significance or that would be unable to recover in a short time period. Most of the new SURF infrastructure will be placed within existing drill centre locations and route corridors and there will consequently be very little impact on previously undisturbed seabed. Biological communities are in a continual state of flux and are able to either adjust to
Activity
Drilling
Installation of SURF infrastructure
FPSO replacement
2
Area (km )
Drilling rig: 32 rig moves, 8 anchor placements per rig move with 1-2 km anchor spread Anchors: 31.6 m2 per anchor placement (Ellsworth et al., 2005), 256 anchor placements in total
0.0081
Chain: 1200 m x 10 m per anchor chain (see Note 1 below)
3.072
25 new wellheads and subsea trees with protection structures: 4 x 5 m each
0.0005
2 new manifolds with protection structures: one of 4.5 x 4 m and one of 4.5 x 5 m
0.00005
Concrete mattresses where required at flowline crossings/pipeline freespans (neither of which are expected)
Currently unknown but likely to be non-existent or very small.
12 new riser base piles: one driven pile and one suction anchor per riser, pile diameter of 1 m assumed
0.000009
5 new flowlines laid directly on the seabed, width of 1 m for each flowline assumed
0.01887
5 new flowline jumpers between 25 m and 100 m long, worst case length of 100 m and width of 1 m for each flowline jumper assumed
0.0005
2 new static umbilicals installed on seabed, width of 1 m for each umbilical assumed
0.009703
20 new mooring lines with one suction anchor per line
0.000027
14 suction anchors from existing mooring lines remain in-situ Suction anchor diameter of 1 m assumed Total area
3.11
Note 1: If the chain remains static, the impact will be constrained to the area directly beneath the anchors and chain as they are laid on the seabed. However during adverse weather, the rig floats in the swell, causing a vertical motion of the chain at its interface with the seabed, and some lateral motion between this point on the chain and the anchor. The lateral motion of the chain at worst case could be as much as 10 m where it reaches the seabed, reducing to almost zero as it approaches the anchor. Table 6.2: Estimate of the area of seabed likely to be directly impacted by Quad204 Project activities
November 2010
Page 6.5
Physical Presence disrupted conditions or rapidly re-colonise an area that has been disturbed. In addition, the negative impacts would be effected only when the infrastructure was placed on the seabed and would not continue to occur throughout the life of the development. Seabed surveys conducted around the Quad204 Project area reveal no evidence of recent anthropogenic disturbance (Gardline, 2007). As such, it is anticipated there that there would no significant negative residual impacts related to the direct physical injury of benthic species as a result of placement of infrastructure within or on the seabed. Any anchor mounds that are generated will eventually be incorporated into the sediment through bioturbation and sediment transport processes. Significant erosion of anchor mounds is considered to start when the seabed critical velocity reaches 0.35 m/s (UKOOA, 1999). Seabed currents in the Quad204 Project area are strong at around 0.3 m/s; this may increase up to 1.5 m/s with the arrival of an eddy, which may persist for periods of up to several weeks (Metoc, 2002). The 100 year extreme current speed may be up to 2 m/s close to the surface but decreases with depth. In depths greater than 350 m, however, there is a risk of sudden severe currents (that are both infrequent and unpredictable) close to the seabed that are associated with internal waves (Metoc, 2002). It is therefore likely that significant erosion of anchor mounds will occur at times. The temporary nature of the anchor placements ensures that once the anchors have been removed from the seabed re-colonisation and recovery can begin. DTI (2003) suggest that recovery of affected areas of seabed from transient operations such as anchoring is expected to be rapid in the West of Shetland continental shelf and slope; recovery can be expected in less than five years through the actions of sediment mobility, faunal recovery and recolonisation. The anchor placements for the drilling rig will cause localised impacts which are not likely to result in large scale changes in the benthic community. Localised loss of seabed habitat The extent to which habitat loss will impact on the species present in the area will depend on the size of the area that will be excluded, the temporal extent of this exclusion (for example, permanent or temporary) and whether the area of habitat that is being excluded is unique in the area or is of significant conservation importance. The seabed type found across the Quad204 Project area is common in the West of Shetland in waters of a similar depth and the numerous seabed surveys conducted as part of earlier field development phases have not identified any habitats or species of Page 6.6
particular conservation importance (Section 4.4). Boulders which may be overturned during any installation works will continue to be available for colonisation. The physical presence of the SURF infrastructure will provide new stable hard substrata, equivalent to natural rock outcrops, in the already mixed substratum environment, which is expected to be colonised by any epifaunal and encrusting animals present in the area. This has been reported on North Sea oil platforms where calcareous and encrusting seaweeds, tubeworms and barnacles, together with bryozoans and hydroids have colonised introduced hard substrata (Forteath et al., 1982). In addition, it is known that Lophelia pertusa, the cold water coral, is found growing opportunistically on the legs of some oil platforms in the North Sea (Gass & Roberts, 2006). Experience from the Schiehallion/Loyal field development shows that infrastructure is readily colonised. Small colonies of Lophelia pertusa were recently discovered on two risers at the Schiehallion FPSO. The maximum total area of seabed that will be directly impacted by Quad204 Project activities is 2 estimated at 3.11 km . The vast majority of this area is due to anchor placement from the drilling rig and associated anchor chains. This estimate is based upon a worst case area of impact that could occur during rough weather and it is unlikely that such areas of impact would occur throughout the periods when the drilling rig is on-location. In the context of the seabed available across the West of Shetland 2 continental shelf (estimated to be 15,000 km ), this is a small area (0.021 %). Considering the nature of the habitat and species present and the small area impacted, it is therefore unlikely that there will be any significant residual impacts related to loss of available seabed habitat. Resuspension of sediments It is likely that interference with the seabed during drilling, piling and SURF installation activities will result in sediment resuspension and resettlement. The use of ROVs close to the seabed may also cause minor disturbance to the seabed and localised resuspension of sediments. It is reported that near-bed concentrations of suspended particulate material on the West of Shetland continental slope are high (DTI, 2003), at least episodically, perhaps since the majority of sediments in the area are medium sand (Aquatera, 2008) and silty and sandy sediments are more frequently naturally resuspended than higher grain size sediment. It is therefore likely that the benthic species present will be tolerant, to some extent, of sediment in the water column. Quad204 Project November 2010
Physical Presence activities will occur within existing drill centre locations and route corridors where drilling and installation activity has previously taken place. The residual effects of temporary resuspension of sediments are therefore unlikely to be significant as the species present are likely to be tolerant to elevated levels of sediment transportation. Where sedimentation does impact negatively on species, consequences are likely to be short-lived since most of the smaller sedentary species (such as polychaete worms) have short lifecycles and recruitment of new individuals from outside the narrow corridor of disturbance will be rapid. As such, recovery from the settlement of the fine particles will begin almost immediately. Residual impacts related to sediment resuspension are therefore likely to be negligible.
Transboundary impacts
6.1.6
6.2
Interaction with other sea users
Cumulative impacts
6.2.1
Introduction
In the strategic environmental assessment (SEA) undertaken for the West of Shetland area in which the Quad204 Project is located, cumulative effects are reported as those effects of other oil and gas activity including both existing activities and new activities that have the potential to act additively with each other or those of other human activities (DTI, 2003). Potential sources of physical disturbance to the seabed were identified as rig and laybarge anchoring, wellheads and templates, jacket footings, and pipelay activities including trenching and rockdumping (DTI, 2003). Of these sources relevant to the Quad204 Project, rig anchoring and pipelay are considered to account for the greatest spatial extent of seabed impact. Rig anchoring will be localised to existing drill centres, and flowline and umbilical installation will be confined to existing corridors, where in both cases development activity has already occurred (i.e. the seabed has experienced previous disturbance). The area of seabed likely to be directly impacted by Quad204 Project activities is 2 estimated at 3.11 km and is small relative to the whole of the West of Shetland continental shelf.
Installation activities and the physical presence of offshore facilities and subsea structures have a risk of interacting with other users operating within the same area of the marine environment. BP recognises that the marine environment within which the Quad204 Project is located is utilised by a number of other sea users, primarily the fishing and shipping industries. The increase in vessel presence during, for example, SURF installation activities, and the physical presence of the FPSO potentially increases the risk of vessel-vessel collision. In addition the proposed activities and vessels will exclude areas of sea and seabed from use by other sea users if outwith existing 500 m safety exclusion zones and development corridors. There is also the potential risk of gear and catch being damaged through interaction with fishing vessels and subsea infrastructure.
Cumulative and transboundary impacts
DTI (2003) reported no negative cumulative impacts from seabed disturbance, considering only the positive impact from exclusion of fishing activities. Considering the effects of seabed disturbance are generally short-lived with the habitat rapidly returning to a similar state to which it was in predevelopment, and that the majority of Quad204 Project activities will occur at existing drill centre locations and within existing route corridors, cumulative seabed impacts are considered to be negligible. November 2010
As the Quad204 Project is located approximately 35 km from the UK-Faroe median line, the activities described are unlikely to result in any transboundary impacts on the seabed. The seabed footprint for the new infrastructure will not extend much beyond the existing infrastructure footprint and the impacts identified will be localised and in some cases temporary. The recent Offshore Energy SEA for UKCS waters (DECC, 2009c) reports that seabed impacts are unlikely to result in transboundary impacts and, even if they did, the scale and consequences of environmental effects in adjacent state territories would be less than those in UK waters and would be considered unlikely to be significant.
6.2.2
Regulatory control
The key regulatory drivers that relate to the activities described in this section and which will assist in reducing the possible impact on other sea users are described in Appendix A and summarised here as follows: h Section 34 of The Coast Protection Act 1949 covers navigational safety in UK waters in relation to offshore works programmes. This Act provides that where obstruction or danger to navigation is caused or is likely to result, the prior written consent of the Scottish Ministers is required for construction, alteration or improvement of any works, and the deposit or removal of any objects or materials below the Page 6.7
56
2019 2020 2021
56
Survey vessel
Total (days)
2018
Installation, repair and maintenance vessel
2017
Construction vessel
56
Pipelay support vessel
2016
Pipelay vessel
2015
60
Tug
56
365
Riser vessel
2014
Skip/ship vessel
2013
Standby vessel
Anchor handler
Drilling rig(s)
Seismic vessel
Year
Physical Presence
75
60
120
120
29
20
849
133
133
241
20
1,667
135
20
1,485
120
40
1,575
120
40
1,455
180
60
1,521
90
30
1,111
90
30
1,466
60
20
692
308
62
365
108
20
159
62
523
123
365
108
20
123
68
518
66
366
144
40
60
95
629
81
365
180
40
365
87
365
108
60
365
87
365
144
30
366
159
366
144
30
155
36
365
36
20
60
60
100
95
35
40
35
35
40
35
Table 6.3: Estimated vessel types and number of days each will spend on-site during Quad204 Project activities
level of Mean High Water Springs. The Act also requires that where materials are lost or discarded at sea, including any materials deposited under conditions of force majeure, which were not legally deposited in accordance with the Act, every reasonable attempt must be made to recover them. In the event of objects being dropped from an offshore installation, a PON2 must be submitted to DECC, MCA and SFF. h Following the guidelines of the Safety of Life at Sea (SOLAS) Convention and the Merchant Shipping (Safety of Navigation) Regulations, information will be provided to the UK Hydrographic Office in order that a Notice to Mariners may be issued regarding the location of all associated vessels and rigs.
6.2.3
Potential impacts
Introduction The types of vessel that will be present during Quad204 Project activities and an estimate of the length of time these vessels will be on-site are shown in Table 6.3. Increased vessel presence The proposed Quad204 Project activities described in Chapter 3 will temporarily increase the number of Page 6.8
vessels present in the area. The vessels likely to be present and their duration on-site are indicated in Table 6.3. This increase in vessel activity, only some of which will be year-round (drilling rig and standby vessel), may increase the risk of a collision between vessels. Fishing interaction As described in Chapter 3 and Section 6.1.3 the Quad204 Project will add no new drill centres and drilling will take place at existing drill centres within 500 m safety exclusion zones. The footprint of the existing Schiehallion/Loyal field development and the location of proposed new SURF infrastructure are shown in Figure 3.7 in Chapter 3. It should be noted that the two new static umbilicals to be installed on the seabed will be placed in positions currently occupied by umbilicals and consequently will not increase the development footprint. It is possible that one less dynamic umbilical will be present as a result of Quad204 Project activities. The new flowlines and umbilicals will themselves exclude no additional area of seabed from use since they will be installed within existing corridors. The only additional area of seabed which will be excluded from use will be related to the replacement FPSO anchor spread which is slightly larger than the existing FPSO anchor spread (ca. 38% increase in November 2010
Physical Presence seabed area likely to be excluded from use 8).
area as it will be possible to trawl over this material.
Although the infrastructure itself will largely avoid excluding any additional seabed from use; the sea area in the immediate vicinity of the installation vessels will be unavailable for use by other sea users during the installation period. Given that activities will occur in an area that has been developed previously and has been operating for 12 years it is unlikely that the area around these vessels will impact upon other sea users.
As discussed in Section 6.1.3 the deployment of an anchored drilling rig means that there is potential for the formation of anchor mounds. Over-trawling such mounds can result in sediment being retained in the net, with potential damage to the nets, equipment and catch, and potential risks to the safety of the fishing vessel and persons on board.
The Quad204 Project will extend the life of the Schiehallion/Loyal field development to 2035, therefore the main impact in terms of loss of access will be related to the extension of the period in which currently excluded seabed will continue to be unavailable for other use.
There is the potential for objects to be lost overboard during SURF installation activities. This debris, termed ‘dropped objects’ can provide an uncharted obstacle that has the potential to damage fishing nets or fishing catch. Dropped objects are also a possibility during the drilling activities but, should they occur, will likely take place within the drill centre safety exclusion zones and are unlikely to affect other sea users.
The existing Schiehallion/Loyal field development excludes a small area of seabed relative to that available west of Shetland and Quad204 Project activities will increase this footprint by an estimated 2 3.11 km (see Section 6.1.5) Whilst the physical presence of new SURF infrastructure may not significantly impact other sea users in terms of area of seabed excluded, it is possible that fishing activity may be impacted through the introduction of potential new snagging points for fishing nets. Trawled nets can become trapped on subsea equipment, resulting in loss of fishing gear. It is possible that snagged nets may also pose a more serious threat to the safety of the fishing vessel and the crew. Such snagging can occur where there are protrusions from subsea infrastructure, where debris has accumulated against infrastructure, or where a gap, called a freespan, exists underneath flowlines. Fishing gear can also snag or be damaged by collision with manifolds and wellheads. The flowlines will be laid on the seabed within existing corridors and neither buried nor trenched thus presenting some snagging risk. Although there may be some snagging risks, particularly with respect to heavy demersal trawlers, experience from existing flowlines in the Schiehallion area indicate that there will be settlement of flowlines into the seabed sediments. Where freespans do occur, they will be eliminated through a process of post-lay inspection and correction. Manifolds and subsea trees will have ‘fishing friendly’ protection structures which will deflect any fishing gear away. Concrete mattresses may be required where conditions dictate, but this will not impact upon the ability of fishing vessels to use the
8
This is a conservative figure as it assumes loss of access to a radius equal to the length of the anchors around the FPSO, which will not actually be the case.
November 2010
Dropped objects
6.2.4
Management and mitigation
Increased vessel presence A number of mitigation measures will be employed to minimise the impact of increased vessel presence resulting from the Quad204 Project activities: h BP will ensure that the required consents and notifications are in place and will consult with relevant authorities to avoid interference with Quad204 Project activities at the Schiehallion/Loyal field development h A standby safety vessel will continue to operate at the Schiehallion/Loyal field development during Quad204 Project activities h Information on new SURF infrastructure will be communicated to other sea users through the standard communication channels including the National Hydrographic Surveyor, Kingfisher bulletins, Notices to Mariners, Admiralty Charts and FishSafe h A guard vessel will be present in the area when the existing FPSO is removed from the field until the replacement FPSO is installed Fishing interaction In addition to the measures listed above, the following additional mitigation measures will be employed to reduce the interference that Quad204 Project activities may have on fishing in the region: h BP is involved in ongoing dialogue with the fishing industry through established fishing liaison channels to ensure that all activities are documented and communicated Page 6.9
Physical Presence h The location of the anchors for the drilling rig which lie outside the 500 m safety exclusion zone will be communicated to other sea users h Allowance for potential impact loads from fishing gear has been made in the design of SURF infrastructure, and manifolds and subsea trees will have ‘fishing friendly’ integral protection structures to deflect any fishing gear away h Regular inspection surveys of SURF infrastructure will be undertaken to enable early detection of any potential snagging risks Dropped objects The following measures will be taken to minimise the potential interactions resulting from dropped objects: h All deck items will be securely stowed h The subsea trees will have integrated grated or plated roof structures which will protect them from damage by dropped objects h Procedures will be put in place to ensure that the location of any lost material is recorded and reported to DECC using PON2 notification and that significant objects are recovered h The UK Hydrographic Office will be notified of the location of any unrecoverable objects for use on charts and other nautical publications relevant to the area
6.2.5
Residual impacts
Increased vessel presence Quad204 Project activities will occur at the Schiehallion/Loyal field development, a recognised development area, which is clearly marked on navigational and fishing charts and well known to other sea users that make regular use of the area. Although, there is no statutory requirement for exclusion from a development area, other sea users are aware of the high level of oil industry activity in such areas, and additional caution is exercised.
existing Schiehallion/Loyal field development (which will continue as part of the Quad204 Project), means that shipping and fishing interests are already aware of field-specific vessel movements in the area. As a result, with the mitigation measures proposed in Section 6.2.4 temporarily increased vessel presence in the Quad204 Project area is expected to have little or no significant residual impact. Fishing interaction Snagging risks from SURF infrastructure cannot be eliminated entirely but the mitigation measures detailed in Section 6.2.4 including the use of ‘fishing friendly’ protection structures, consultation, and notices to mariners will significantly reduce the risk. The measures that BP will adopt are standard across the industry and have previously assisted in reducing the impact of oil and gas development to other sea users. SFF and Brown & May Marine Ltd (2010) report that fishing effort in the Quad204 Project area is lower than areas to the south and west due to the seabed contours and associated water depth. The majority of fishing activity in the West of Shetland is located along and around the 200 m depth contour (Chapter 4, Section 4.9.2) and as such the probability of snagging and other interference is reduced. The impact of the interaction of the highest risk fishing gears with subsea structures has been assessed during earlier field development phases and incorporated into the design of the existing subsea structures. The design of the new subsea infrastructure for the Quad204 Project will be based on previous BP West of Shetland designs. An area of seabed will be excluded from use by the fishing industry (and other sea users) during Quad204 Project activities (Table 6.4).
There will be an increase in the number of vessels present in the Quad204 Project area during drilling, SURF installation and FPSO replacement, however, these activities will generally be of limited duration and will occur over a well-defined period of time. Standard communication and notification measures will be in place to ensure that all vessels operating in the area are aware of the activities taking place (Section 6.2.4). Levels of shipping in the Quad204 Project area are low; 985 vessels frequented the waters within a 10 nm radius of the FPSO in 2009 (Section 4.10.1) largely related to the oil and gas industry. In addition, the long-term presence of the Page 6.10
November 2010
Physical Presence Activity
2
Area (km )
Period of exclusion
Drilling
Anchor spread from drilling rig
Maximum 12.5 (see Note 1)
Temporary
Installation of SURF infrastructure
Presence of DP installation vessels
Immediate vicinity of installation vessels
Temporary
FPSO replacement
Increased anchor spread from new FPSO
9.35 (see Note 2)
Life of field
Note 1: This area is based on the assumption that the anchor spread will exclude from use a circular area around the drilling rig with a radius equal to the anchor spread. The likely drilling rig has a maximum anchor chain length of approximately 2 km. Although this is also assumed to be the maximum spread, as the rig will sit in approximately 400 m of water then the spread will not extend to 2 km and this distance can thus be viewed as conservative. Note 2: This area is based on the assumption that the anchor spread will exclude from use a circular area around the FPSO with a radius equal to the anchor spread which will not actually be the case. Table 6.4: Estimated areas of exclusion related to Quad204 Project activities
The presence of the anchored drilling rig may exclude fishing vessels from the area covered by the anchor spread for the duration of the drilling only. The anchor spread will have a maximum radius of 2 km and will temporarily exclude from use by other sea users, a maximum area of sea of approximately 12.5 km2. In the event that two anchored drilling rigs are used, twice the area currently presented could be excluded at any one time but will not increase the area temporarily excluded overall since the rigs will only be on-site for approximately half the number of days of one rig. In addition, the area immediately around any installation vessels will be temporarily excluded from use by other sea users, although some of the installation work will take place within 500 m safety exclusion zones from which other vessels would ordinarily be excluded. Other installation work will take place within existing flowline corridors, further reducing any impact. An area of sea will also be excluded from use by the fishing industry (and other sea users) by the anchor spread of the new Quad204 FPSO. This will exclude 2 approximately 9.35 km from use over the lifetime of the development, but the majority of this area (8.86 km2) is excluded currently by the presence of the existing Schiehallion FPSO. As this is the only loss of access over the life of field, this additional exclusion of approximately 0.5 km2 is also the total additional loss of access resulting from the Quad204 Project. This area is at the centre of the existing Schiehallion/Loyal field development and is used far less than waters further from the development area. The area excluded by the Quad204 Project represents only a small area of the entire fishing November 2010
area available in the West of Shetland region.and as the fishing industry does not rely heavily on the area in which the Quad204 Project is located, an extension to the life of the field is unlikely to result in any residual impacts. Anchor mounds, if formed, will tend to be incorporated into the sediment through the erosive and redistributive action of locally energetic seabed currents, bioturbation and general sediment mobility (see Section 6.1.5). Anchor mounds from drilling rigs are considered less of an issue by the fishing industry than the larger anchor mounds associated with anchored pipelay vessels. Anchored pipelay vessels will not be used for the Quad204 Project as DP vessels will be deployed. Due to the temporal nature of the anchor mounds, it is likely that the risk to fishing vessels from anchor mounds in the Quad204 Project area is limited. Since the existing Schiehallion/Loyal field development, where Quad204 Project activities will occur, is already well-established, the additional SURF infrastructure to be installed is very unlikely to disrupt previously unaffected fishing activity. Considering the mitigation measures employed (including design of SURF infrastructure and ongoing dialogue with the fishing industry) there are unlikely to be any significant negative residual impacts. Dropped objects The mitigation measures described in Section 6.2.4 reduce the likelihood that objects will be dropped onto the seabed. In the unlikely event that a Page 6.11
Physical Presence significant object is dropped, BP will initiate its recovery. As a result there are likely to be no residual impacts associated with the presence of debris on the seabed.
6.2.6
Cumulative and transboundary impacts
Cumulative impacts The increased vessel activity associated with the Quad204 Project activities will occur within an established development area of which the fishing industry and other sea users that use the region are well aware. Considered alongside the low levels of shipping in the Quad204 Project area and the wide expanse of water available to navigation in the West of Shetland region, it is not expected that there will be any cumulative impacts related to increased vessel presence. DTI (2003) reports that exclusions and snagging risks to the fishing industry are cumulative to those resulting from natural obstructions, shipwrecks and other debris. The proposed new SURF infrastructure will be added to an area where existing SURF infrastructure is in place. Loss of access to other sea users for the life of the development will be limited to the slightly extended anchor spread of the new 2 Quad204 FPSO (0.5 km increase) since all other infrastructure will be placed within existing route corridors and 500 m safety exclusion zones. In terms of the total sea area accessible to the west of Shetland, this area of direct loss is clearly very small; for example, the continental shelf covers an area of approximately 15,000 km2 and the fishing grounds available on the continental slope would increase this further. As such, significant cumulative loss of access to other sea users is considered unlikely. Any restriction on area use by the anchor spread from the mobile drilling rig(s) will be temporary as anchors will be removed when the rig leaves the development area.
Transboundary impacts The SEA for the region (DTI, 2003) reports that there are no identified transboundary effects in which environmental consequences in a neighbouring state are overwhelmingly due to activities resulting from the proposed 22nd round 9 licensing . The recent Offshore Energy SEA for UKCS waters (DECC, 2009c) reports that impacts related to physical presence are unlikely to result in transboundary impacts and, even if they did, the scale and consequences of environmental effects in adjacent state territories would be less than those in UK waters and would be considered unlikely to be significant. There will be no transboundary vessel movements and given the distance to the UK-Faroe median line (35 km) it is very unlikely that the Quad204 Project will lead to transboundary impacts related to the presence of additional vessels. As any areas excluded from use by other sea users will be restricted to Quad204 Project activities taking place within the existing Schiehallion/Loyal field development area, none of which will extend across the UK-Faroe median line, transboundary impacts related to fishing interaction are also considered unlikely. Considering the mitigation measures to be applied and the distance from the UK-Faroe median line, it is very unlikely that there will be any transboundary impacts resulting from dropped objects.
As with loss of access to seabed, there will be some cumulative increase in snagging risk in the vicinity of the development. However, with the mitigation measures described above, including ongoing dialogue with the fishing industry, the cumulative impact is considered negligible. The additional exclusion zone for the Quad204 Project will represent only a minor increment to the existing area covered by exclusion zones to the west of Shetland. Considering the mitigation measures to be applied, it is very unlikely that there will be any cumulative impacts resulting from dropped objects.
9
The licensing round with which this particular SEA coincided.
Page 6.12
November 2010
Discharges to Sea
7
Discharges to Sea
BP aims to reduce the impacts of discharges on the environment, with emphasis placed upon pollution prevention and impact minimisation at source. This section assesses the residual discharges from the Quad204 Project and the management and mitigation measures employed in order to adhere to legislation and achieve BP’s goals.
7.1
Introduction
The existing Schiehallion FPSO has been onstation since 1998 and will be replaced by a new FPSO as part of the proposed Quad204 Project. The design philosophy of the Quad204 Project is to incorporate lessons learned and opportunities for improvement from the existing Schiehallion FPSO to the design of the new Quad204 FPSO. Key design features of the Quad204 FPSO, such as reinjection of at least 95% of produced water and its associated chemicals (and a target of 98% reinjection) coupled with a target of 15 mg/l dispersed oil in water have been implemented to reduce residual levels of discharges to sea. During the ENVID process (see Section 5.4) several discharge types were regarded as being potentially significant and therefore required detailed impact assessment and management. A full quantitative assessment and modelling of discharges is provided below where appropriate and in Appendix F. Discharges to sea can occur during the drilling, installation, commissioning and operational phases of the Quad204 Project. The environmental impact of the following discharges has been assessed: h Drilling discharges h Mud and cuttings h Cement h Installation and commissioning discharges h Operational discharges h Produced water h Produced sand h Drainage Potential impacts from drilling discharges (drilling muds, cuttings, and cement) are discussed in Section 7.3 and aqueous discharges during installation, commissioning and production are discussed in Section 7.4. Two options for the hull coating system on the November 2010
FPSO are under consideration: an anti-foul coating which is copper-based and a foul-release coating which is silicone based. Discharges to sea from the hull coating system are expected to be negligible and are therefore not discussed further in this chapter. Discharges associated with vessel operations (e.g. sewage discharges) are also considered to have a negligible environmental impact and are therefore not considered further.
7.2
Regulatory control
h DECC has implemented the OSPAR Decision, relating to the Harmonised Mandatory Control System for the Use and Discharge of Offshore Chemicals, on the UKCS under the Offshore Chemicals Regulations 2002 (OCR). Under these Regulations, operators require a permit to use and discharge chemicals. Operators need to assess the risks to the environment which might arise from the individual chemical use or discharge. A formal process of risk assessment is required, such as can be undertaken using the Chemical Hazard Assessment and Risk Management (CHARM) algorithms. Substances posing little or no risk (PLONOR) to the marine environment do not need a risk assessment. These assessments are detailed in an application known as a PON15. Some chemicals receive priority according to less favourable toxicity, biodegradation and bioaccumulation properties, and are known as candidates for substitution, and their use is more strictly controlled and requires detailed justification. Once final engineering details and chemical requirements are known, and prior to the commencement of any drilling, installation, commissioning and production operations, BP will submit the relevant PON15 applications, supported by appropriate detailed chemical risk assessments, to DECC under the OCR in order to obtain approval prior to chemical use and discharge. As part of the PON15 process, BP will target candidates for substitution to ensure that chemicals are chosen that are fit for purpose but also have a low environmental hazard profile. Chemicals will only be used in accordance with the PON15 permit conditions and according to BP’s internal requirements. BP is committed to minimising the environmental effects of the chemicals used and discharge and chemicals will be selected based on the decision-making criteria described in Section 2.1.1, which considers health and safety, environmental, economic and technical Page 7.1
Discharges to Sea factors. h The Offshore Petroleum Activities (Oil Pollution Prevention and Control) Regulations 2005 (OPPC) were introduced by DECC in order to meet the OSPAR goal of reduction in discharges of oil to the marine environment from offshore industries. These regulations require a permit to be in place prior to the discharge of any reservoir oil to sea. During drilling operations this will apply, for example, where any drill cuttings are discharged that contain reservoir hydrocarbons, or during well testing and cleanup if there are discharges of water. During the production phase, oil released in drainage, produced sand and produced 10 water discharges must be permitted under the OPPC regulations. The permitting of the oil discharges to sea requires the operator to show that the operations are consistent with Best Available Techniques (BAT) and operated to Best Environmental Practice (BEP), and to carry out an environmental impact assessment of the discharge. Through this OPPC process operators are required to illustrate ongoing improvement and compliance with current BAT and BEP and low potential for adverse environmental impact. The PARCOM recommendation (PARCOM 86/1) for a 40mg/l hydrocarbon emissions standard for installations which applies to hydrocarbon concentration in effluents not covered by MARPOL, i.e. formation water, ballast water and drainage water from the production unit is also regulated under the OPPC permitting process. Should only discharges of oil to sea be required, the relevant OPPC applications will be submitted by BP to DECC at the appropriate time. h The Merchant Shipping (Prevention of Oil Pollution) Regulations 1996 implement MARPOL Annex 1 in the UK and control oily discharges from any vessel activity (e.g. machinery space drainage). The Regulations require all vessels to have in place a UK or International Oil Pollution Prevention Certificate
10
The current base case for any new development is zero discharge of produced water. The DECC produced water reinjection (PWRI) availability target is 95% by volume. The dispersed oil-in-water content of produced water must not exceed a monthly average of 30 mg/l (or maximum of 100 mg/l).
Page 7.2
(UKOPPC or IOPPC) to demonstrate compliance. h The Merchant Shipping (Prevention of Pollution by Sewage and Garbage from Ships) Regulations 2008 are also in place for sewage treatment and discharge and may apply to some offshore installations and vessels. Potential future regulatory changes The OSPAR Convention has a goal of “zero harmful discharge” by 2020 and therefore a reduction in the harmful components of produced water discharges will be required by that time. The UK is currently working within OSPAR to determine how this will be regulated in practice. OSPAR is developing criteria and methodological standards for a risk-based approach for produced water discharges, and a proposal for a new OSPAR measure is expected to be discussed/agreed in 2011. There is also the potential for limits on radioactivity to be set for produced water discharges, which will depend on the outcome of an ongoing North Sea monitoring/measurement programme.
7.3
Drilling discharges
7.3.1
Potential impacts
Discharges to sea during drilling operations include mud, cuttings, cement and associated chemicals and may result in the following impacts: h Increased suspended solids in the water column h Alteration to the seabed topography and sediment structure by settlement of the cuttings and mud on the seabed resulting in a change in the grain size, which can impact the oxygen movement within the sediment h Alteration of the seabed environment which can result in a change to the benthic community due to h smothering and lack of oxygen as a result of deposition h impairment of feeding and respiratory system of organisms resulting from mud and cuttings deposition and increased concentrations of suspended particles near the seabed h Toxic impact may result from the mud and additive chemicals used in the drilling operation Discharge of chemicals may also occur during well workover or intervention activities (see Section November 2010
Discharges to Sea Hole size
Typical well length (m)
Typical cuttings quantity (tonnes)
Typical mud system
Current cuttings disposal options
42”/36”
87
163
Sweeps
To seabed at top hole (riserless)
26”
200
192
Sweeps
17 ½”
1,250
500
WBM
Cuttings cleaned from rig to recover WBM and Note 1 disposal of cleaned cuttings overboard
12 ¼”
1,440
274
OBM
8 ½”
987
89
OBM
Cuttings cleaned on rig to recover OBM. Cleaned cuttings transported to shore for further treatment Note 2 and disposal to landfill.
Total cuttings (per generic well)
1,217
Note 1: It is possible that for some well designs, this section may be drilled riserless and cuttings deposited on the seabed. Note 2: Offshore treatment of OBM contaminated cuttings is being considered as an option (see Section 2.5) Table 7.1: Generic mud types and quantity of cuttings for a typical Schiehallion well
3.2.7). The plan is to drill the first hole section (42”/36”) riserless, i.e. mud is not circulated back to the rig via a riser for re-use, with seawater and bentonite sweeps with the returns discharged directly at the seabed. The 26” hole section will also be drilled riserless with seawater and bentonite sweeps before displacing the hole to KCl/Polymer mud and then running 20” casing. The 17½” interval will be drilled with the riser in place and all the mud and cuttings returned to surface. The majority of the drill cuttings will be removed from the circulating mud system by the solids control equipment and then discharged overboard. It is assumed in the supporting modelling that the cuttings will be discharged from the Mobile Offshore Drilling Unit (MODU) via an outlet pipe 15 m below sea level; the exact arrangement depends on the rig selected and will be detailed in the PON15 application that accompanies the drilling operation. Typically OBM is used for the lower sections (12¼" and 8½" sections) as it is more suitable for drilling through shales which are usually found at this depth, for lubricating the longer drill string and for better well performance properties when drilling through the reservoir formation. Low toxicity mineral oil is planned to be used as the base fluid for these mud systems. OBMs reduce torque and drag as well as maintaining well bore quality and optimum conditions for high quality fracture identification, data acquisition and minimum formation damage. OBM contaminated drill cuttings will be shipped to shore for treatment and disposal (see Chapter 11). Offshore treatment of OBM cuttings using hammer mill treatment with the November 2010
cuttings and mud solids discharged to sea is another option under consideration (see section 2.5) and this has recently been successful on nearby Foinaven wells. If offshore treatment of OBM is undertaken the environmental impacts will be assessed in PON15B applications as appropriate. Table 7.3 summarises typical mud types to be used and the estimated quantities of cuttings that are likely to be generated from a typical Schiehallion well (a standard Schiehallion well design is assumed for the Quad204 wells). Table 7.3 presents the total maximum quantity of WBM cuttings generated for the 25 infill development wells in Phase 1 of the Quad204 well programme. The decision regarding the drilling of the mid hole section (17½”) will be undertaken during detailed well planning. Table 7.2 presents the total maximum quantity of OBM cuttings generated for the 25 infill development wells in Phase 1 of the Quad204 well programme.
Page 7.3
Discharges to Sea Year
No. of infill wells to be drilled
Top hole section WBM cuttings to seabed (tonnes)
Mid hole section WBM cuttings to sea (tonnes)
2014
3
1.065
1,141
2015
3
1.065
721
2016
3
1.065
918
2017
5
1,775
1,784
2018
4
1,420
1,152
2019
3
1,065
1,107
2020
3
1,065
800
2021
1
355
274
Total
25
8,875
7,897
Total WBM cuttings (Phase 1)
21,375
Table 7.3: Estimated quantity of WBM cuttings
Chemicals are used in drilling a well to maintain the desired technical composition of the mud to facilitate the drilling of the well. Chemicals are included in mud formulations to lubricate the drill bit and in circumstances such as those that occur during lost circulation and stuck pipe. During the cementing phase of drilling a well, a number of chemicals are added to the mixwater (used to form the cement composition) to ensure the final cement has the necessary physiochemical (e.g. corrosion resistance, viscosity, pore size, etc) and mechanical properties (e.g. tensile and
compressive strength) to achieve the desired performance. There are routes for these chemicals to be discharged to sea e.g. either as part of a drill mud formulation or cement mix water, and therefore the potential exists for toxic impact on the marine environment. Cementing operations may involve small discharges of cement when cementing the tophole sections back to the surface and when the cement unit is cleaned between each cementing operation. It is anticipated that the majority of cement will be mixed and used as required, and as a result there
Year
No. of infill wells to be drilled
Lower hole (12¼ “) section OBM cuttings to shore (tonnes)
Lower hole (8¼”) section OBM cuttings to shore (tonnes)
2014
3
822
267
2015
3
822
267
2016
3
822
267
2017
5
1,370
445
2018
4
1,096
356
2019
3
822
267
2020
3
822
267
2021
1
274
89
Total
25
6,850
2,225
Total OBM cuttings (Phase 1)
9,075
Table 7.2: Estimated quantity of OBM cuttings
Page 7.4
November 2010
Discharges to Sea should be limited discharges of any mixed cement or mixwater. All cement discharges from the deeper well sections would take place via the route for WBM cuttings discharges, i.e. back to the drilling rig.
7.3.2
and isolate unstable formations and different formation fluids. Each casing is cemented into place to form a seal between the casing and the formation. Most cement remains in the well bore, but some will be discharged to the seabed during the setting of the top section and in flushing the cement system. The volumes of material discharged are extremely small and these will be assessed prior to the cementing operation via the PON15 assessment process.
Management and mitigation
In line with BP policy, the following will be addressed during detailed well design and final chemical selection for all drilling related operations:
In addition to new well construction, well workovers and interventions will be carried to maintain and repair the existing well stock. Workovers and interventions will involve the use of chemicals and the return to surface of wellbore debris. Depending on the application, fluids and chemicals may be returned to surface for treatment and discharge; shipped to shore for appropriate disposal or reuse; remain in the wellbore or reservoir; or be produced to the FPSO.
h Selection of WBM chemicals with least potential for environmental impact h Environmental risk assessment on the use and discharge of chemicals and identification of measures to reduce risk h Cuttings contaminated with reservoir hydrocarbons will be retained onboard for appropriate treatment ashore h Reuse of mud system to reduce discharges
As the most likely well problem in existing Schiehallion well stock is sand fill in the lower completion, it is most likely that a well intervention
Steel casings are installed into the well throughout the drilling operation to provide structural strength
Category
Drilling chemicals Used
Discharged
Cementing chemicals Used
Discharged
Completion/ clean-up
Totals
Used
Discharged
Used
Discharged
Sand screen completion PLONOR (E)
512
462
2,707
82
274
9
3,493
553
Other E
10
0
0
0
8
1
18
1
D
0
0
0.1
0.1
0.1
0
0.2
0.1
C
0
0
0
0
2
2
2
2
Gold
1
1
188
8
36
0
225
9
Silver
0
0
0
0
0
0
0
0
Z
2,450
0
0
0
0
0
2,450
0
Gravel pack completion PLONOR (E)
762
752
2,707
82
938
448
4,407
1,282
Other E
65
60
0
0
14
4
79
64
D
0.4
0.4
0.1
0.1
1
0
1.5
0.5
C
0
0
0
0
2
2
2
2
Gold
81
81
188
8
90
8
359
97
Silver
0
0
0
0
10
0
10
0
Z
1000
0
0
0
0
0
1,000
0
Table 7.4: Summary of generic chemical use and discharge during well operations
November 2010
Page 7.5
Discharges to Sea to remove sand and repair the sand face completion will be attempted or the well will be sidetracked. Interventions involve the downhole reentry inside the existing completion, and will be carried out to maintain and enhance the value of the existing well stock. Based on historical information, a workover every year (for an average duration of 60 days) has been built into the drilling schedule. This will be within the new well drilling schedule from 2014 to 2021 (Phase 1) and then batched in groups of 5 and 4 in 2026 and 2030 respectively. The exact timing of these workovers is subject to change, but the total number is believed to be representative. A generic summary of chemicals that will be used during drilling, cementing and completion operations is given in Table 3.1. The environmental impact of any chemical use during well operations will be addressed in the PON15B which will be submitted at the appropriate time for the Quad204 Project wells. BP policy on chemical use requires that the use and discharge of each chemical should be considered at least once a year and discussion will be held with suppliers about the availability of more “environmentally benign” chemicals on an ongoing basis through the project life cycle.
7.3.3
Residual impacts
Burial of benthic organisms can result in mortality depending on the depth of cuttings deposition. Filter feeding organisms (for example, hydroids and bryozoans) that rely on suspended particles as a source of food may be more vulnerable to the smothering effects of the drilling discharges than scavenger organisms that rely on the deposition of suspended material. Barite consists of barium sulphate, an insoluble, chemically inert mineral powder that normally contains measurable concentrations of several trace metals. Barium is considered “biologically unavailable” and is unlikely to have a measurable effect on the benthic fauna (Jenkins et al, 1989; Hartley, 1996). The environmental impact of other trace metals will depend on their concentration in the WBM contaminated cuttings, which in turn depends partially on the geological source of the barite. However, Neff et al (1989) found that metals associated with drilling mud barite are virtually unavailable to marine organisms that might come into contact with discharged drilling fluids. An assessment of the potential of the drilling programme to cause the impacts described above was conducted with the aid of the Dose-related Risk and Effects Assessment Model (DREAM)
Page 7.6
model (SINTEF). This model was used to asses the potential dispersion and environmental impact of the drilling discharges from Phase 1 of the Quad204 Project infill well programme. The modelling assessed both the drilling of a single four string well and the drilling of all 25 wells in the Phase 1 programme. An overview of the modelling is given in Appendix G. The model impact assumptions are based on considerable scientific work undertaken by SINTEF and others. There are many processes that occur in the marine environment that will act on the various components of the discharge as shown in Figure 7.1. The water column was predicted to be impacted by the drilling of a single 4 string well over a period of 6 days at the beginning of the 25 days taken to drill the well. This impact was predominantly (98%) due to the presence of fine barite and bentonite particles in the lower water column (below 240 m) from the riserless drilling of the 36” and 26” sections of the well. There is by contrast a limited (<2%) predicted toxic impact from the drilling of the 17½” section (drilled with a riser and discharge 15 m below the sea surface), nevertheless no significant and lasting environmental impact is predicted. These predicted impacts are likely to be in excess of those actually seen because the modelled impact is based partly upon the interference of particulates on the feeding of zooplankton. As the suspended particulates in the model are spatially restricted to the lower water column it is unlikely that there will be any significant adverse impact on zooplankton feeding as these will generally be located higher in the water column. The water column impacts are expected to be short term and localised which aligns with the findings published from impact studies for drilling (such as the 1,000 fold dilution is expected within 10 minutes of discharge (Neff, 2005)) and the DREAM-related research (e.g. 2006 TNO report regarding the potential environmental impact on the water column of weighting agents in drilling mud). Although there are a number of fish and shellfish that can be found in the vicinity of the Quad204 development, the area is not used widely as a fish spawning or nursery area. Therefore it is anticipated there is unlikely to be significant impacts on commercial fish species from the drilling activities.
November 2010
Discharges to Sea
Figure 7.1: Processes in the marine environment that are modelled in DREAM (Source: SINTEF).
Dredging activities lead to re-suspension of sediments and an increase in the suspended solids loading in the same way as the discharge of drilling fluids. OSPAR have carried out a summary review of the types of dredging activities and the amounts of material dredged and deposited in 2008 (OSPAR, 2009). Increase in turbidity due to increased suspended solids loading is recognised as a short-term impact, the implications of which are determined by the level of contaminants in the dredged sediments. The contaminant loading of the WBM and chemicals to be used in the drilling activities will be risk assessed as part of the PON 15 process prior to use of the chemicals. The output of this assessment will be applied to minimise potential adverse impacts associated with chemical composition of the solids in the water column will be minimised. The position of the cuttings on the seabed was predicted to cover a wide area although this predominantly resulted in a layer of less than 0.01 mm thick the presence or affect of which is unlikely to be detectable in the environment. Nearer the well the area of deposition with a thickness of between 1 mm and 130 mm was centred on the well and had an elongated shape approximately 440 m by 140 m in the SW-NE by NW-SE direction. The potential impact of the settlement of drilling derived solids is in alignment with published November 2010
studies (Neff, 2005) which also show localised accumulation of solids near the well. SINTEF has coordinated research into how grain size changes from drilling discharges affect the benthos (such as the Akvaplan-niva report (SINTEF, Undated)). In order to quantify the potential impact from the changing of the sediment composition the change in the median sediment grain side is commonly used. As such the median grain size is an important descriptor of the receiving sediment as well as the material deposited. The environmental surveys of the Quad204 area indicate a highly variable sediment composition and therefore it was difficult to define a single value for the receiving environment in the modelling. However based upon the available data, a value between 300 and 549 microns was considered appropriate to use. This was used as a basis for the comparison of the change in sediment composition due to the cuttings and barite deposition. The particle size distribution for the barite and cuttings used in the modelling are shown in Figure 7.2. Smothering or burial will be limited to the areas of sediment with the higher deposition, e.g. 1 cm thickness. This indicates in the areas where there is limited deposition, the infaunal organisms should not be smothered and should be able to move through this surface layer of deposition. Review of Page 7.7
Discharges to Sea
Figure 7.2: Particle size distribution used in drilling discharge modelling
the limited information available on the sensitivity of the benthic organisms found at the Quad204 location (Chapter 4) to increased suspended solids and smothering (MARLIN database) suggests that although some smothering is likely to result in mortalities there are species present that will tolerate and recover from the impacts. The infaunal burrowing brittlestar Amphiura filiformis would probably relocate (MARLIN, 2010) to its preferred depth within the new sediment and other species e.g. Ampelisca sp. would tolerate elevated suspended solids loading. These species are likely to be tolerant of some degree of smothering, but there may be a decline in species richness within the community close to the drill site. The feeding structures of the amphipod e.g. Haploops may become clogged with increased suspended solids and therefore feeding would be temporarily limited. The infaunal Amphiura filiformis can tolerate increases in silt by using mucous secretions to remove the fine particles. As the increased suspended solids loading in the water column is not expected to be long term, the impact of this on the benthic species is considered to be low. As there will be no deposition of an impermeable Page 7.8
layer on the seabed the infaunal species are expected to be able to relocate through the deposited material to their preferred depth. Jones et al. (2007) carried out studies at the existing Schiehallion site and found that significant disturbance (reduced abundance and diversity) was limited to within 50 m of the drill site. Studies at the deeper and muddier Laggan drill site, West of Shetland, on the impact of physical disturbance on the megabenthic species by drilling activities (Jones et al. 2006) also showed that there were high levels of physical disturbance (smothering) of the seabed 50-120 m from the drill site, and that this resulted in variable levels of disruption to the megabenthic community. Measurable effects on the megabenthos have however been recorded up to 200 m from the drill site, however the data suggest that these effects are limited (Jones and Gates, 2010).The diversity of the megabenthic community was decreased towards the drill site, as is typical of areas of physical impact. The impacts expected from the deposition of drill solids are expected to result in impacts of diversity and abundance on the megabenthic species which would be limited to the area of deposition November 2010
Discharges to Sea estimated by the modelling. The magnitude of the changes in diversity and abundance were dependant on the mobility of the taxa investigated (Jones and Gates, 2010).
deep-sea holothurian in the Schiehallion area showed that this deposit feeder had a key role in the turnover and maintenance of the quality of the sediment (Hudson et al., 2004).
The recovery of the seabed will start immediately once the deposition is finished i.e. on the last day of deposition around day 10 of the drilling operation. The benthic infauna e.g. the burrowing brittlestar Amphohiura sp and the burrowing suspension feeding amphipod Haploops sp. (amongst the ten most abundant species in the area) will start bioturbation immediately. Recolonisation of smothered sediments will also start immediately from mobile organisms moving into the impacted area such as the holothurian Stichopus sp also found in this area. Recent studies have been carried out in this area by the SERPENT team in the Schiehallion area, showed that there is considerable potential for sediment turnover by the infaunal organisms in the area, which will enhance the recovery of any impacted seabed. In addition studies in this area on the
The impact from the deposition is not expected to result in significant adverse impacts on the seabed other than immediately at the well location. There is likely to be a good potential for recovery of any seabed impacted by sedimentation of drilling solids due to the species present. The potential for recovery from the full drilling programme is discussed below. When the cumulative impacts of the entire phase 1 infill well drilling programme were considered by the modelling it was necessary, due to the limitation of the model, for the entire programme to occur within 1 year. This is very different from the actual duration of this programme which is scheduled to occur over 6 years. As such the modelling compounds the impacts of the impact of the phase 1 drilling programme. Size distributions of particulates used in the Quad 204 drilling
Figure 7.3: Map of the deposition profile from the Quad204 phase 1 drilling programme overlaid on existing well and survey locations
November 2010
Page 7.9
Discharges to Sea discharge modelling of the predicted deposition of the drilling mud and cuttings from the phase 1 drilling programme is shown in Figure 7.3. This map shows that there is unlikely to be a cumulative impact from the Quad204 phase 1 infill well drilling programme due to the distances between the four drill centres (Central, North, West and Loyal) involved. When this is considered against the longer period of the drilling programme (than simulated by the model) it is highly unlikely that there will be a cumulative impact from the drilling activity. The predicted impact at each of the drill centres considered is similar to that modelled for a single 4 string well and discussed above.
7.4 7.4.1
Installation and commissioning discharges Potential impacts
Flowlines, umbilicals and risers Following completion of new flowline installation operations, the production and water injection flowlines will be flooded with filtered, inhibited and dyed seawater. The flooding operations are normally conducted from a support vessel located over the drill centre location, in order to minimise vessel activity at the FPSO. As with previous precommissioning activities with the Schiehallion FPSO, it is important to note that there will not be one discharge event or location, but a series of discrete discharges throughout the different stages of the subsea pre-commissioning programme. Details of the new flowlines to be laid are given in Table 7.5. The largest discharges are likely to be associated with the flooding operations. In addition to the discharges to sea, there will also be some discharges to the FPSO process system (post tiein leak testing of the production system and pre production start-up). New and existing risers will also be filled with inhibited seawater. The connection of risers to flowlines and to the FPSO will result in some leakage of the fill water during this operation. Umbilicals which have been previously disconnected, prior to the arrival of the new FPSO, will be filled with an agreed control fluid in the hydraulic cores and glycol in the chemical cores. The hydraulic fluid will be discharged through the control system to the sea during commissioning. The glycol will be discharged into the well and then back to the FPSO. Fill fluid for the gas lift lines will be discharged to the FPSO. It is also expected that the water in the flowlines will be displaced to the FPSO through the pigging loops for the production flowlines. Page 7.10
3
Flowline
Length (m)
Diameter (m)
Volume (m )
Loyal
5,806
0.024
206.4
NWAD
2,835
0.024
100.8
West
2,819
0.024
64.7
Central
2,564
0.024
91.1
Central
2,700
0.024
96.0
Table 7.5 Pipeline volumes to be discharged from installation and commissioning activities
Subsea structures Subsea structures such as manifolds and Xmas trees may contain hollow structural steel members and compartments. These members and compartments are generally flooded during deployment to subsea in order to avoid high external differential hydrostatic pressures. The flooding route is normally via holes drilled at predetermined locations that allow water ingress whilst at the same time allowing venting of trapped air. The flooding holes are capped or plugged with plastic or rubber grommets, which contain flexible slots. The flexible slots are designed to allow water ingress and air egress whilst preventing internal fluids from escaping once the initial flooding operations have been completed. To prevent internal corrosion of the steelwork through initially oxygenated seawater and microbial species, chemical inhibitor sticks or bags are inserted into the flooding holes before subsea deployment of the structure. Biocide, oxygen scavenger and dye sticks are the expected chemical groups to be required for these operations. The design of the flooding holes is intended to limit the loss of any chemical / seawater mix and therefore negligible discharge is expected. No further consideration is therefore given to chemicals released from these structures here although an impact assessment for these discharges will be carried out as part of the PON15 permit application. As previously described, chemicals will be required during subsea installation and pre-commissioning operations. Under the terms of the Pipeline Works Authorisation (PWA), consent is required prior to any discharge (including hydrotest water) being made and submission for a consent to use and discharge chemicals (PON15) are required under the Offshore Chemicals Regulations 2002. The appropriate risk assessment for the use and discharge of these chemicals will be covered in the November 2010
Discharges to Sea
30
Oil to sea (tonnes/year)
25 20 15 10 5
2035
2034
2033
2032
2031
2030
2029
2028
2027
2026
2025
2024
2023
2022
2021
2020
2019
2018
2017
2016
2015
0
Year Note: There will be no production between 2Q 2014 and 3Q 2015. Existing FPSO production will cease in 1Q 2014 with new FPSO production expected from 4Q 2015. Figure 7.4: Forecast oil to sea from the Quad204 project
PON15 permitting system. Work on identifying alternative chemicals where required is ongoing. The focus is on selecting as far as practicable, the use of low dosage, low risk chemicals.
7.5
Operational discharges
7.5.1
Potential impacts
Produced water The production regime from the Schiehallion/Loyal area is characterised by the production of significant water volumes which is expected to increase over life of field. Well design has been optimised to reduce the aquifer breakthrough which will minimise the water produced through field life. As with the existing Schiehallion FPSO, the disposal route for the Quad204 FPSO produced water is re-injection into the reservoir via PWRI. The PWRI system on the existing Schiehallion FPSO has experienced problems in the past from sand generation and reliability, resulting in higher than forecast oil discharges to sea. The new PWRI system for the new FPSO has been designed to overcome these challenges and to provide a minimum availability of 95% and a target availability of 98% (see Section 3.5.7). The estimated produced water production from the existing Schiehallion development and the forecast Quad204 development discharge is shown in November 2010
Figure 3.6 and Table 3.5 in Chapter 3. The oil to sea assuming compliance with the 30 mg/l legislative requirement is shown in Figure 7.4. This shows that by the application of lessons learned from Schiehallion to the design and adoption of the PWRI system on the Quad204 FPSO the discharge of produced water including oil will be considerably reduced as the produced water will be injected back into the reservoir. In addition, this system will be available immediately and will result in a minimum of commissioning discharges as the PWRI wells are already in place in the existing Schiehallion infrastructure. Production from the new FPSO will result in the requirement for chemical use and discharge. Information relating to anticipated chemical application is summarised in Table 7.6. It should be noted that this is not an exhaustive or definitive list of chemicals that may be required. Examples of specific chemicals currently used in the Schiehallion development are also provided, but only generic descriptors are provided for the Quad204 development at this stage. The dosages of the chemicals will be refined when production is initiated. The chemical products required will be reviewed prior to commencement of operations and their use and discharge will be addressed by means of a PON15D application. In summary, chemical injection facilities will be provided on the new FPSO facilities to address:
Page 7.11
Discharges to Sea Generic chemical type
Application
Example chemical (currently used at Schiehallion)
Colour band / OCNS group / 100% PLONOR
Methanol
Injected into the well streams and import gas to inhibit hydrate formation
TROS 518 (95% MeOH 5% Water Blend)
E
KI-3821
Gold (Sub)
E
Subsea Scale /Corrosion Inhibitor
Injected into the well streams to prevent scale formation and corrosion of the subsea infrastructure.
Future
A spare tank, pump and chemical injection swivel paths are provided for any subsea chemical that may be required in the future Water Injection
Calcium Nitrate
Injected into the water injection stream to prevent growth of Sulphate reducing bacteria in the reservoir and hence reduce H2S levels in the production streams.
SOURTREAT SR45
Biocide
Injected into various locations to mitigate against microbial growth.
BIOTREAT 4535 - To be replaced
Silver (Sub)
Antifoam
Injected into the seawater deaeration tower if there are problems with foaming.
EC9163A
Gold (Sub)
O2 Scavenger
To achieve 10ppb O2 content in the seawater for injection.
TC1018 (Ammonium bisulphite – 75%)
(45%wt solution)
Topsides Process Demulsifier
Injected to aid bulk oil/water separation.
PHASETREAT 6252
Scale inhibitor
Injected to reduce scale formation in topsides systems.
SCALETREAT 8063
Gold
Reverse Demulsifier
Flocculates oil droplets in produced water stream to improve hydrocyclone performance.
EC6029A
Gold
H2S Scavenger
Injected to reduce levels of H2S in the oil and gas streams. **H2S scavenger and its by products are water soluble
SCAVTREAT 7103
Silver
Table 7.6: Example of proposed production chemicals
h Hydrogen Sulphide prevention
h Scale formation
h Hydrogen Sulphide removal
h Corrosion protection
h Oxygen removal
h Microbiologically induced corrosion
h Separation of emulsions
h Microbial fouling
h Foaming problems
h Hydrates
3.6.11). Treatment will be carried out to recover oil and ensure that water achieves the required dispersed oil in water specification of 15 mg/l before being discharged overboard. The slops tanks will also recover water from crude oil tank washing. Run off from non process areas will be drained directly overboard. Bunding and controlled disposal will ensure there is division between process and non-process areas. Subsea control fluid
Drainage The design of the open drains system on the new FPSO is still underway. However, it is anticipated that the majority of liquids from open drains will be collected in the FPSO slops tanks (see Section Page 7.12
Currently the hydraulic fluid, Oceanic HW-540, is used to control the subsea valve systems that are tied in to the Schiehallion FPSO. This hydraulic fluid contains substitutable substances according to the OSPAR HMCS pre-screening scheme. In line with the UK’s strategy for the phase out of November 2010
Discharges to Sea substitutable substances under the OSPAR agreement, the Quad204 Project objective is to have a replacement control fluid in place prior to first oil in 2015. This will involve testing a fluid that is compatible with all the subsea components, HW540 and meets the relevant environmental regulations. A substantial amount of work was undertaken on the Schiehallion FPSO in 2006 to establish the suitability of Castrol Transaqua HT2. Confirmation on whether this fluid (HT2) is the best option for the Quad204 FPSO will be undertaken early in construction phase of the project, with appropriate component testing on the selected fluid being undertaken following this. Produced Sand As significant quantities of sand have been produced in the Schiehallion and Loyal fluids and the possibility of increased sand in the future, maximum facilities for sand handling and clean-up were included in the specifications for the design. In addition to the cyclonic sand removal devices as currently present on the Schiehallion FPSO, sand jetting for sand removal from vessels and cyclonic devices for sand removal from produced water have also been included in the new FPSO topsides process. Sand screens are also included for the completion of the wells, which will help minimise the production of sand. In addition all new wells will have sand detection installed on the trees and there will be sand detection at the top of the risers. These measures have been included at the design stage to minimise the problems that would be encountered in the production of sand from the wells within the water injection system. The forecasted sand production rate from the combined Schiehallion and Loyal fields as given in -3 the Quad204 Project Basis of Design is 8.5 kg m -3 total liquids, with peaks up to 28.6 kg m Worst case projections of sand discharges are 6.6 tonnes per week in a single batch; a quantity which is insignificant when compared to the discharge from the drilling operation of between 2,900 t to 4,700 t per well for 25 wells over a 6 year period. The sand will be recovered from the production separators and the produced water treatment system using cyclonic devices as for the current Schiehallion vessel. As a result of lessons learned from Schiehallion the new sand cleaning system has been designed to include hot produced water jetting to improve the mobilisation of sand and prevent patches of residual sand building up in the device and enhancing recovery of oil from the sand. This improvement of the design of the cyclonic device will result in a reduction of the discharges to sea. The resulting sand will then be stored prior to cleaning and batch discharge below November 2010
the waterline through a single open pipe.
7.5.2
Management and mitigation
Produced water During normal operations, the produced water will be treated in the produced water treatment facilities and routed to the produced water reinjection swivels in the FPSO turret. The PWRI injection system will be designed to achieve 95% availability (with a target of 98%). The new FPSO will have an off spec cargo tank to hold treated produced water during short term system upsets and recycle this back through the produced water treatment system once available. Incorporation of this into the design of the new FPSO will provide a buffer for the produced water management system by reducing discharges to sea if the PWRI system is unavailable or the produced water for discharge is out of specification and requires reprocessing. When the injection system is unavailable for longer term system upsets, produced water will be discharged overboard. Historically the Schiehallion and Loyal crude oil and water mixture has proven difficult to separate in the original facilities as the viscosity is higher than originally expected for a variety of reasons, including heat, necessary residence times, vessel motion and emulsion forming tendencies. Tests have been carried out on the Schiehallion and Loyal fluids and the studies have shown that the crude oils form emulsions. The design of the new Quad204 separation facilities and PWRI will use lessons learned from the issues with the current Schiehallion FPSO and from the nearby Foinaven FPSO to achieve a better processing of produced fluids and improved PWRI availability. Any environmentally critical equipment will be identified and planned maintenance routines will be put in place to ensure that such equipment is operated and maintained to a level that achieves objectives and targets, complies with environmental consents and minimises adverse risk to the environment. As the PWRI system is expected to have at least 95% uptime the discharge of produced water is not expected to occur for long periods of time. The new FPSO will be designed so that any oil content is minimised to 15 mg/l as the target oil in water specification of the system, which is below the legislative requirement of 30 mg/l. The required cleanup specification (non-soluble oil-in-water content of 15 mg/l (maximum)), will be achieved with the adoption of BAT as applicable for the particular operating conditions of FPSO West of Shetland operations. The produced oil in water content will be continuously monitored on the FPSO to ensure this target is achieved. As with the Page 7.13
Discharges to Sea other discharges to sea BP will apply for the appropriate OPPC and PON15 permits. Modelling with the DREAM model (SINTEF) was used to support the assessment of the dispersion and potential impact of the chemicals in the produced water if the PWRI system was unavailable. The results of this are shown in Appendix F. The modelling was based on a scenario that assumed that the entire maximum annual unavailability (5%) occurred in one block of time (18.25 days). This is a situation that is highly unlikely to occur during normal operation. In addition to the dispersed oil, the produced water will contain formation water constituents and chemicals not removed by the produced water treatment facilities. The potential adverse environmental impact from the constituents in the produced water discharge was investigated by modelling.
Produced water components
occurring constituent are shown in the Table 7.7. Environmental risk assessment will be conducted on the use and discharge of chemicals and measures identified to reduce risk as part of the PON15 permitting system. Chemicals with high environmental risk (candidates for substitution) will not be used. An auditable chemical assessment and selection process will be used. The production chemical package considered in this modelling consisted of four products and was based upon the data in their CEFAS templates; a scale corrosion inhibitor (KI-3821), a scale inhibitor (SCALETREAT 8063), a reverse demulsifier (EC6029A) and an H2S Scavenger (SCAVTREAT 7103). These chemicals were chosen as they partition into the water phase and are routinely used and therefore likely to be present in the produced water. Using the CEFAS template toxicity is conservative as this toxicity is for the most toxic component rather than for the overall chemicals.
Average measured concentrations mg/l (see Note)
4°00'W
2°00'W
0°00'E
0.513
Phenols C0-C3 alkylated
0.760
Phenols C4-C5 alkylated
0.375
Phenols C6-C9 alkylated
0.193
PAH 2-3 ring
0.267
PAH 4-5 ring
0.004
Copper
0.003
Zinc
0.038
Nickel
0.004
Lead
0.003
Cadmium
0.0002
Mercury
0.0002
61°00'N
Naphthalene
60°00'N
6.861
Water Column Risk Map: Total
60°00'N
BTEX
61°00'N
9.9
62°00'N
Aliphatic
62°00'N
100 km
18d 05:00 4°00'W
2°00'W
0°00'E
Figure 7.5: Water column risk map for continuous 11 discharge of produced water (9.9 mg/l Scenario ) for 18 days based on the extreme worst case unavailability of PWRI scenario
Note: Average of the last 8 biannual produced water samples Table 7.7: Schiehallion produced water constituents
The produced water components modelled were taken as the average values of the last eight biannual ‘aromatic’ analyses taken pursuant to the OPPC consent requirements for the Schiehallion field, from the 2nd half of 2006 to the first half of 2010. The concentrations of these naturally Page 7.14
11
Dispersed oil in water composition of the discharge was calculated from the average values of the last eight biannual analyses taken pursuant to the OPPC consent requirements for the Schiehallion field, from the 2nd half of 2006 to the first half of 2010.
November 2010
Discharges to Sea In Figure 7.5, Figure 7.6 and Figure 7.7 the potential environmental impacts associated with the discharge of produced water when the PWRI system is out of commission are presented.
discharge. Nevertheless the relatively high contributions from phenol and PAH are recognised and further investigation will be done as part of the project Define stage to understand the presence of these compounds, their impacts and any potential mitigation measure that can be applied going beyond current legal requirements. Potential radionuclides in produced water
Figure 7.6: Water column risk cross section (9.9 mg/l Scenario) (along vector in figure) for continuous discharge of produced water for 18 days based on the extreme worst case unavailability of PWRI scenario
EIF_PAH2 0.7% EIF_MERCURY 0.2% EIF_LEAD 0.1%
Contribution to risk, EIF = 2170 Scaletreat8063 0.0% KI3821 0.2%
EIF_CADMIUM 0.0% EIF_COPPER 1.4% EIF_ZINC 0.7%
EC6029A 0.0%
Scavtreat7103 1.3%
EIF_ALIFATER 1.2% EIF_PHENOL1 0.1% EIF_NAPHTHL 0.3% EIF_PAH1 15.7%
EIF_BTEX 0.2%
EIF_BTEX EIF_ALIFATER EIF_PHENOL1 EIF_NAPHTHL EIF_PAH1 EIF_PHENOL2
EIF_PHENOL2 6.8%
EIF_PHENOL3 EIF_ZINC EIF_COPPER EIF_LEAD EIF_CADMIUM EIF_MERCURY EIF_PAH2
EIF_PHENOL3 71.0%
KI3821 Scaletreat8063
Production water may contain radioactivity, which has originated in reservoir formation water as a result of the decay of the naturally occurring radionuclides Uranium-235, Uranium-238 and Thorium-232. The radionuclides arising from the decay chain may be present in the production water as particulate matter or held in the form of a true solution. There is a requirement under the Radioactive Substances Act 1993 to determine whether water co-produced with hydrocarbons in a hydrocarbon facility (produced water) is radioactive as defined in Schedule 1 of RSA93. If the produced water is not radioactive, then no further action is necessary. However, if the produced water is radioactive, then the amount of radioactivity discharged to the sea or re-injected must be quantified and become subject to either an appropriate exemption order or an authorisation issued under Section 13 of RSA93. Scale prediction work has shown that Schiehallion and Loyal produced waters have a low scaling tendency (CaCO3 only). BaSO4, SrSO4 and CaSO4 scales are not predicted. Therefore, significant (if any) production of NORM is not expected.
EC6029A Scavtreat7103
Figure 7.7: The contributions to the EIF of produced water components in the 9.9mg/l Scenario
The potential impact of the produced water discharge was mitigated by the rapid dispersion of produced water comments due to the strong currents and winds in the Quad204 area. The risk to the water column was relatively small and predominantly (78.7%) due to the natural alkyl phenols present and the PAHs (16%). This risk to the water column would be further reduced in reality because the PWRI downtime is more likely to be distributed through the year as small periods of time during which the off spec cargo tank would be used to hold produced water and buffer the need to discharge to sea during short periods of PWRI unavailability. It is predicted that any toxic impacts would be very short term and risk to sensitive biota would reduce to <5% in 30 hours following cessation of November 2010
As part of an extensive UKCS study of LSA/NORM in produced waters, samples from Schiehallion were analysed for radium-226, radium-228 and Polonium-210. No radium-226 or radium-228 were detected, and the polonium-210 level was recorded as below 0.000039 Bq/g (ITS, 2003), i.e. well below the limit of 0.0259 Bq/g set under Schedule 1. Therefore, the produced water from Schiehallion is considered out with the controls under the Radioactive Substances Act 1993. Produced sand Produced sand from the cyclonic devices on the FPSO will periodically need to be batch discharged to sea at the surface. Although the phenomenon of fine solids produced along with oil and gas is frequently described as ‘produced sand’, the particle size distribution shown below (Figure 7.8) and taken from Schiehallion FPSO operations, is more correctly a silt, and will disperse readily in the marine environment.
Page 7.15
Discharges to Sea sinking into the sediment. Any impact from produced water discharges is expected to be localised and limited to short term impact due to the dilution experienced and the mobility of the water column organisms.
Particle Size Distribution 20
Volume %
18 16 14 12 10 8 6 4 2 0 10
50
75
100
125
150
175
200
250
300
350
400
450
500
Particle Size: microns
Figure 7.8: Particle size distribution from Schiehallion FPSO operations
These discharges will involve far smaller quantities of particulate material than the drilling discharges described above and are unlikely to result in smothering and changes in grain size at the seabed due to the highly energetic environment in the Quad204 area and the depth of the water at the FPSO location. To quantitatively assess the potential impact of sand discharges, the water column and sediment models of the MEMW model were used; the results of which are presented in Appendix F. The modelled particle size distribution of the sand discharged by the Quad204 FPSO was derived from ongoing Schiehallion operations. An extreme worst case scenario was investigated that assumed 6.6 tonnes of sand containing 1% Schiehallion oil attached to it, will be discharged in a batch process over 3 hours each week. This scenario is based upon the highest sand production rate and an oil on sand value that is 6.6 times the design specification of the new FPSO and therefore by far the worst case. The predicted deposition layer from the sand is so thin (0.02 mm) that no impact is likely. In addition given normal sediment recovery rates and sediment deposition rates in the area, it is unlikely that long term batch discharge of sand will have a significant effect on the sediments in this area. As this extreme worst case discharge scenario is predicted not to cause an impact on the environment it is highly likely that the lower discharge rates of sand containing maximum specified 0.15% oil on sand from the new FPSO will also have no predicted impact.
7.5.3
Residual impacts
On the occasions when the PWRI system is out of commission and it is not possible to contain the produced water, it is expected that the produced water discharged to sea will be immediately diluted 30-100 times within the first 10 m and 1,00010,000 times within 500-1,000 m (OGP, 2005). Compounds that are soluble in water dilute rapidly in the sea, with particulate matter eventually Page 7.16
The major constituents of produced water are inorganic salts, but it also contains low concentrations of trace elements and residual quantities of dispersed and dissolved hydrocarbons. The process of dilution, evaporation, adsorption/precipitation, biodegradation, and photo-oxidation tend to reduce the concentrations of compounds in the produced water in the receiving environment and thus decreases their potential toxicity to marine organisms. The poly aromatic hydrocarbon (PAH) components of the produced water are of the most concern because of their likelihood of being more persistent in the marine environment; the toxic effects of PAHs vary but include non-polar narcosis, phototoxicity and biochemical activation that can cause mutagenic, carcinogenic and teratogenic effects. The discharge of hydrocarbons from oil and gas activities is unlikely to have large-scale environmental impacts (OSPAR, 2009). As with the other constituents of the produced water, the discharge of hydrocarbons in produced water may have short-term and localised impacts in the water column. BP will apply for an OPPC consent for the Quad204 FPSO for the discharge of hydrocarbons in produced water and a PON 15D application for the use of chemicals. Considering the control and mitigation measures proposed, it is not considered that any of these discharges causes a significant long term impact on the environment.
7.6
Cumulative and transboundary impacts
Due to the highly dispersive environment in the vicinity of the Quad204 FPSO and the low volume and periodic nature of the discharges, no significant cumulative or transboundary impacts are expected with the Quad204 Project from discharges to sea. The drilling footprint is not expected to overlap with those from other developments, and the produced water that will be discharged when the PWRI system is out of commission and chemical use and discharge will be in line with regulations. Although there is some fish spawning in the vicinity of the proposed Quad204 FPSO, these spawning areas form part of larger offshore areas used for spawning and no species have been identified as November 2010
Discharges to Sea exclusive to the area. Studies have shown that the discharge of production chemicals will disperse rapidly and that effects of direct exposure are limited (DTI, 2001a). There has also been no evidence of indirect effects through biomagnification (DTI, 2001a). It can therefore be considered that cumulative impacts associated with the proposed Quad 204 Project can be considered negligible.
November 2010
Page 7.17
Discharges to Sea
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Page 7.18
November 2010
Underwater Noise
8
Underwater Noise
The methodologies available for assessing the potential impacts that man-made underwater noise may have on marine mammals have seen a period of rapid development in recent years, although the scientific evidence remains incomplete and inconclusive. This EIA has utilised up-to-date scientific information and applied the most recent JNCC guidelines in an attempt to assess the significance of any potential impacts from the Quad204 Project. This chapter also includes an assessment of whether or not the proposed operations will cause disturbance of European Protected Species (EPS) as defined in the Offshore Marine Regulations.
8.1
Introduction
Underwater sound is generated by a number of natural sources including rain, breaking waves and also to a lesser extent biological sources for example the vocalisations of marine-life. The combination of all noise sources: hydrological, physical and biological contributes towards the ambient noise, or background noise. Globally, ambient noise levels have increased, this has been particularly associated with increases in the utilisation of the oceans for shipping and other industrial activities, including oil and gas. A number of oil and gas activities can generate high levels of underwater sound, attention has been most focused on the activities which generate impulsive sound, this includes pile driving, seismic exploration and the use of underwater explosives in decommissioning activities. Any form of offshore development will invariably require the use of vessels, such as specialist construction vessels, supply vessels and support vessels. Sound from vessels is a type of continuous noise and tends to be the dominant contributor to background noise levels in the North Sea. Marine mammals (including the baleen and toothed whales) use sound to communicate with members of their own species. Toothed whales also use sound to build up an image of their environment and to detect prey and predators through echolocation (Tyack, 2008). The introduction of additional noise, man-made or otherwise, into the marine environment has the ability to interfere with the ability of such animals to communicate and to determine the presence of predators, food and underwater features (OSPAR, 2009). The potential impact of sound upon marine receptors has been receiving increased attention in the last few years. The principal concern has been November 2010
regards to the impact that man-made sound has upon sensitive marine mammal species, although there are also concerns over impacts to other types of marine life including fish. There are a number of activities associated with the Quad204 Project that will be notable sources of underwater noise, this includes pile driving, seismic surveys, drilling of production wells, vessel movements and pipelay activities. These activities (and others outlined below) have the potential to increase underwater sound levels and cause acoustically induced noise impacts upon marine mammals and other acoustically sensitive species in the vicinity of the project. The UK oil and gas industry recognises that more information is required concerning the effects of sound emissions and currently has a joint industry project in place to better define and understand the environmental risk of offshore operations with respect to noise (OGP, 2010).
8.2
Regulatory control
The Habitats Directive provides for the establishment of a European network of protected areas to tackle the continuing losses of European biodiversity. As the inspiration for the EC Habitats Directive, the Bern Convention had an influence on The Conservation (Natural Habitats &c.) Regulations (1994) (Habitat Regulations, HR) which were introduced to implement those parts of the Habitats Directive not already covered in UK st legislation. As of 1 April 2010, The Conservation of Habitats and Species Regulations 2010 replace the HR in English and Welsh waters out to 12 nm, consolidating the various amendments to date. In Scottish waters out to 12 nm the 1994 regulations will continue, except for matters where power has not yet been devolved to the Scottish Parliament, in which case the 2010 Regulations will apply. The new Regulations do not make any substantive changes to existing policies and procedures other than in relation to the establishment of the Marine Management Organisation. The Habitats Directive has been transposed into UK law for offshore oil and gas activities by The Offshore Petroleum Activities (Conservation of Habitats) Regulations 2001 (as amended). The Offshore Marine Conservation (Natural Habitats, &c.) Regulations 2007 (the Offshore Marine Regulations, OMR), amended in 2009 and 2010, apply the conditions of the Habitats Directive to all offshore activities for waters within UK jurisdiction but outwith 12 nautical miles of the coast. The Habitats Directive places a duty on the Secretary of State to propose to the European Page 8.1
Underwater Noise
The same species is noted on more than one occasion if evidence from more than one set of measurements was available
Figure 8.1: Typical cetacean audiograms showing a number of species for which such data are available (Adapted from Tech Environmental, 2006 based on Nedwell et al., 2004)
Commission a list of sites which are important for either habitats or species listed in Annexes I and II of the Habitats Directive respectively. The bottlenose dolphin, harbour porpoise and grey and harbour seals are listed on Annex II of the EC Habitats Directive and as such the UK government is obliged to identify areas of importance for these species. Both the HR and OMR prohibit the deliberate capture, injury, killing or disturbance of any wild animals of a European Protected Species. Certain animals, including all species of cetaceans, are listed in Annex IV as in need of strict protection (called European Protected Species, EPS). The OMR 2009 amendment revised the existing disturbance offence. Specifically, Regulation 39(1) of both the HR and OMR provide that a person is guilty of an offence if he deliberately captures, injures, or kills any wild animal of an EPS or deliberately disturbs wild animals of any such species. The legislation defines an act of disturbance as any which is likely to impair the ability of the affected species to survive, breed or reproduce, or to rear or nurture their young. In the case of animals of a hibernating or migratory species, any activity which might interfere with these activities is classed as a disturbance. In addition, any activity that may significantly affect the local distribution or abundance of the species to which they belong constitutes a disturbance.
Page 8.2
It is considered likely that some EPS (all cetaceans) and some of the species listed in Annex II of the EC Habitats Directive (porpoise) may occasionally be present in the vicinity of the Quad204 Project area (see Chapter 4 for more details).
8.3
Marine mammals in the Quad204 Project area
The communication calls of toothed whales (odontocetes) are mainly in the moderate to high frequencies between 1 kHz and tens of kHz, producing sounds across the widest frequency bands that have been observed in animals (Southall et al. 2007). Toothed species also have highly developed echolocation systems that operate at intermediate to very high frequencies (tens of kHz to 100+ kHz, Southall et al. 2007). As a result of the wide range of sounds emitted, estimated auditory bandwidths are likely to cover a relatively wide frequency range. Toothed whales can be divided into two broad categories based on their auditory bandwidths: h Mid-frequency cetaceans, including common, bottlenose and Risso’s dolphins and killer, sperm and long-finned pilot whales, with an auditory bandwidth of 150 Hz to 160 kHz h High-frequency cetaceans, including porpoise, with a bandwidth of 200 Hz to 180 kHz (Southall et al. 2007)
November 2010
Underwater Noise Activity/Vessel
Piling operations (hammer)
Source noise level (peak dB re1mPa @ 1m unless specified)
Dominant frequencies produced (Hz)
228-251 dB(0-peak) @ 1m (piles 1.5 – 4.5m)
Temporal nature
Short-term installation activity
243-257 dB (p-p) @ 1m (piles 1.8 – 4.5m) highly dependant on pile size and installation method, low frequency. Seismic operations
224- >240 dB but highly dependant on specifics of seismic array, low frequency
Short-term exploration activity
Semi-submersible drilling rig
154 dB (rms) @ 1m
10 - >1,000
Short-term installation activity
Tanker
179 - 181 dB (rms) @ 1m
<15
Operational activity
Dynamic Positioning (DP) pipelay/installation vessel
154 – 180 dB (rms) @ 1m
29 – 70
Short-term installation activity
Rock placement vessel
179 dB (rms) @ 1m
10 – 100
Short-term installation activity
Anchor handling tugs
164 – 170 dB (rms) @ 1m
50 – 1,000
Short-term installation activity
Helicopters (Bell 212 altitude 152 m)
149 dB (rms)
22 (tonal)
Installation and operational activity
Installation support vessels
136 dB (rms)
20 – 1,000
Short-term installation activity
Supply vessel (with thrusters)
1/3rd octave broad band source level 191.5 dB re 1 µPa
20 – 1,000
Installation and operation activity
Table 8.1: Noise sources relevant to the Quad204 Project (Breitzke et al., 2008; Wyatt, 2008; Nedwell et al., 2007; ITAP, 2005; Nedwell et al., 2002; Richardson et al., 1995)
A typical audiogram for odontocete species is shown in Table 8.1. The odontocete species occurring around the Quad204 Project area with the most regularity and highest densities that could be affected include the Atlantic white-sided dolphin and the long-finned pilot, killer and sperm whales. Baleen whales (mysticetes) appear to be more sensitive to low and moderate frequency sounds (this species group has an estimated auditory bandwidth of 7 Hz to 22kHz) and lack the high frequency echolocation system common to toothed whales (Southall et al. 2007). Recent evidence suggests that some vocalisation may occur at higher frequencies (e.g. humpback whale, Au et al. 2006) and that functional hearing capabilities may extend up to 30 kHz (Ketten et al. 2007), but these are likely to be exceptions for this group. A typical audiogram for baleen whales, few of which exist for this group of species, is shown in Figure 8.1. The sensitivity of baleen whales to lower frequencies could make them more susceptible to effects from industrial noise than toothed varieties whose sensitivity seems poor at the lower frequencies (Southall et al. 2007) where most industrial noise is concentrated (Marine Mammal Commission, 2007). The only baleen whales likely November 2010
to be present with any regularity in the wider Quad204 Project area are the sei and fin whales (see Chapter 4). Seals (Phocids) are unlikely to be found with any regularity in the Quad204 Project area due to its offshore location and will not be considered further in this assessment.
8.4
Noise sources and potential impacts
8.4.1
Noise sources from the Quad204 Project
Vessel activity is generally regarded as the main source of anthropogenic noise in the ocean but oil and gas shipping represents a considerable proportion of the gross vessel tonnage and is therefore also a significant contributor to ocean noise. Noise sources often associated with offshore oil and gas activity and which are likely to occur as a result of the Quad204 Project are described in Table 8.1. Scientific studies have documented both the presence and absence of behavioural responses of marine life to various sound signals from Page 8.3
Underwater Noise anthropogenic activities. Biological significance of sound signals has not been well defined in many animal groups that are much more amenable to research than marine species on which there is considerably more data available. One of the primary sources of uncertainty stems from difficulties in determining the effects of behavioural or physiological changes on an animals’ ability to survive grow or reproduce (NRC, 2005).
Sound can also potentially induce a range of nonauditory effects, such as damaging body tissues, especially air filled cavities including swim bladder and muscle tissues (reviews in Richardson, et al. 1995). However, research and understanding of non-auditory effects of sound on marine receptors is still in its infancy (OSPAR, 2009).
To date, no universal conclusion on the effect of sound can be drawn or is likely to emerge in the near future (OSPAR, 2009). The problems of investigation and study of marine animals is compounded given the inherent difficulties of observing them in their natural environment. Given the above constraints, it is highly unlikely that the effects of sound on marine animals, particular at the population level, will ever be fully understood.
The noise sources detailed in Table 8.1 that may interact with marine life in the Quad204 Project area are discussed in further detail in the following sections.
However, it is generally accepted that exposure to anthropogenic sound can induce a range of adverse effects on marine life. These range from insignificant impacts to significant behavioural changes and also include non-injurious type effects including masking of biologically relevant sound signals, such as communication signals. Activities that generate very high sound pressure levels (SPL) can cause auditory injuries and other types of physical injury and, in some circumstances, lead to the death of the receiver (Richardson et al. 1995, Southall et al. 2007). Organisms that are exposed to sound can be adversely affected over a short time-scale (acute effect) or a long time-scale (chronic effect). When evaluating the effects of underwater sound sources the properties of the waveform that are important are peak pressure, received energy, signal duration, spectral type, frequency range, duty cycle, kurtosis, rise time and directionality. Sound can cause a number of distinct auditory effects on marine receptors, these include either inducing a temporary reduction in hearing sensitivity (termed Temporary Threshold Shift, TTS) which is recoverable with time, or cause a permanent reduction in hearing sensitivity (termed Permanent Threshold Shift, PTS), this is a nonrecoverable auditory impact. A number of the impact criteria put forward for marine mammals specify thresholds capable of causing both TTS and PTS. The basic concept in deriving these values is to measure the faintest sound an animal can hear, then expose the animal to a noise stimulus and retest hearing. Measuring the noise just loud enough to cause a temporary reduction in hearing sensitivity gives a conservative estimate of the exposure that could pose a risk of injury if sustained or increased. Page 8.4
8.4.2 Assessment of noise sources
Drilling Underwater sound is generated from drilling and production platforms through the transmission of the vibrations of the machinery and drilling equipment such as pumps, compressors and generators that are operating on the platform. Semi-submersibles operating in this area will occasionally use thrusters in addition to anchors to maintain position over the drill site. Where the drilling rig or production platform is reliant upon support and supply from other standby and supply vessels these are often equipped with dynamically positioned thrusters and powerful engines and therefore contribute towards the overall noise level of drilling and production activities. During periods of drilling, other types of equipment, such as the turntable, will be in operation, in addition to the standard machinery such as generators and pumps which would operate at a higher power than non-drilling periods. The operation of additional equipment at higher energy levels changes the level of noise and tonal frequencies transmitted into the water column during drilling periods. The sound levels from drilling activities are likely to be masked by the vessels, supply boats and tugs associated with the drilling operation. Seismic Seismic activity is considered one of the key vectors of noise impact with regards to offshore oil and gas activity. Numerous reports exist in the literature that apparently document injury to, or changes in the behaviour of, marine mammals (e.g. Miller et al. 2009, Gailey et al. 2007, Gordon et al. 2003). As such, a number of measures are adopted as standard practice by the industry to mitigate for any potential negative effects; these include temporal restriction, ‘soft start’ and the deployment of marine mammal observers. The adoption of the JNCC seismic guidelines and additional consent requirements such as the November 2010
Underwater Noise utilisation of Passive Acoustic Monitoring (PAM) reduces the risk of seismic operations causing injury to marine mammals. Importantly, each individual seismic operation is the subject of specific assessment through the Petroleum Operation Notice (PON) 14a application process which will consider the guidelines and best practice criteria applying at the time. Rock dumping and pipelaying In order to provide protection of oil and gas seabed infrastructure it is possible that rock dumping or placement of concrete mattresses may be necessary. There have been relatively few studies that have measured underwater sound from such activities. Nedwell and Howell (2004) state that measurements of rock placement noise are scarce with only one being known to the authors. This measurement of a dedicated rock placement vessel could not detect noise from the rocks being placed on the seabed above that of the vessel engaged in the rock dumping. The sound levels generated from the laying of concrete mattresses and rock are expected to be dependent upon the noise characteristics of the construction vessel involved in the operation.
Subsea infrastructure installation The placement and installation of subsea infrastructure on the seabed has the potential to generate high levels of underwater sound, but the level of sound is highly dependent upon the method of installation. It is recognised that using an impact pile driver can generate high levels of underwater sound, so where possible the use of alternative methods for securing structures will be chosen where favourable sediment conditions permit. There are three types of installation method that will be considered, the first is gravity structures, such as the manifolds, these use angled penetration and will therefore not make use of any piles. Suction anchors are another form of securing structures and these will be used in the installation of the mooring lines and risers, these anchors displace air and drive the anchor into the seabed. It is expected that the sound levels generated by the placing of structures onto the seabed by their own weight and the use of suction anchors will cause negligible levels of underwater noise, and this is likely to be indistinguishable from the associated construction vessels. The third form of installation is piling and this will be considered in a later section.
Aircraft There is an abundance of information of airborne sound levels from commercial helicopter flights, however there have been only a few studies which have taken measurements of the underwater noise generated by helicopters. Low-flying helicopters used to transfer personnel will increase underwater noise levels especially during take-off and landing when flight heights are lower. Helicopter sound originates from the disturbance of the sea surface by the down wash from the blades and by coupling of blade noise directly into the sea. Although helicopter sound is fairly broad band (0-20 kHz), the lower frequency sound is much more pronounced (up to 200 Hz). Levels and durations of sounds received underwater from passing aircraft depend on the altitude and aspects of the aircraft, receiver depth, and water depth. In general, peak received level in the water as an aircraft passes directly overhead decreases with altitude (Richardson et al. 1995). The number of helicopter flights may increase for the transportation of personnel and equipment to the Quad204 Project area during drilling and installation activities and this may cause a transient increase in underwater sound levels along flight corridors and landing areas.
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Vessels A number of vessels will be required for the installation of the subsea structures and for the drilling activities which will utilise computer controlled dynamic positioning (Chapter 6, Table 6.3). Dynamic positioning involves the use of a number of thrusters. In general, ship’s thrusters are recognised as a significant source of continuous noise. During the operational phase, shuttle tankers will be required to offload hydrocarbons from the FPSO. These large commercial vessels have powerful engines that mainly produce low frequency noise. Acoustic broad band source levels typically increase with increasing vessel size, with smaller vessels (< 50 m) having source levels 160-175 dB (re 1µPa), medium size vessels (50-100 m) 165180 dB (re 1µPa) and large vessels (> 100 m) 180190 dB (re 1µPa) (OSPAR 2009, Richardson et al. 1995). Using data collected from the Schiehallion and Foinaven fields, Swift and Thompson (2000) reviewed potential sources of industrial noise in the region. They reported levels of noise similar to those previously recorded from drillships and supertankers. Broad band noise events appeared Page 8.5
Underwater Noise to be associated with periods of rig movements and shipping and were considered most likely to have been generated from thrusters and propellers on both rigs and supply vessels. Narrow band noise events were not associated with rig in-hole activities nor were they associated with rig movements or shipping; these events appeared to coincide with gas turbine use on the Schiehallion FPSO and may have been the result of gas turbine loading whereby the hull of the FPSO acts as an effective couple between vibrating machinery and the water column. As most of the frequency of the acoustic energy radiated from large commercial vessels is below 1 kHz, it is recognised that there is potential for these sound levels to mask the hearing of marine mammals that produce and receive sounds in this range, and the group of marine mammals of most concern are the baleen whales. The potential for masking at higher frequencies (1 to 25 kHz) exists when the vessel is in close proximity to the animal, but the potential for permanent hearing damage from occasional exposure is very low. Vessel noise associated with the drilling and installation activities (limited time period only), and offloading and production of hydrocarbons (long period of time (i.e. the life of the field)) will contribute to background noise levels in the area. Noise impacts are examined further in Section 8.4.6. Pile driving Piles are likely to be required to secure a number of structures on the seabed and will be used where other installation methods are likely to be unsuccessful. Each of the newly positioned risers will require two piles to allow tethering to the seabed (one driven pile and one suction anchor) per riser (Section 3.4.5). It is also possible that the piles to which the existing riser tethers are attached may require replacing with new piles, the likelihood of which will be determined by inspection surveys during installation of the new riser piles. The maximum number of driven piles to be installed for both the new and existing risers is 21. The assessment and discussion in subsequent sections will consider the installation of these 21 piles. Although final project decisions regarding the specifics of the piling programme have not yet been made, previous experience of BP projects in similar conditions suggest that the rate of hammering is likely to be between 22 and 30 blows per minute with maximum strike energy of 3000 kJ. It is also anticipated that each pile will require approximately 2 - 3 hours pile driving to complete installation. Page 8.6
Acoustic data were collected during pile driving activities associated with the installation of the Clair Phase 1 development, located approximately 90 km to the north east, this involved pile driving of 2.5 m diameter piles into the seabed. The highest values of sound pressure level and sound exposure level were collected at 889m from the pile driver, the sound pressure level was 199 dB re1µPa @889 m and sound exposure level (SEL) 2 was 173 dB re1 μPa -s @889m were collected (White 2010). These levels at this distance are lower than any marine mammal exposure thresholds for physical injury and temporary threshold shift according to the Southall criteria. As the piles required to secure the risers to the seabed will be considerably smaller in diameter than those that were used for the Clair Phase 1 jacket it is expected that the sound pressure and exposure levels generated will also be lower.
8.5
Noise modelling and potential impact
8.5.1
Introduction
On the basis of the review of potential noise sources associated with the Quad204 Project, it is considered that pile driving represents the greatest potential for impact on marine mammals from noise emissions, and the long term presence of vessel noise also needs further consideration. Underwater noise modelling has been conducted to better understand the spatial extent of these effects.
8.5.2
Piling noise
Pile driving activities are known to generate very high source levels 228-251 dB (0-peak) re 1μPa@ 1 m and produce relatively broad band frequencies in the range 20 Hz – 20 kHz (Nedwell et al. 2007). However, much of the data presented for pile driving is based on modelled predictions, with very few empirical data sets existing for underwater pile driving measurements. The effects of noise will depend on the strength of the sound source and the sound transmission condition of the receiving environment, as well as the proximity of any animals to the noise and their ability to detect the frequencies produced. A simplistic formula to predict piling source levels was put forward by Nedwell, Workman and Parvin (2005, in Talisman, 2006). This formula uses the diameter of the pile, which has been found to be one of the principal parameters in influencing underwater sound levels. The formula is:
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Underwater Noise Source Level = 24.3 * Pile diameter (in metres) + 179 dB re 1μPa @1m Applying this formula for the 0.98 m diameter piles expected to be used on the risers, the source level is estimated at 202.9 dB (peak-peak) re 1 µPa @1m. This formula is only used to provide an indicative assessment of source levels and it is recognised that it is not able to accurately predict source levels for all types of pile diameter. This source level would be below all the exposure criteria for injury and auditory impacts proposed by Southall et al. (2007). In order to provide a more accurate and precautionary representation of the sound pressure level and frequency components of pile driving the predictive modelling undertaken here will apply data from a study that measured the piling noise associated with the installation of a steel jacket (ITAP 2005). For the purposes of the modelling a larger diameter pile is being used to those that are expected to be used in the installation of the risers, so this builds in an element of precaution in the assessment. The dominant piling frequencies are less than 200 Hz, and it is expected that riser piling will generate a similar spectra of frequencies with the majority of the sound pressure being generated at frequencies below 2 kHz.
frequency and sea state plus a 'local anomaly' factor in the form of a constant in the attenuation equation based on the same parameters. For the purposes of the model, the tabulated data is converted into linear form (using power and log regressions) to enable a wider range of frequencies to be calculated. The use of this data is considered to be a more reliable method for continental shelf waters than a traditional geometric model (e.g. Erbe and Farmer 2000). The data applies to frequencies in the range of 100 Hz to 10 kHz, while the model uses third-octaves from 10 Hz to 100 kHz, and the extreme ends of the range are extrapolations. These extrapolated frequency attenuation factors have been checked against other methods to assure their validity (Erbe and Farmer 2000). The modelling used has been run for a muddy sediment environment in a water depth of 400 m. As the model was developed to take into account variations in the sound speed profile with depth it is able to provide an indication of received sound levels with varying depth, the depth chosen to model sound was a depth of 350 m. The model is able to take into account sea state and weather conditions and a calm sea was chosen for when the model was run.
This model applies empirical data collected by Marsh and Schulkin (1962) that correlate frequency, sea state and noise attenuation. These data are based on approximately 100,000 observations in continental shelf waters and result in a distance attenuation factor based on
Figure 8.2: Sound pressure levels re 1µPa for a pile driving impulse over a 100km by 100km area
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Page 8.7
Underwater Noise
Figure 8.3: Piling noise sound pressure levels re 1µPa at 1/3rd octave frequency bands at a distance of 10 km (illustrated by the yellow line). For comparison, shown on the plot is an audiogram of a harbour porpoise. Marine Mammal functional hearing group
Sound Type Single pulses (e.g. explosive use)
Multiple pulses (e.g. piling)
Non-pulses (e.g. shipping noise)
Low-frequency cetaceans Sound pressure level
230 dB re: 1 μPa (0-peak)
Sound exposure level
198 dB re: 1 μPa -s (Mlf)
2
230 dB re: 1 μPa (0peak) 2
198 dB re: 1 μPa -s (Mlf)
230 dB re: 1 μPa (0-peak)
2
215 dB re: 1 μPa -s (Mlf)
Mid-frequency cetaceans Sound pressure level
230 dB re: 1 μPa (0-peak) (flat)
Sound exposure level
198 dB re: 1 μPa -s (Mmf)
230 dB re: 1 μPa (0peak)
2
2
198 dB re: 1 μPa -s (Mmf)
230 dB re: 1 μPa (0-peak)
2
215 dB re: 1 μPa -s (Mmf)
High-frequency cetaceans Sound pressure level
230 dB re: 1 μPa (0-peak) (flat)
Sound exposure level
198 dB re: 1 μPa -s (Mhf)
2
230 dB re: 1 μPa (0peak) 2
198 dB re: 1 μPa -s (Mhf)
230 dB re: 1 μPa (0-peak)
2
215 dB re: 1 μPa -s (Mhf)
Pinnipeds (in water) Sound pressure level
218 dB re: 1 μPa (0-peak)
Sound exposure level
186 dB re: 1 μPa -s (Mpw)
2
218 dB re: 1 μPa (0peak) 2
186 dB re: 1 μPa -s (Mpw)
218 dB re: 1 μPa (0-peak)
2
203 dB re: 1 μPa -s (Mpw)
Table 8.2: Southall et al. (2007) proposed injury (PTS) or TTS criteria for functional hearing groups of marine mammals exposed to discrete noise events (either single or multiple exposures within a 24-h period).
Page 8.8
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Underwater Noise Although the Marsh and Schulkin approach allows prediction of varying levels throughout the water depth, it does not take account of variations in salinity and temperature over depth. Given the uncertainties inherent in the source data, it is unlikely that incorporating reflection, refraction and sound speed effects from such variations would make a material difference to the conclusions, but if more accurate source and ambient noise levels were to be available in the future, such modelling should be undertaken to enable the noise field to be better understood. The modelled sound pressure level profiles dB (0peak) for piling noise out to a radial distance of 50 km is shown in Figure 8.2. The sound pressure levels decrease with increasing distance from the source, with the highest values being recorded in the immediate vicinity of the piling operation. At 500 m from the source the sound pressure level is above 175 dB (0-peak), this decreases to 155 dB (0-peak) at 5 km and 75 dB (0-peak) at 50 km. The piling sound frequency spectrum at a distance of 10 km is shown in Figure 8.3 and for illustrative purposes the audiogram of a harbour porpoise. The noise would be audible at this level in the absence of ambient noise. To determine the consequences of the received levels on any marine mammals which might experience such noise emissions it is necessary to relate the levels to known or estimated impact thresholds. Southall and his co-workers produced a comprehensive review of the evidence for impacts of underwater noise on marine mammals, and proposed criteria for preventing injury to individuals based on both peak sound levels and Sound Exposure Level (SEL) and also thresholds for pulsed and non-pulsed sounds (Southall et al. 2007). As there are always two choices of impact criterion that can be used (Peak or SEL) for any situation, when applying these criteria, Southall recommends to use the more conservative exposure criteria (i.e. whichever criteria is exceeded first). For whales and dolphins, the criteria set a maximum 0-peak sound pressure level of 230 dB re 1 μPa and a SEL of 198 dB for pulsed sounds, and a maximum SEL of 215 dB for non-pulsed sounds. Data from seals suggest that their auditory system may be affected by lower levels of sound; criteria for them are a maximum of 0-peak pressure level of 218 dB and a maximum SEL of 186 dB for non-pulsed sounds. All criteria in the Sound Pressure Level are based on the peak pressure known or assumed to elicit TTS- onset November 2010
plus 6 dB. Criteria in the Sound Exposure Level are based on the SEL eliciting TTS-onset plus 1) 15 dB for any type of marine mammal exposed to single or multiple pulses or 2) 20 dB for cetaceans or pinnipeds in water exposed to non-pulses. It is expected that piling noise will be above both ambient noise and the audible frequencies of harbour porpoise for at least 25 km. Therefore, it is likely that the zone of audibility (the area where sounds may be heard by marine mammals) extends to at least a 25 km distance from the source. The total area that piling sounds would be likely to be audible to harbour porpoises and seals, and potentially other marine mammals in the area, 2 is at least 1963 km Beyond the area in which injury may occur, it is the effect on marine mammal behaviour (from the series of sequential, or multiple, pile strikes) that will be the most important measure of impact. For example: h Carstensen et al. (2006) report that porpoises showed substantial changes in habitat use during pile driving for the Nysted offshore wind farm in the western Baltic; a number of animals left the area in which construction was occurring. h Thomsen et al. (2006) discuss work by Tougaard et al. from construction of offshore wind farms that noted the acoustic activity of porpoises decreased shortly after piling events and returned to baseline conditions within 3 – 4 hours. Densities of porpoises during driving were significantly lower than before and behavioural observations showed relatively more directional swimming patterns compared to observations obtained on days without construction. These effects were also found at distances up to 15 km from the construction site, although this distance represents the minimum zone of responsiveness as no observations or acoustic logging happened at greater distances. h Bailey et al. (2010) report that noise from pile driving for two wind turbines in the North Sea was detectable above background underwater noise levels for a distance of 70 km and that strong avoidance behaviour could have occurred up to 20 km away. It should be noted that Bailey et al. (2010) report a study of 1.8 m diameter piles that are almost twice as large as those to be used in the Quad204 Project. Pile driving is dominated by low frequencies and since the species most likely to occur in the Quad204 Project area are the toothed cetaceans that are more susceptible to high frequency Page 8.9
Underwater Noise sounds the likelihood of impact on behaviour is somewhat reduced. In addition, a behavioural reaction lasting less than 24 hours and not recurring on subsequent days is not regarded as particularly severe unless it could directly affect survival or reproduction (Southall et al. 2007). Behavioural changes such as moving away from an area for a short period of time, reduced surfacing time, masking of communication signals or echolocation clicks, vocalisation changes and separation of mothers and calves for short periods do not therefore necessarily imply that detrimental effects will result for the animals involved (JNCC, 2010b). The duration of piling operations for the Quad204 Project will be relatively short lived occurring for a few days over a relatively short period time (e.g. days or a small number of weeks) and it is expected that any temporary displacement of animals will be recoverable with redistribution not significantly different from natural distribution. JNCC (2010b) comment that it is unlikely that any single operation producing loud noises for less than 24 hours would result in a disturbance offence.
8.5.3 Seismic noise Seismic surveys are planned to occur once every two years and would be expected to have durations of approximately 30-60 days. The source levels generated from seismic operations will be dependent upon the individual arrays used and the size of individual guns and could potentially generate source levels up to 271dB (peak-peak) and survey across extensive areas of Quad 204. Seismic operations due to the high source levels are thought to be capable of causing impact to marine life, although no studies have yet been able to demonstrate this. BP will conduct Environmental Impact Assessments (EIAs) for every seismic campaign in the West of Shetland area and consider the most applicable mitigation to reduce the risk of causing impact on any marine mammals. The precise details of seismic activities and impact assessments will be described and considered in PON14a applications.
8.5.4
Vessel noise
DP thrusters cannot be disengaged in the presence of sensitive species as they control the positioning of the vessel and disabling this control would introduce unacceptable safety risk. Vessels that utilise DP will be travelling at a relatively slow (or stationary) speed allowing animals time to become accustomed to the vessel (or to move away from it) as it approaches, thereby avoiding Page 8.10
any startle responses. The same will apply to other vessels in transit (e.g. shuttle tankers and supply vessels). It is expected that the use of thrusters will represent an incremental increase to existing noise levels. BP commissioned a desk-based study to specifically assess potential noise sources from the operation of the proposed new FPSO with regards to the impact of noise on cetaceans. This study delivered recommendations on specific design elements of the FPSO that would enable a reduction in noise disturbance to cetaceans: h It was recommended that the technical design of the thrusters be considered, with particular attention given to the verification of noise and frequency levels h It was recommended that an assessment of the noise signature of different combinations of thruster usage be undertaken (e.g. three thrusters at low power or two at high power) Silent thrusters were found to be unavailable in the size required and instead the FPSO will utilise three tunnel thrusters with shrouds to reduce noise emissions and increase thruster efficiency compared to the existing FPSO. Vessel noise impacts have been modelled using a similar approach to that applied for the piling noise. There is little data available on noise source levels from FPSOs in the literature, so for modelling purposes a surrogate noise level has been used which is from a pipelaying vessel measured by MacGillivray and Racca (2006) cited in Wyatt (2008). The overall source SPL for this source is 182.3 dB rms re 1uPa at 1m, and this corresponds to the average of several measurements of oil and chemical tankers taken by Hatch et al. (2008) although this was confined to a range of 71-141 Hz. The same source level has been used for an installation vessel. During installation and for much of the field life there will be an installation or dive support vessel undertaking maintenance, and this source is seen as a good surrogate for this type of vessel. There is also little data on ambient noise in the area that is in a usable form for this assessment; Nedwell (2004) and Swift and Thompson (2000) both report that ambient noise levels are dominated by the vessels present. Nedwell (2004) also reports that measurements taken for pipelay activities near Schiehallion suggested a relatively low noise output for the FPSO compared to other vessels present, although it is not known what state of operation the FPSO was in or whether thrusters were operational.
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Underwater Noise
160-170 150-160 FPSO
Standby vessel
170 DSV/ Installation vessel
160 150
Noise Level dB
Semi-sub Drilling Rig
140-150 130-140 120-130
140 130
110-120
120 110
Shuttle tanker
100
100-110
90
90-100
80 70
80-90 70-80
Figure 8.5: Predicted sound pressure levels re 1µPa for operational noise case, 10 km square grid
Data for a semi-submersible drilling rig has been taken from Hannay, MacGillivray et al. (2004) cited in Wyatt (2008) and, for a standby vessel, measurements from Supplier III given in Brueggeman et al. (1990) have been used, although other sources have given similar noise levels for this type of vessel. In some respects these source levels might be interpreted as being upper bounds on the sources present in that although the operations from which they were taken reflect temporary situations (e.g. use of thrusters on the FPSO, standby vessel
under way rather than stationary, installation/maintenance vessel operating); this makes the composite picture conservative. Long term exposure would be based on a representative mixture of such activities over time, rather than the snapshot illustrated here. The model results for a 10 km square around the FPSO are shown in Figure 8.5. A plot of the noise spectrum at 7.5 km distance is shown in Figure 8.4; this shows one of the source levels (at 1m) as a reference point, and then shows the received noise spectrum at 7.5 km allowing for attenuation,
Noise level dB
180 160
Predicted noise level
140
Source 1
120
Harbour Porpoise
100 80 60 40 20 10
100
1000
10000
100000
1000000
Frequency Hz Figure 8.4: Noise spectrum at 7.5 km during operational noise case
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Page 8.11
Underwater Noise along with a harbour porpoise audiogram. Higher frequencies attenuate more quickly, and it can be seen that at this distance the noise would be inaudible to that species, although it would remain audible to mysticetes in the absence of ambient noise. To consider, at a high level, the potential for cumulative effects in combination with the Foinaven FPSO, an equivalent noise source at Foinaven has been added to the model and a wider scale used to illustrate where the noise zones are additive. This is shown in Figure 8.6. The modelling shows that the noise field over a wide area is influenced by the presence of the FPSO and its operational vessels, and the use of thrusters is the main source of these emissions. The noise from the drilling rig can be seen to have little effect on the noise climate, however its influence will increase during periods when dynamic positioning is used. The rig will be attended by a supply vessel perhaps three times a week and anchor handling tugs every few months, and it is likely that noise from these vessels will be more significant than the rig, as observed by McAuley (2008) around a drilling operation. While these sources could also be modelled, it would not change the overall conclusion about noise impacts in the area, and while it is conceivable that anchor handling operations could equal the noise output from the FPSO and associated vessels, this would be for a short period. It can be concluded that vessel noise is a
significant part of the noise landscape within tens of kilometres of the FPSO and its subsea infrastructure. The noise levels will be similar to commercial shipping, but with the difference that they are maintained in the same location for the life of the field. There is no evidence to suggest these impacts are significant, but it is also the case that some of the source levels, particularly the FPSO, are not well characterised, and the science of predicting sound exposure over time (versus short term threshold levels) is quickly emerging. Predictive noise measurements are only possible to provide indicative estimates of sound levels, therefore targeted noise measurements will be undertaken in order to validate the predictions of the noise emissions made for Quad204 Project activities. From a review of oil and gas sources it has been identified that the FPSO, which is not expected to generate particularly high levels of underwater sound, has not been fully characterised so this is a data gap in BP’s understanding that should be targeted. It would also be worthwhile to better characterise the noise spectrums and sound levels generated by vessels that routinely operate in the Quad204 Project area to improve the accuracy of the noise predictions. Also, there have been relatively few studies which have measured the ambient noise in waters to the west of Shetland, and in order to fully understand and better assess how Quad204 Project activities contribute collectively to sound levels in the area it is important to monitor this aspect. This is especially important considering the anticipated duration of oil and gas activities in this area as
Figure 8.6: Predicted sound pressure levels re 1µPa for operational noise case illustrating additive effects with Foinaven FPSO, 33.5 km square grid
Page 8.12
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Underwater Noise there will be notable influences on the ‘background’ noise for many decades.
h Recording all sightings of marine mammals using JNCC Standard Forms
BP therefore commits to undertaking further noise measurements of the existing Schiehallion FPSO and associated activities with a view to better characterising the emissions, current ambient noise levels and validating the predictive noise modelling assessment made in this ES. Future noise measurements may allow for the opportunity of quantifying the sound exposure of relevant species over time.
h Reporting to the JNCC following the end of the pile driving programme, detailing the marine mammals sighted, methods used to detect them and details of any problems encountered
8.6
Management and mitigation measures
8.6.1
Piling noise
Prevention of injury BP will implement a number of measures to mitigate piling noise impacts based on the principles of the JNCC guidelines for piling activities (JNCC, 2010b). BP will implement the following mitigation measures: h Use of suction anchors will take preference over pile driving. BP will discuss any pile driving operations with the JNCC h Carrying out pile driving for as short a period as possible h Carrying out cetacean monitoring by qualified marine mammal observers (MMO) h Beginning observations 30 minutes before the commencement of any pile driving activities h Delaying the start of the piling operations if cetaceans are detected within 500 metres until those animals have moved away (not sighted for at least 20 minutes) h Building up power slowly (soft-start) over at least 20 minutes to allow adequate time for any cetaceans to move away from the area before full power is reached h If pile driving is paused for a period of greater than ten minutes then the soft start procedure will be re-initiated before full power recommences. The MMO will keep watch throughout the piling operations and where the MMO can confirm the absence of marine mammals from the mitigation zone the soft-start will commence immediately. Where marine mammals are present within the mitigation zone, the re-start of the piling operations will be delayed until marine mammals have moved away (not sighted for at least 20 minutes)
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Prevention of disturbance As noted above, BP will use suction anchors where possible to avoid the need for piling activity. Where driven piling does occur, however, key to limiting the likelihood of disturbance will be the pattern of piling activity. The piling operations will be of relatively short duration, occurring for a few days, over a relatively short period time (e.g. days or a small number of weeks). Piling is not likely to continue for more than an estimated 2 - 3 hours at a time. The noise emitted from piling activity is multi-pulse, in that a number of individual pulses follow sequentially. It is anticipated that the strike frequency of the hammer on pile will reach a maximum of 30 blows per minute, equating to a maximum of one strike every 2 seconds. Marine mammals subject to masking effects are likely to be able to detect other noises present in the marine environment (for example, communication calls from conspecifics or auditory clues to prey presence) between pulses. This would reduce the likelihood of negative impact on activities such as communication, echolocation and predator avoidance. In addition, there will be a period of time between each pile being installed where no hammering will occur; in addition to the requirement to move the pile driving vessel between piles, there is also likely to be a period of up to a few hours between each pile where the next pile in sequence is lifted and aligned and relevant checks are conducted. The breaks between each pile will reduce the period over which noise is experienced as one series of pulses and will reduce the likelihood of behavioural disturbance.
8.6.2
Seismic noise
BP will implement a number of measures to mitigate seismic noise impacts based on the principles of the JNCC guidelines for seismic activities (JNCC, 2010b) to prevent injury and disturbance to marine mammals. BP will implement the following mitigation measures specific to any seismic survey: h Carrying out the survey over as short a time period as possible
Page 8.13
Underwater Noise h Carrying out cetacean monitoring by qualified marine mammal observers (MMO) h Using Passive Acoustic Monitoring (PAM) which increases the detection of certain marine mammal species especially during periods of poor visibility h Beginning observations 30 minutes before the commencement of any seismic activities h The air gun array will be configured to maximize the proportion of the energy that is directed downward and to minimise the horizontal sound propagation h Delaying the start of the seismic survey if cetaceans are detected within 500 metres until those animals have moved away (not sighted for at least 20 minutes) h Building up power slowly (soft-start) over at least 20 minutes to allow adequate time for any cetaceans to move away from the area before full power is reached h If the seismic survey is paused for a period of greater than ten minutes then the soft start procedure will be re-initiated before full power recommences. The MMO will keep watch throughout the seismic operations and where the MMO can confirm the absence of marine mammals from the mitigation zone the soft-start will commence immediately. Where marine mammals are present within the mitigation zone, the re-start of the seismic operations will be delayed until marine mammals have moved away (not sighted for at least 20 minutes)
are likely to attenuate rapidly leaving only the lower frequencies present at greater distances from the sound source. Although low-, mid- and highfrequency cetaceans are likely to occur in the Quad204 Project area, the most frequently sighted cetacean (the odontocete Atlantic white-sided dolphin) is considered to belong to a cetacean group that shows a low sensitivity to low frequency sounds. Although the ranges of a number of cetacean species more susceptible to low frequency sound do include the Quad204 Project area, the area is not known to be of high importance in terms of reproduction or resident populations. The vessel from which pile driving operations will be undertaken will be on-site for a maximum period of days or weeks rather than months or years during which time there is expected to be a maximum of 10 - 60 hours of pile driving activity. The vessel from which seismic surveys will be conducted will be on-site for a maximum period 30 - 60 days during which time the surveys will be conducted with long breaks in activity whilst the vessel turns. Given the short duration and the good swimming capabilities of cetaceans and their nomadic behaviour implies that they will actively avoid loud noise sources, it is unlikely that whales and dolphins will be exposed to sound which would cause damage or disturbance, even if sounds are initiated suddenly in close proximity to the animal.
h Reporting to the JNCC following the end of the seismic operations, detailing the marine mammals sighted, methods used to detect them and details of any problems encountered
Considering that at a distance of 10 metres from the pile driver the sound pressure levels will be below that required for PTS/TTS onset, the absence to a degree of the cetacean species most susceptible to low frequency sounds, the short period of time over which pile driving and seismic noise will be emitted, along with the mitigation measures to be employed, significant, negative, residual impacts occurring as a result of the piling and seismic activities in the Quad204 Project area are considered unlikely.
8.6.3
8.7.2
h Recording all sightings of marine mammals using JNCC Standard Forms
Vessel noise
Recognising the uncertainties in the assessment of impacts of underwater sound generation, BP is committed to contributing to the overall understanding of underwater noise in the West of Shetland region as part of a BP-wide programme for noise data collection as discussed in Section 8.5.4.
8.7
Residual impacts
8.7.1
Piling and seismic noise
Pile driving and seismic surveys are dominated by low frequencies; any high frequencies generated Page 8.14
Vessel noise
Southall et al. (2007) state that for all cetaceans exposed to nonpulses (which includes vessel noise), the recommended criterion for injury is the same as for single pulses. The details of vessel noise given in Section 8.5.4 suggest that this criterion will not be met and it is unlikely that there will be any hearing damage as a result of vessel noise. The project is located on an existing operational site with noise inputs from a variety of vessels, so the change due to the installation and operation of the Quad204 FPSO will be small, and overall, impacts are not considered significant. Vessel November 2010
Underwater Noise noise will, however, continue to dominate the local ambient noise for the life of the field and there remains uncertainty around the source noise characteristics and long-term sound exposure from a largely static noise source. To validate the assumptions in this assessment, further measurement and analysis will be undertaken prior to start-up of the Quad204 FPSO.
8.8
Cumulative and transboundary impacts
8.8.1
Cumulative impacts
Cumulative effects can result from a situation where two or more sound sources are operational at the same time. This could occur if a number of vessels are simultaneously operating using DP (e.g. where two support vessels come together). The potential for impact is reduced as the number of vessels operating will be restricted to those in Chapter 6, the majority of additional vessels will be on-site during the installation phase and the period over which use will occur will be temporally limited. Driven piling will take place over a far shorter time than that presented by the project overall. Cumulative effects may occur with other noise sources in the project (for example, thrusters) but will be limited to the 10 - 60 hours in which the pile driving will occur. Seismic surveys taking place will increase noise levels and vessel activity for a period of 30-60 days every two years, however this is a much shorter time than presented by the project overall. It is possible that noise sources will overlap with other BP developments in the region. For example, the Foinaven FPSO and the Clair Ridge Project (which is likely to be developed over a similar time period to the Quad204 Project). As both fields are located some distance from the development and previous experience of the range over which noise sources such as pile driving may impact upon the behaviour of marine species suggests that there will be no overlap between these developments. Indeed, separate noise modelling conducted by Subacoustech Environmental on behalf of BP as part of the Clair Ridge development suggest that the noise footprint of the piling will, in the cases related to lethal, physical or audiological injury, extend only to a number of metres from the development. The behavioural footprint extends further (tens of kilometres) and thus the possibility for limited cumulative impacts exists. However, the impacts of such changes are considered unlikely to be significant and, as such, negative cumulative impacts are not expected to be significant either.
November 2010
There are also likely to be inputs from other anthropogenic sources that are unrelated to the oil and gas industry including shipping, fishing vessels and military exercises. Operations that are part of the Quad204 Project will add to background noise levels but the nature of the anticipated noise sources, the short duration estimated for pile driving and the fact that the Quad204 Project area is not particularly busy in terms of shipping and fishing suggest that significant cumulative noise effects are unlikely. The recent offshore energy SEA (DECC, 2009c) concluded that an increase in pulse noise generation associated with oil and gas licensing and offshore wind leasing could lead to cumulative effects but that these effects are not yet clearly understood. As such, it is proposed that operational criteria should be established to limit the cumulative pulse noise experienced in key areas of marine mammal sensitivity. Mitigation measures outlined in Section 8.6 will limit the noise emissions from piling and seismic activity and will consequently limit the impact on marine mammals in the area. DECC (2009c) also comment that cumulative acoustic effects are more likely to result from continuous operational noise (presumably including vessel activity) than from pulse noise. Considering that the West of Shetland region is not considered a particularly busy region for shipping and that vessel presence will be restricted to the days outlined in Chapter 6, the additional noise from vessels linked to the Quad204 Project is unlikely to increase the baseline noise signature significantly. Cumulative noise impacts from the closest installation, Foinaven FPSO, are not considered significant.
8.8.2
Transboundary impacts
The Quad204 Project area is approximately 35 km from the UK-Faroe median line and thus it is possible that underwater noise from the project may be detected in Faroese waters. However, the noise modelling concludes that the noise will be at levels sufficiently low to injure only harbour porpoise within approximately 1 m of the piling activity (which will be mitigated for through the marine mammal monitoring zone) and direct transboundary impacts are therefore unlikely. Seismic activity will be at a lower source level than the piling activity and mitigation measures make direct transboundary impacts unlikely. Should cetacean behaviour be affected by any aspect of the Quad204 Project, whether cumulative or from a specific source, it is possible that transboundary effects will occur since Page 8.15
Underwater Noise cetaceans are mobile species in nature, ranging over many hundred or thousands of kilometres (e.g. Atlantic white-sided dolphin, Reid et al. 2003) and their populations and subpopulations are not delimited by human maritime boundaries. Thus, a cetacean that is somehow affected by an activity occurring as part of the Quad204 Project may well cross boundaries into waters of other nations. As noted in Sections 8.5 and 8.7, however, the likelihood of the operations impacting upon cetacean species in the area is negligible and consequently the actual risk of effecting residual transboundary impacts is very low. Phocids (seals) especially are a relatively coastal species and thus transboundary effects are even less likely for this group. DECC (2009c) report that there is the potential for underwater noise on the UKCS to exert transboundary effects. Whilst this same sentiment is noted by DTI (2003) in the SEA for the area in which the Quad204 Project is sited, DTI (2003) conclude that there are no identified transboundary effects in which environmental consequences in a neighbouring state are overwhelmingly due to activities resulting from licensed activity in the region.
8.9
8.9.1
European protected species (EPS) risk assessment Background
As described in Section 8.2, both the HR and OMR describe an offence of which a person would be guilty if he deliberately captured, injured, or killed any wild animal of an EPS or deliberately disturbed wild animals of any such species.
h The duration and frequency of the activity h The intensity and frequency of sound and extent of the area where injury/disturbance thresholds could be exceeded, taking into consideration species-specific sensitivities h The interaction with other concurrent, preceding or subsequent activities in the area (incombination effects) h The Southall et al. (2007) thresholds for injury and behavioural responses, and other relevant published studies h Whether the local abundance or distribution could be significantly affected If the Stage I EPS risk assessment concludes that an offence of either form is still likely, and the applicant determines that there are no other available options or methods, the EPS licence assessment process (a Stage II EPS licence assessment) must be initiated. This comprises three tests which are used to determine the likely consequences of any activity for which an EPS licence is sought. The two-stage EPS licence application process is summarised in Figure 8.7. In accordance with the regulations, and following the methodology outlined by JNCC (2010b), a Stage I EPS risk assessment will be conducted for the relevant activities. The following sections assesses if an EPS licence is required for the piling activity only. As seismic surveys are subject to permitting requirements (through the PON14a application process), an EPS assessment for the seismic survey will be undertaken once the full seismic programme details are known.
BP must assess whether or not the noise emitting operations from the Quad204 Project may cause an injury or disturbance offence to any species designated as an EPS. If this is the case, BP will be required to apply for an EPS licence. The process for determining the likelihood of an offence occurring, and consequently the requirement for an EPS licence is described by JNCC (2010b) and involves a two-stage approach to risk assessment for the offences detailed above. The first step (a Stage I EPS risk assessment) requires an assessment of the likelihood of committing an offence, where alternatives and mitigation measures are taken into account. The Stage I EPS risk assessment will itself consist of two main components: determination of the likelihood of an injury offence and determination of the likelihood of a disturbance offence. This will require a review of:
Page 8.16
November 2010
Underwater Noise
Figure 8.7: The two-stage EPS licence application process (After JNCC, 2010b)
8.9.2 Stage I EPS risk assessment Noise assessment methodology The most recent JNCC guidance regarding assessing the likelihood of noise impacts on cetaceans (JNCC, 2010b) proposes that physical injury, such as a permanent threshold shift in hearing to an EPS would constitute an injury offence. The guidance also proposes that a disturbance offence may occur when there is a risk of animals incurring sustained or chronic disruption of behaviour or when animals are displaced from an area, with subsequent redistribution being significantly different from that occurring due to natural variation. The risk of either offence will be higher in areas where EPS occur frequently and/or in high densities. Conversely, the risk will be negligible in areas where EPS are unlikely to occur, occur irregularly or where the same individuals are unlikely to remain in the same area for long periods of time (JNCC, 2010b), as is considered the case for the Quad204 Project area. Injury offence To assess the possibility of an injury offence resulting from pile driving at the Quad204 Project, it is necessary to consider both the likelihood that the sound will exceed injury thresholds and the likelihood that the sensitive receptors will be exposed to that sound (Figure 8.8).
November 2010
Figure 8.8: Approach to risk assessment for injury (After JNCC, 2010b)
As detailed, certain activities that produce loud sounds in areas where animals of an EPS could be present have the potential to result in an injury offence unless appropriate mitigation measures are implemented. It is important to consider the levels of sounds emitted and the distance from the sound source within which species could be injured. From modelling of the peak sound pressure levels it is only expected that sound levels will be high enough to cause Permanent Threshold Shifts in hearing to cetaceans within the first few metres. These distances are confirmed by analysis of acoustic data collected during Clair Page 8.17
Underwater Noise Phase 1 pile driving activities that suggested that animals would have to be very much closer to the source than 500 m to experience any injury effects (White, 2010). A single piling operation could be one of many sources of noise (anthropogenic and natural) in an area. Within the Quad204 Project, additive effects could occur where two or more sound sources are operational at one time. Piling will occur for a maximum of 21 piles (although the likely number is much lower) and will occur for 10 - 60 hours, a period that represents a very small fraction of the overall project timeframe. Cumulative effects through overlap with other sounds sources (e.g. thrusters) will therefore be limited to the very short period in which the piling is operational. Considering the modelled zones of injury impact and the mitigation measures outlined in Section 8.6.1, no injury offence is expected and there is no requirement to apply for an EPS licence for the injury offence.
(2007) behavioural response severity scale (Table 8.3) could be significant. The more severe the response on the scale, the lower the amount of time that the animals will tolerate it before there could be significant negative effects on life functions, which would constitute disturbance under the relevant regulations.
Response score
Corresponding behaviours in free-ranging subjects
5
Extensive or prolonged changes in locomotion speed, direction, and/or dive profile but no avoidance of sound source Moderate shift in group distribution Change in inter-animal distance and/or group size (aggregation or separation) Prolonged cessation or modification of vocal behaviour (duration > duration of source operation)
6
Minor or moderate individual and/or group avoidance of sound source Brief or minor separation of females and dependent offspring
Disturbance offence
Aggressive behaviour related to noise exposure (e.g., tail/flipper slapping, fluke display, jaw clapping/gnashing teeth, abrupt directed movement, bubble clouds)
To assess the possibility of a disturbance offence resulting pile driving at the Quad204 Project, it is necessary to consider both the likelihood that the sound could cause non-trivial disturbance and the likelihood that the sensitive receptors will be exposed to that sound (Figure 8.9).
Extended cessation or modification of vocal behaviour Visible startle response Brief cessation of reproductive behaviour 7
Extensive or prolonged aggressive behaviour Moderate separation of females and dependent offspring Clear anti-predator response Severe and/or sustained avoidance of sound source Moderate cessation of reproductive behaviour
8
Obvious aversion and/or progressive sensitization Prolonged or significant separation of females and dependent offspring with disruption of acoustic reunion mechanisms Long-term avoidance of area (greater period of time than source operation)
Figure 8.9: Approach to risk assessment for disturbance (After JNCC, 2010b)
Southall et al. (2007) recommended that the only currently feasible way to assess whether a specific sound could cause disturbance is to compare the circumstances of the situation of concern with empirical studies that have carefully controlled variables. The guidance (JNCC, 2010b) suggest that a score of 5 or more on the Southall et al. Page 8.18
Prolonged cessation of reproductive behaviour 9
Outright panic, flight, stampede, attack of conspecifics, or stranding events Avoidance behaviour related to predator detection
Table 8.3: Southall et al. (2007) behavioural disturbance scale (scores 5 and upwards)
November 2010
Underwater Noise Pile driving is a pulsed sound made up of multiple pulses, a noise type which is considered to have negligible effects on marine mammal calls given the discontinuous nature of these sounds (LGL Ltd and JASCO Research, 2005). For example, a review of the literature shows: h Some whales are known to continue calling in the presence of seismic pulses since the vocalisations can be heard between the pulses (e.g. Greene and McLennan 2000, Madsen et al. 2002, Jochens and Biggs 2003) h Some species increase vocalisations during pulsed sounds (Di Iorio and Clark, 2009) h Pile driving could mask strong bottlenose dolphin vocalisations out to a number of kilometres (Jefferson et al. 2009) h Porpoises show substantial changes in habitat use during piling (Carstensen et al. 2006) and decreased acoustic activity after driving events (Tougaard et al. in Thomsen et al. 2006), although this returned to baseline conditions within 3 – 4 hours h Bailey et al. (2010) report strong avoidance behaviour in bottlenose dolphins from pile driving noise There are no clear and consistent behavioural responses by cetaceans to pile driving activity, perhaps unsurprisingly considering the variability in cetacean hearing thresholds and the variables involved in piling (e.g. water depth, pile diameter). Scoring of behavioural effects described here suggests up to a possible 6 (as per Table 8.3). The score of 6 does not mean that all qualifying statements for this score have been met; in the case of the examples described above, the avoidance of the sound source for the period during which the noise will be emitted is the only reason a score of 6 is assigned. Southall et al. (2007) note that it is the repeated or sustained disruption of behaviours such as feeding or communication that is likely to have a significant effect on vital rates (e.g. reproductive capacity, life expectancy) and not just brief responses to the factor of disturbance. A behavioural reaction that lasts for a short period of time and does not recur on numerous occasions (as is the case for the Quad204 Project pile driving) is consequently not considered to be particularly severe as it is unlikely to directly affect survival or reproduction. Behavioural changes such as moving away from an area for a short period of time, reduced surfacing time, masking of communication signals, do not therefore necessarily imply that this will result in detrimental effects on the animals involved (JNCC, 2010b). The likely disturbance November 2010
impact with respect to the key influencing factors (as described by JNCC, 2010b) is as follows: h Duration h For most cetacean populations in UK waters disturbance is unlikely to result from single, short-term operations (e.g. the driving of a small number of small diameter piles). Such activities would most likely result in temporary sporadic disturbance which would not be likely to impair the ability of an animal to survive and reproduce to the extent that there would be significant effects on the local abundance or distribution. The piling operations at the Quad204 Project will be short-term in nature (maximum of 10 - 60 hours) so the likelihood of a disturbance offence being committed is substantially reduced. JNCC (2010b) comment that it is unlikely that any single operation producing loud noises for less than 24 hours would result in a disturbance offence. h Pattern of piling h The strike frequency of the hammer on pile will equate to one strike every two seconds. Marine mammals will be able to detect other noises present in the marine environment between pulses (for example, communication calls from conspecifics or auditory clues to prey presence), reducing the likelihood of negative impact. There is likely to be a number of hours between each pile being hammered which will reduce the period over which noise is experienced as one series of pulses and will reduce the likelihood of behavioural disturbance. The actual noise output from the piling is likely to be an intermittent series of pulses occurring for approximately 10 - 60 hours which, considering available evidence and guidance, does not represent a high disturbance risk. h Cumulative effects h Although a single act may fall below the threshold of the offence a repetition of the same act for long periods of time may result in the threshold being reached. For example, an operation that lasts for less than 24 hours but is recurrent on subsequent days for several weeks to months could have a higher potential for a disturbance offence than an operation that emits loud noises continuously for 24 hours. Piling for the Quad204 Project will not occur for more than 10 - 60 hours and thus, in the context of continuous repetition over weeks Page 8.19
Underwater Noise or months, is unlikely to pose any significant threat of disturbance. As there are no known resident groups with site fidelity and the general abundance of animals is not high (Chapter 4) and the limited effects will be intermittent and short-lived, the likelihood of exposing an EPS to non-trivial disturbance is low and the risk of an offence negligible.
8.9.3
Stage I EPS risk assessment conclusion
Considering that the zones of possible injury are very restricted or non-existent (depending on the species), that the most commonly sighted species are considered less susceptible to low frequency sounds, that pile driving noise will be emitted over a short period of time and that BP intend to deploy a suite of mitigation measures that will eliminate any potential for injury and severely limit the risk of non-trivial disturbance, significant, negative, residual injury or disturbance impacts occurring as a result of the piling activities associated with the Quad204 Project are considered unlikely. Providing that the mitigation measures for piling are applied there will thus be a negligible risk of injury or disturbance offence and BP considers that an application for an EPS licence is not required.
Page 8.20
November 2010
Atmospheric Emissions
9
Atmospheric Emissions
The use of energy optimisation and BAT studies for power generation, and key design decisions regarding flaring, have minimised the atmospheric emissions associated with the project. This chapter details the expected residual levels of emissions from the Quad204 Project, and models the dispersion of emissions from the major operational sources, i.e. the power generation turbines and safety-related flaring.
9.1
Introduction
Atmospheric emissions, with concomitant impacts on natural ecosystems and human well-being may cause effects at local and regional levels (mainly the environs of Shetland for Quad204), on transboundary (Norway and Faroe) and on global scales. Local and transboundary issues include the generation of acid rain from oxides of nitrogen (NOX) and sulphur (SOX) released from combustion, and the human health effects of ground level nitrogen dioxide (NO2), sulphur dioxide (SO2) (released from combustion), and ozone (generated via sunlight action on NOX and volatile organic compounds (VOCs). Note that due to the dispersive nature of the environment and the lack of receptors in the vicinity of the Quad204 Project, local elevated concentrations of emissions will be short lived and are unlikely to be detectable except in the vicinity of the activities. Concern with regard to atmospheric emissions is increasingly focused on global warming and climate change. The Intergovernmental Panel on Climate Change (IPCC) in its fourth assessment report states that “Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic GHG concentrations.” Although BP recognises that “uncertainties persist about not only the magnitude and timing of temperature increases but also the consequences”, the company has made a corporate commitment to seek solutions to climate change, including reduction in greenhouse gas emissions and continuous improvement in its overall use of energy. This will partly be achieved by designing projects to be more energy efficient over their operational life. The environmental effects of the most common November 2010
combustion gases, which can be split into direct and indirect greenhouse gases, are summarised in Table 9.1. Direct greenhouse gases have an effect on radiative forcing within the atmosphere while, through atmospheric chemistry, indirect greenhouse gases impact upon the abundance of the direct greenhouse gases, thereby increasing the overall greenhouse effect. Gaseous emission
Environmental effect
Direct greenhouse gas Carbon dioxide (CO2) Methane (CH4) Nitrous oxide (N2O)
Inhibits the radiation of heat into space affecting temperatures at the Earth’s surface. May contribute to climate change.
Indirect greenhouse gas Carbon monoxide (CO)
May contribute indirectly to climate change.
Indirect greenhouse gas Oxides of nitrogen (NOx)
Acts as a precursor to low-level ozone formation. Contributes to acid deposition (wet and dry) which impacts both freshwater and terrestrial ecosystems.
Indirect greenhouse gas Volatile organic compounds (VOC) include non-methane hydrocarbons (NMHC) and oxygenated NMHC (e.g. alcohols, aldehydes and organic acids)
Influence climate through their production of organic aerosols and their involvement in photochemistry, i.e. production of ozone (O3) in the presence of NOx and light.
Indirect greenhouse gas Sulphur dioxide (SO2)
Contributes to acid deposition (wet and dry) which impacts both freshwater and terrestrial ecosystems.
Particulate matter (PM)
Dependent upon composition.
Table 9.1: Environmental effects of atmospheric emissions
During the ENVID process (see Section 5.4), CO2 emissions from power generation and from safetyrelated flaring were identified as being potentially significant. The mitigation measures and residual emissions are discussed below. All potential sources of atmospheric emissions associated with the Quad204 Project have been assessed and these fall into two broad categories: Emissions arising from project activities, including: h FPSO main power generation system (using both fuel gas and diesel) h Combustion of hydrocarbon gases via the flare system h Venting (particularly from cargo off-loading) h Emissions from vessel operations, including drilling rig, shuttle tanker and support vessels Page 9.1
Atmospheric Emissions
9.2
Regulatory control
h Council Directive (2003/87/EC) concerning the establishment of a scheme for greenhouse gas emission allowance trading, known as The EU Emissions Trading Scheme (EU ETS) Directive, is implemented within the offshore oil and gas industry through The Greenhouse Gas Emissions Trading Scheme Regulations 2005 (as amended). The Regulations require that any installation with combustion plant (gas turbines, diesel engines etc.) that on its own or in aggregate with any other combustion plant having a rated thermal input exceeding 20 MWth (th refers to thermal input) is registered under the EU ETS. A registered installation will be issued with an EU ETS permit, which will have conditions placing an obligation on the operator to submit a detailed monitoring and reporting plan. Currently within the offshore oil and gas industry, the EU ETS only covers reporting of CO2 emissions from power generation and flaring. As the Quad204 Project will have combustion plant exceeding 20 MW (th) it will be captured within these regulations. Potential future changes The next phase of EU ETS (Phase III) starts in 2013 and benchmarking is ongoing. Any CO2 generated from electricity generation will not qualify for an allowance. BP will hold early discussions with DECC to ascertain access to the New Entrants Reserve (NER). There is also the potential for future inclusion of venting and CH4 and non-methane hydrocarbons (NMHC, also known as VOCs) in the EU ETS, as these are included in the basket of gases under the Kyoto protocol. VOCs have a much greater greenhouse gas (GHG) potential than CO2. h Council Directive (96/61/EC) concerning “Integrated Pollution Prevention and Control” (known as the IPPC Directive) is implemented within the UK offshore oil and gas industry through the Offshore Combustion Installations (Prevention and Control of Pollution) Regulations 2001 (as amended). The system of IPPC applies a comprehensive approach to the environmental regulation of combustion processes to generate power on offshore facilities. The integrated approach means that emissions to air, the sea and land, plus a range of other environmental effects, must be considered together and that DECC must set permit conditions to achieve an overall high Page 9.2
level of protection for the environment. The approach and permit conditions are based on the use of Best Available Technique (BAT), which balances the costs to the operator against the benefits to the environment. IPPC aims to prevent emissions and waste production and, where that is not practicable, to reduce them to acceptable levels. h Current legislation governing flaring from offshore operations, implemented by DECC, is the Energy Act 1976 and the Petroleum (Production) (Seaward Areas) Regulations 1988. Consent is required for flaring, venting or reinjection of gas unless permitted under specific terms of the production licence. Consent terms restrict gas disposal volumes but no statutory limits are set. Where a facility is flaring in excess of 50 tonnes per day, the flare level will be reviewed and consent issued annually. DECC has an objective to reduce non-safety related flaring by 5% per year. Reductions in flaring are achieved through close cooperation between DECC and the operators, rather than prescriptive limits. h Under the Energy Act 1976, consents to vent are required for all Category 4 (unignited vents) including venting of gases from onboard crude oil storage tanks. Where a field is venting > 5 tonnes per day the vent level will be reviewed and a vent consent issued annually. This level of vent is considered to represent a potential opportunity for further reduction in levels. These applications will need full supporting details with medium and long term plans for reduction of venting. h The Environmental Emissions Monitoring System (EEMS) is designed to enable the analysis of offshore oil and gas industry environmental data. EEMS provides the vehicle for offshore oil and gas industry emissions to be incorporated into UK Inventories of atmospheric emissions. The dataset acts as the primary data storage and reporting resource for both UK Government and the offshore industry. EEMS now also includes a number of statutory reporting requirements, in particular, reporting requirements under the PPC Regulations.
November 2010
Atmospheric Emissions
Year
Duration (days)
Total fuel use (tonnes)
CO2 (tonnes)
CO (tonnes)
NOx (tonnes)
N2O (tonnes)
SO2 (tonnes)
CH4 (tonnes)
VOC (NMHC) (tonnes)
CO2e (tonnes)
2013
905
7,737
24,758
62
456
2
31
2
19
43,693
2014
1,611
19,942
63,815
160
1,177
4
80
5
48
112,621
2015
1,541
19,567
62,614
157
1,154
4
78
5
47
110,501
2016
1,631
19,866
63,570
159
1,172
4
79
5
48
112,187
2017
1,511
19,646
62,866
157
1,159
4
79
5
47
110,946
2018
1,540
17,427
55,766
139
1,028
4
70
5
42
98,416
2019
1,130
13,655
43,696
109
806
3
55
4
33
77,114
2020
1,485
17,853
57,130
143
1,053
4
71
5
43
100,822
2021
711
6,749
21,596
54
398
1
27
2
16
38,112
Total
12,065
142,441
455,812
1,140
8,404
31
570
38
342
804,414
Table 9.2: Estimated drilling rig and vessel atmospheric emissions
9.3.1
Drilling and vessel operations
Generation of power onboard the drilling rig during the proposed drilling activities will result in the emission of various combustion gases. Figure 9.1 presents the drilling rig CO2 emissions during Phase 1 of the infill drilling campaign which is expected to commence in 2014 and finish in 2021. A large proportion of the Quad204 Project emissions will be generated by the drilling activities with emissions peaking in 2015, 2016 and 2017, when potentially two drilling rigs will be required and 5, 3 and 4 wells will be drilled respectively.
12
Based on Table 6.3 Estimated vessel types and number of days each will spend on site during Quad204 Project activities
November 2010
30,000 25,000 20,000 15,000 10,000 5,000 2021
2020
2019
2018
2017
2016
0 2015
Sources of potential impact (emissions quantification)
35,000
2014
9.3
40,000
CO2 (tonnes)
h The Merchant Shipping (Prevention of Air Pollution from Ships) Regulations 2008 implement MARPOL Annex VI in the UK and establish controls on marine engines and marine fuel in order to limit emissions, in particular NOx and sulphur oxides (SOx). The Quad204 Project will require various installation and support vessels during it’s lifetime and all vessels will need to have the appropriate UK Air Pollution Certificate (UKAPP) or International Air Pollution Certificate (IAPP) in place as required.
12
Year
Figure 9.1: Estimated drilling rig CO2 emissions
Table 6.3 summarises the number and type of vessel present in the field between 2013 and 2021. Table 9.2 summarises the estimated emissions from the drilling rig(s) and from installation and commissioning vessels based on this information. Best estimates have been used at this stage where the project is still in an early engineering phase in order to enable quantification of vessel emissions. The number of vessels and their duration in the field are subject to change. Durations include allowances for weather related delays. Emissions factors and data sources are provided in Appendix G. Emissions from vessels will peak in 2014. The largest proportion of emissions in 2014 can be attributed to the skip and ship vessel for removal of Page 9.3
Atmospheric Emissions OBM cuttings for onshore processing (19%) (Figure 9.2). The Quad204 Project is looking at possible offshore treatment of OBM contaminated cuttings (see Section 2.5), and if this option is taken forward, this will result in a significant reduction in vessel atmospheric emissions as the skip and ship vessel will not be required. This reduction will be partially offset by the additional power generation requirements on the drilling rig needed for the offshore treatment process.
1% 6% 3%
offloaded every 3 weeks after this initial 5 year period.
9.3.2
Well testing will not be undertaken at the drilling rig. Fluids will be directed back to the FPSO test separator thereby eliminating the requirement to flare.
9.3.3
6% 2%
A turbine generator set will be provided on the FPSO to supply all topsides main power requirements. The set will consist of four high efficiency dual fuel turbines. Waste heat from the turbines will be recovered via WHRUs to provide process heating requirements (Section 3.6.9).
13% 19%
Power generation
The Quad204 FPSO will be self-sufficient in power generation and will supply power to a range of production operations such as separation, oil export and gas compression, as well as the utilities and life-support systems.
14% 5%
16%
Well testing
14% 1%
Reel pipelay vessel Pipelay support vessel Anchor handling vessel Standby vessel Survey vessel Skip and ship vessel Tug Construction vessel Inspection repair and maintenance vessel Seismic vessel Shuttle tanker
The estimated FPSO yearly peak electrical load is shown in Figure 9.3. The maximum peak electrical load is estimated at approximately 95.2 MW in 2019 when gas compression requirements are at their peak. Power requirements remain high until 2030, before a significant decline in 2031 in line with a decrease in production.
Figure 9.2: Peak year (2014) CO2 emissions by vessel activity
100 80 60 40 20 2035
2034
2033
2032
2031
2030
2029
2028
2027
2026
2025
2024
2023
2022
2021
2020
2019
2018
2017
2016
2015
0 2014
Electrical load (MW)
Currently, oil is exported via a dedicated shuttle tanker, the Loch Rannoch, to Sullom Voe Terminal. The frequency of round trips is a function of the oil production rate and is currently once every four to five days. It is expected, during the first five years of production, that 111,465 m3 (700,000 bbls) will be offloaded every week by shuttle tanker, and that the same quantity will be
Year Figure 9.3: Estimated peak electrical loads
Page 9.4
November 2010
Atmospheric Emissions Figure 9.4 presents the electrical load breakdown (base year 2016) for the main power users on the FPSO. The HP gas compressors and the water injection system account for 45% and 20% of the total electrical load respectively. 1.0% 5.5%
14.0% 1.5%
Diesel power engines Not all the equipment on the FPSO will be powered by the turbines; some equipment will be diesel-powered and used periodically. These are identified as: h Three firewater pumps
11.0%
h Two key service generators h Two emergency start-up air compressors
2.0%
h One emergency generator
45.0%
20.0%
h Two inert gas generators
HP compressors Water injection PWRI Seawater lift LP compressor Thrusters Cargo and ballast pumps Miscellaneous Figure 9.4: Electrical load breakdown (base year 2016)
Figure 9.5 shows the CO2 emissions from fuel gas and diesel consumption for power generation over the life of the project. In 2025, energy requirements and subsequently CO2 emissions decline by approximately 100,000 tonnes.
400,000
CO2 (tonnes)
300,000
200,000
100,000
2035
2034
2033
2032
2031
2030
2029
2028
2027
2026
2025
2024
2023
2022
2021
2020
2019
2018
2017
2016
2015
0
Year Turbines (fuel gas)
Turbines (diesel)
Miscellaneous diesel
Miscellaneous diesel accounts for diesel consumption due to equipment test runs and shutdowns. Figure 9.5: CO2 emissions breakdown (fuel gas and diesel)
November 2010
Page 9.5
Atmospheric Emissions Table 9.3 summarises the forecast CO2, NOX, SOX, CO, CH4 and VOC emissions from the turbines running on fuel gas between the years 2015 and 2035. CO2 equivalent has been calculated in order to demonstrate the total global warming potential a given type or amount of greenhouse gas may cause, using the functionally equivalent amount or concentration of CO2 as the
reference. Total CO2e atmospheric emissions will be at their highest between the years 2015 and 2024 when oil and gas production is at its highest. In line with a decline in production, atmospheric emissions from fuel gas consumption for turbines will reduce by approximately 100,000 tonnes CO2e in 2025, and will remain at a lower level through to 2035.
Turbine fuel gas use
CO2
NOx
CO
CH4
VOC (NMHC)
SO2
CO2e
tonnes
tonnes
tonnes
tonnes
tonnes
tonnes
tonnes
tonnes
2015
93,297
253,945
1,284
280
86
3.4
18.1
307,823
2016
133,071
362,203
1,741
399
122
4.8
25.7
435,453
2017
133,759
364,077
1,759
401
123
4.8
25.9
438,068
2018
133,658
363,802
1,756
401
123
4.8
25.9
437,683
2019
133,759
364,077
1,759
401
123
4.8
25.9
438,068
2020
133,921
364,518
1,763
402
123
4.8
25.9
438,684
2021
134,063
364,904
1,767
402
123
4.8
25.9
439,223
2022
133,354
362,975
1,748
400
123
4.8
25.8
436,529
2023
133,617
363,691
1,755
401
123
4.8
25.9
437,529
2024
134,205
365,290
1,771
403
123
4.8
26.0
439,762
2025
96,578
262,874
1,375
290
89
3.5
18.7
320,516
2026
96,963
263,922
1,386
291
89
3.5
18.8
322,013
2027
95,889
261,000
1,356
288
88
3.5
18.6
317,842
2028
96,234
261,937
1,366
289
89
3.5
18.6
319,178
2029
95,991
261,276
1,359
288
88
3.5
18.6
318,235
2030
95,667
260,394
1,350
287
88
3.4
18.5
316,978
2031
95,889
261,000
1,356
288
88
3.5
18.6
317,842
2032
95,646
260,339
1,349
287
88
3.4
18.5
316,899
2033
95,829
260,835
1,354
287
88
3.4
18.5
317,606
2034
96,072
261,496
1,361
288
88
3.5
18.6
318,549
2035
95,849
260,890
1,355
288
88
3.5
18.5
317,685
Total
2,353,312
6,405,445
32,070
7,060
2,165
84.7
455.3
7,752,165
Year
Table 9.3: Forecast atmospheric emissions from fuel gas consumption in turbines
Page 9.6
November 2010
Atmospheric Emissions Table 9.4 summarises the forecast total CO2, NOX, SOX, CO, CH4 and VOC emissions from diesel use in the turbines and the equipment listed above between the years 2015 and 2035. Further details on assumptions for these calculations are available in Appendix G.
Year
Total CO2e atmospheric emissions will be at their highest between 2015 and 2024 when oil and gas production is at its highest. In line with a decline in production, total CO2e emitted to atmosphere will decline in 2025 by approximately 2,000 tonnes and will remain at the same lower rate until 2035.
Total diesel use
CO2
NOx
CO
CH4
VOC
SO2
CO2e
tonnes
Tonnes
tonnes
tonnes
tonnes
tonnes
Tonnes
tonnes
2015
3,430
10,951
117
23
0.3
3.4
6.9
15,687
2016
4,326
13,810
134
25
0.3
3.7
8.7
19,211
2017
4,324
13,803
132
24
0.3
3.6
8.7
19,157
2018
4,322
13,797
132
24
0.3
3.6
8.7
19,149
2019
4,324
13,803
132
24
0.3
3.6
8.7
19,157
2020
4,345
13,870
134
25
0.3
3.7
8.7
19,285
2021
4,331
13,822
133
24
0.3
3.6
8.7
19,180
2022
4,315
13,774
132
24
0.3
3.6
8.6
19,122
2023
4,321
13,794
132
24
0.3
3.6
8.6
19,146
2024
4,351
13,889
134
25
0.3
3.7
8.7
19,308
2025
3,503
11,181
118
24
0.3
3.4
7.0
15,966
2026
3,511
11,210
118
24
0.3
3.4
7.0
16,001
2027
3,487
11,133
118
23
0.3
3.4
7.0
15,908
2028
3,515
11,222
120
24
0.3
3.4
7.0
16,063
2029
3,490
11,139
118
23
0.3
3.4
7.0
15,916
2030
3,483
11,117
118
23
0.3
3.4
7.0
15,888
2031
3,488
11,133
118
23
0.3
3.4
7.0
15,908
2032
3,502
11,181
119
24
0.3
3.4
7.0
16,012
2033
3,486
11,130
118
23
0.3
3.4
7.0
15,904
2034
3,492
11,146
118
23
0.3
3.4
7.0
15,923
2035
3,487
11,130
118
23
0.3
3.4
7.0
15,904
TOTALS
80,833
258,036
2,615
502
6.9
73.2
161.8
363,797
Table 9.4: Forecast atmospheric emissions from diesel use in turbines and diesel engines
November 2010
Page 9.7
Atmospheric Emissions
CH4 and VOC (tonnes)
2,500 2,000
Production and storage Cargo offtake
1,500
Cargo transit 1,000 500
2035
2034
2033
2032
2031
2030
2029
2028
2027
2026
2025
2024
2023
2022
2021
2020
2019
2018
2017
2016
2015
2014
2013
2012
2011
2010
0
Year
Figure 9.6: CH4 and VOC emissions comparison between Schiehallion FPSO (2010-2014) and Quad204 FPSO (2015-2035)
9.3.4
Flaring
The new Quad204 FPSO will be fitted with a full flare gas recovery system which will ensure purge flows, leaks, evolved gas in the closed drains system and vents from atmospheric tanks during normal operating conditions are routed back into the process. At a normal flow rate it is estimated that 84,951 m3/day (3 mmscf/d) of gas will be received by the flare gas recovery system from LP flare flow and 14,159 m3/day (0.5 mmscf/d) from the HP flare flow to the LP compressor. Flaring of gas during normal operating conditions is therefore not expected. There will however be a number of scenarios where flaring is required during non-routine operations: h Controlled shutdowns h Emergency conditions h Pressure relief events Based on the flaring scenarios above it is estimated that a total of 725 tonnes of CO2 will be emitted to atmosphere per year, or 18,118 tonnes of CO2 over a 25 year period. The flare gas recovery system on the Quad204 FPSO offers an enormous reduction in the quantity of CO2 emitted to atmosphere compared to the Schiehallion FPSO. The main source of flaring emissions on the existing Schiehallion FPSO is high pressure (HP) flaring used for emergency blowdown (depressurisation), over-pressure relief protection, transient flaring (e.g. start-up or slugging) and November 2010
operational flaring e.g. on compressor shutdowns. The low pressure (LP) system performs a similar function, but releases are very small. Major steps were introduced to reduce flaring emissions from the Schiehallion FPSO in 2003, including improving production operations and gas injection. A major contributor to flaring on Schiehallion was related to production trips caused by process upsets and shutdowns.
9.3.5
Venting
There are two potentially major sources of vented hydrocarbons (CH4 and NMHC) from the Quad204 Project and these are: h Production and tank venting from storage of crude h Cargo transfer operations to the shuttle tanker Production and tank venting and cargo transfer operations were identified as the most significant contributors to CH4 and VOC emissions from Schiehallion. Figure 9.6 shows that with a recovery system available, a large reduction in CH4 and VOCs emitted to atmosphere is achievable during production and storage of produced fluids when compared to the high emission rates on the Schiehallion FPSO where no such recovery system is used. The benefits associated with a VOC recovery system are significant, with a 1,342 tonnes reduction in CH4 and VOC emissions between 2013 and 2016 from production and storage, and a 393 tonnes reduction in emission of CH4 and VOCs during cargo off-take. CH4 and VOCs generated during the offloading process from Quad204 will be recovered onboard Page 9.8
Atmospheric Emissions the shuttle tanker before the gas is vented to atmosphere. Any remaining VOCs and methane will be used for fuel on the shuttle tanker (see Section 3.6.6).
9.3.6
Fugitives
Table 9.5 shows forecast total CH4 and VOC fugitive emissions based upon the number of connection/flange components, valves, pressure release valves and other potential sources for leaks to atmosphere on the new FPSO. The number of connections and flanges on the new FPSO have been minimised in order to reduce the potential for CH4 and VOC fugitive emissions. Component
EEMS emissions factors (kg/year per component)
Number of components
Connections/ flanges
0.946
820
0.8
Valves
4.52
830
3.8
Pressure release valves
8.94
60
0.5
Other
60.9
10
0.6
Total
Total CH4 and VOC fugitive emissions (tonnes/ year)
5.7
Table 9.5: Estimated fugitive CH4 and VOC emissions
9.4
Management and mitigation
Non-FPSO vessel activities All vessels employed during drilling and installation activities will comply with the Merchant Shipping (Prevention of Air Pollution from Ships) Regulations 2008, which will reduce the levels of pollutants entering the atmosphere. Furthermore, all combustion equipment will be subject to regular monitoring and inspections to ensure an effective maintenance regime is in place, ensuring all combustion equipment runs as efficiently as possible. Power generation Considerable effort has been invested in ensuring that power generation onboard the FPSO is as efficient as possible. BP environmental management requirements include a specific focus on improving energy efficiency and measures to protect local air quality. Energy efficiency and minimisation of atmospheric emissions has been November 2010
evaluated as part of the decision making process when assessing options for the main energy consumption items e.g. power generation, gas compression, artificial lift, water injection and oil export. Fuel use will therefore be minimised throughout design and subsequent operation. Emissions from exhaust stacks and metering of fuel gas and diesel fuel rates will be available for each individual turbine and waste heat recovery is provided on all four power generators. Energy metering systems will be installed and maintained and an energy monitoring and reporting system will be provided. Mitigation measures have been undertaken via the following studies in order to minimise atmospheric emissions from the project. h A power generation BAT study h Quad204 energy and emissions forecast Flaring The Project philosophy is for no routine flaring during normal operations. A full flare gas recovery system on the FPSO will remove all routine flaring including purge flow, pilots or leaks, maximise production potential and reduce the environmental impact if the gas were otherwise flared. This system will be subject to specific protective systems and maintenance routines to ensure that they operate at the required level. Emergency blowdown will be minimised as a safety mitigation measure and blowdown will only occur on confirmed fire and gas detection and not during process or compressor shutdowns. Well testing will not be undertaken at the drilling rig. Testing of producer wells will be undertaken by directing fluids back to the FPSO test separator. Venting BP will eliminate all continuous venting as part of the base case in project design. The Quad204 Project will follow recognised design guidelines and incorporate mitigation measures to minimise fugitive emissions of volatile organic compounds. Such measures include but are not limited to: h Low loss fittings h High integrity compressor and pump seals for high pressure systems h Recovery of routing off-gas, system leakage, purge and flash gas by provision of a reliable vapour recovery unit h Provision of a closed drainage system for the hydrocarbon systems Page 9.9
Atmospheric Emissions h Compression of cargo tank vapours and vented vapour returned to the produced gas system h Installation of inert gas system (two IGG units) to provide a secondary source of tank blanketing gas when hydrocarbon gas blanketing is unavailable.
No
Scenario
Requirements
1
Turbine (fuelled by gas) operating under normal condition
GT1, GT2, GT3
2
Turbine (fuelled by diesel at base load) operating under normal condition
GT1, GT2, GT3, GT4
3
Turbine (fuelled by diesel at base load) operating under normal condition
GT1, GT2, GT3
4
Turbine (fuelled by diesel at base load) operating under worst-case condition
GT1, GT2, GT3, GT4
5
Turbine (fuelled by diesel to 20 MWe) operating under normal condition
GT1, GT2, GT3
6
Turbine (fuelled by diesel to 20 MWe) operating under worst-case condition
GT1, GT2, GT3, GT4
7
Flaring
Flare stack
Ozone depleting substances No ozone depleting substances will be used except hermetically sealed domestic-type appliances (e.g. refrigerators) with an inventory <3kg. Refrigeration systems containing CFC or HCFC gases will not be used and refrigerant inventories with least environmental impact will be selected (with reduced ozone depletion potential taking priority over reduced global warming potential). Halocarbon inventories and losses will be recorded annually according to BP Group Reporting Guidelines. Contractors with appropriate licences will be used to maintain equipment containing halocarbons to minimise leaks to the environment.
9.5
Residual impacts
9.5.1
Dispersion modelling
Dispersion modelling was undertaken using ADMS4 to identify whether emissions associated with the new FPSO will have a significant impact on ambient air quality. Dispersion modelling was carried out for emissions of carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxides (NOX), sulphur dioxides (SO2), methane (CH4) and volatile organic compounds (VOCs).
Table 9.6: Modelled scenarios
The environmental quality standards (EQSs) for NO2, SO2 and CO are summarised in Table 9.7. The EQSs are set for the protection of human health and are based on UK Air Quality Objectives (Air Quality Standard (Scotland) Regulations 2007).
Pollutant
Limit Value
NOX (as NO2)
200µg/m
40µg/m SO2
A range of scenarios (Table 9.6) were modelled to assess the predicted impacts from different turbine configurations. Turbines that will be used to generate power on the new FPSO will be fuelled predominantly by fuel gas, although the ability to switch to diesel exists. It is unlikely that all four turbines will be operating together. Flaring was modelled as a stand alone operation as it may occur only during start-up, during maintenance or during an emergency. Concentrations of NOX, SO2 and CO were calculated for comparison with the appropriate air quality objectives. There are no air quality standards for CO2, CH4 or VOC.
Page 9.10
CO
Reference Period and allowed exceedences 3
3
Hourly mean not to be exceeded more than 18 times a year (modelled as th 99.79 percentile) Annual mean
350µg/m
3
1 hour average (not to be exceeded more than 24 times a year, assumed rd equivalent to a 99.73 percentile)
125µg/m
3
24 hour average ( not to be exceeded more than 3 times per year, assumed th equivalent to a 99.18 percentile)
266µg/m
3
15 minute average (not to be exceeded more than 35 times per year, assumed th equivalent to a 99.9 percentile)
3
Running 8-hour mean
10mg/m
Table 9.7: Air quality objectives
The cumulative effects of both the Quad204 and Foinaven FPSO facilities have been modelled together. The worst-case scenario has been considered, assuming that all sources will be working at the same time, although this is an unlikely scenario.
November 2010
Atmospheric Emissions Table 9.8 and Table 9.9 show the maximum predicted concentration of NOX from Quad204 and Foinaven FPSO (the nearest receptor) during normal and abnormal operations.
Objective
Measured as
Objective values/ limit (NO2) 3 (µg/m )
Background
Total NO2 3 (µg/m )
Emission %
Emission % below limit
Emission % above limit
Long-Term AQO (Turbines)
99.79th percentile of hourly averages
200
-
0.4
0.2
100
-
Long-Term AQO (Turbines)
Annual average
40
-
0.004
0.01
100
-
Long-Term AQO (Flare)
99.79th percentile of hourly averages
200
-
22.3
11.15
100
-
Long-Term AQO (Flare)
Annual average
40
-
0.378
0.945
100
-
Table 9.8: Maximum predicted concentration and percentage concentration of NO2 (µg/m3) at the Output Grid (Quad204)
Objective
Measured as
Objective values/ limit (NO2) 3 (µg/m )
Background
Total NO2 3 (µg/m )
Emission %
Emission % below limit
Emission % above limit
Long-term AQO (turbines)
99.79th percentile of hourly averages
200
-
1.00E-03
5.02E-04
100
-
Long-term AQO (turbines)
Annual average
40
-
1.10E-05
2.80E-05
100
-
Long-Term AQO (Flare)
99.79th percentile of hourly averages
200
-
5.44E-05
2.72E-05
100
-
Long-Term AQO (Flare)
Annual average
40
-
7.85E-07
1.96E-06
100
-
Table 9.9: Maximum predicted concentration and percentage concentration of NO2 (µg/m3) at Foinaven FPSO
November 2010
Page 9.11
Atmospheric Emissions
Contour plots of the annual average concentration and the predicted 99.79th percentile of hourly averages for NOX (as NO2) are presented in Figure 9.7 and Figure 9.8. The predicted worst case concentrations (0.004 µg/m3) for normal operation scenario 1 (3 turbines running on gas fuel) may occur up to 2.5 km from the Quad204 FPSO for NOX (as NO2). Concentrations at the Foinaven FPSO, the closest structure to the Quad204 FPSO and located 12.3 km, will be negligible.
Contour plots for the annual average concentration and the predicted 99.79th percentile of hourly averages for NOX (as NO2) to flare are presented in Figure 9.9 and Figure 9.10. Concentrations at the Foinaven FPSO, the closest structure to the Quad204 FPSO will be zero.
10000 AQS (40ug/m3)
0.0014 5000
Metres
0.0012
0.001 0 0.0008
0.0006 -5000 0.0004
0.0002 -10000
-10000
-5000
0
5000
10000
Metres
Figure 9.9: Concentration of flare to annual average of the output grid (NOX as NO2) µg/m3 Figure 9.7: Concentration of normal operation scenario 1 to annual average of the output grid (NOX as NO2) µg/m3 10000 AQS (200ug/m3)
0.16 5000 0.14
Metres
0.12
0.1
0
0.08
0.06 -5000 0.04
0.02 -10000
-10000
-5000
0
5000
10000
Metres
Figure 9.10: Concentration of flare to 99.79th percentile of the output grid (NOX as NO2) µg/m3
Figure 9.8: Concentration of normal operation 1 to 99.79th percentile of the output grid (NOX as NO2) µg/m3
November 2010
Page 9.12
Atmospheric Emissions Table 9.10 and Table 9.11 show the maximum predicted SO2 concentrations for turbines during normal and abnormal operations at Quad204 FPSO and at Foinaven FPSO.
Objective values/ limit 3 (SO2) (µg/m )
Background
Total SO2 3 (µg/m )
Emission %
Emission % below limit
Emission % above limit
266
-
7.1
2.67
100
-
99.73 percentile of 1hour averages
350
-
6.94
1.98
100
-
Long-Term AQO (turbines)
99.18th percentile of 24-hour averages
125
-
5.13
4.10
100
-
Long-Term AQO (turbines)
Annual average
50
-
0.07
0.14
100
-
Objective
Measured as
Long-term AQO
99.9 percentile of 15-minute averages
(turbines) Long-term AQO
(turbines)
th
th
Table 9.10: Maximum predicted concentration and percentage concentration of SO2 (µg/m3) at the output grid
Objective values/ limit 3 (SO2) (µg/m )
Background
Total SO2 3 (µg/m )
Emission %
Emission % below limit
Emission % above limit
266
-
0.02
0.008
100
-
99.73 percentile of 1hour averages
350
-
0.0001
0.00003
100
-
Long-Term AQO (turbines)
99.18th percentile of 24-hour averages
125
-
0.006
0.0048
100
-
Long-Term AQO (turbines)
Annual average
50
-
0.0001
0.0002
100
-
Objective
Measured as
Long-term AQO (turbines)
99.9 percentile of 15-minute averages
Long-term AQO (turbines)
th
th
Table 9.11: Maximum predicted concentration and percentage concentration of SO2 (µg/m3) at Foinaven FPSO
November 2010
Page 9.13
Atmospheric Emissions Figure 9.11, Figure 9.12 and Figure 9.13 present the contour plots of the predicted 99.9th percentile of 15 minute average concentrations, the 99.73rd percentile for 1 hour averages and the 98.18th percentile of 24 hour average concentrations respectively.
Figure 9.13: Concentration of normal operation 1 to 99.18th percentile of the output Grid (SO2) µg/ m3
Figure 9.11: Concentration of normal operation 1 to 99.90th percentile of the output grid (SO2) µg/m3
Figure 9.12: Concentration of normal operation 1 to 99.73th percentile of the output grid (SO2) µg/m3
Page 9.14
November 2010
Atmospheric Emissions 9.5.2
Conclusions
Throughout the installation, commissioning and operation of the Quad204 Project, there will be additional levels of NOx, SO2, CO and VOCs released into the environment. Releases from FPSO operations will continue throughout the life of field and emissions from installation and commissioning vessels will be transitory. The effects from all these pollutants will be localised and due to the dispersive nature of the offshore environment and the remote location, they will have a negligible effect on the nearest receptors at Foinaven. With the distance to the Shetland mainland and the strongly dispersive wind regime of the area, it is not expected (as seen by the modelling results) that atmospheric emissions from the Quad204 Project will have detrimental impacts on the local environment. Major efforts have been incorporated into the Quad204 FPSO design and operations to improve energy efficiency and to reduce emission of pollutants to atmosphere. The base case for the Quad204 project is to use standard offshore dual fuel turbines but the turbines will be designed as dry low emission (DLE) ready (see Section 2.4.6), i.e. able to retrofit DLE turbines at a later date. DLE gas turbines can provide a reduction in NOX emissions compared to standard gas turbine technology. However DLE gas turbines are typically less efficient than standard dual fuel gas turbines, and therefore higher CO2 emissions may be seen. Future implementation of DLE technologies will be assessed by BP in line with technology readiness and legislation at the time of major overhauls of the turbines.
9.6
Cumulative and transboundary Impacts
The potential for cumulative effects from the Quad204 Project was assessed through air dispersion modelling using maximum predicted concentrations from Quad204. The assessment showed that emissions from the Quad204 project will have limited cumulative effect and any changes in ground level concentrations at the nearest landfall (or in this instance, the Foinaven FPSO) will be negligible. As identified above, the effects of the released NOX, SO2 and VOC emissions from the Quad204 FPSO, including vessel emissions, will be localised, and any transboundary impacts will be negligible. In SEA 4, DECC stated that: h “Potential environmental effects of acid gas and greenhouse emissions are, respectively, regional and global in nature. Local environmental effects of atmospheric emissions are not expected to be significant in view of the high atmospheric dispersion associated with offshore locations; h Combustion emissions from power generation would represent only a minor contribution to oil and gas production industry, other industry and national totals. h That incremental contributions to regional and global effects will not be significant” (DTI, 2003).
Other technologies incorporated include waste heat recovery systems on the turbines, where energy normally lost to atmosphere will be recovered and reused to satisfy process heating requirements. A flare gas recovery system which redirects gas back into the process system offers a significant reduction in emissions to atmosphere caused by flaring. Other technologies include installation of a vapour recovery unit on the FPSO that will significantly reduce emissions of VOCs during production and storage of produced fluids. Shuttle tankers with VOC recovery systems will be used. Fugitive emissions have been reduced in design where possible, by limiting the number of connections and flanges and therefore potential leak sources.
November 2010
Page 9.15
Atmospheric Emissions
This page has been deliberately left blank
Page 9.16
November 2010
Accidental Events
10 Accidental Events This chapter describes the measures that will be put in place during the Quad204 Project to prevent spills arising from accidental events, and proposed contingency measures that will be employed to ensure an effective response in the event of a spill.
10.1 Introduction It is BP’s aim to cause no damage to the environment by minimising the risk of spills using measures relating to plant, people and processes. In light of the Deepwater Horizon incident in the Gulf of Mexico, this chapter incorporates emerging, relevant information from the incident while recognising that the Quad204 drilling programme consists of infill development drilling into a reservoir which does not contain fluids at high pressure or temperature and in which more than 50 wells have been drilled since the 1990s.
The philosophy of the Quad204 Project is to reduce the likelihood of oil spill events at source through design and operational practices. There is not a linear relationship between spill size and the extent of environmental impact. In the offshore environment, the likelihood of impact of an oil spill will be determined by the direction of travel of the slick, its weathering properties and whether environmental sensitivities are present in its path. These environmental sensitivities will have spatial and temporal variations. The likelihood of any oil spill having an impact on the coastal environment is more complex as it must consider the likelihood of the oil spill occurring against the probability of that oil beaching and the environmental sensitivities present at the time of oil beaching. The following sections also look at the potential spill risk from Quad204 Project activities. The terminology in Table 10.1 for probability has been adopted:
Experience gained from the existing Schiehallion FPSO has assisted in identifying specific areas where design modifications have been made on the new Quad204 FPSO to reduce the risk of oil and chemical spills and these have been identified below in the appropriate sections.
Term used
Probability*
Likely
more than once per year
Possible
once every 1-10 years
Improbable
once every 11-100 years
Accidental events such as vessel collision and dropped objects are also possible risks from the Quad204 Project and these are covered in Chapter 6 – Physical Presence, however the spill risk from vessel collision has been addressed in this chapter. It should be noted that Schiehallion has undertaken detailed spill response planning and a number of key response measures are already in place e.g. spill response equipment located in Shetland.
Remote
once every 101-1000 years
Extremely remote
once every 1001-10,000 years
The potential sources of oil or chemical spills to sea from the Quad204 Project are identified in the EIA matrix (Appendix D). The matrix formally records the output from the ENVID workshops and includes the environmental aspects, potential impacts and existing control and mitigation measures. The ENVID process recognised that the most significant oil spill risks are potentially associated with uncontrolled blowouts during drilling, and major loss of containment from the FPSO cargo inventory, although such events are extremely unlikely to occur. Potential sources of smaller spills identified included bunkering of diesel fuel and muds and release of hydrocarbons via grated decks.
* Relative to years of operation, i.e. 5 installations operating for 6 years each is equivalent to 30 years Table 10.1: Terminology adopted to describe oil spill probability
In addition to comprehensive prevention measures, integral to any BP operation is the formulation of detailed and fully tested contingency response plans appropriate to local environmental sensitivities. The EIA process has identified the key environmental sensitivities related to oil spills and the behaviour of Schiehallion hydrocarbons when spilled at sea has been modelled in order to draft a Quad204 Project specific oil spill response strategy. Detailed spill response strategies will be finalised for both drilling and production prior to the commencement of operations and this will be documented in the Oil Pollution Emergency Plans (OPEPs) for the mobile offshore drilling unit (MODU) and the Quad204 FPSO which will be submitted to DECC for approval.
10.2
Regulatory control
The key regulatory drivers that will assist in November 2010
Page 10.1
Accidental Events reducing the possible occurrence of an oil or chemical spill (and mitigating the effects of the same) are described in Appendix A and summarised as follows: h The Merchant Shipping (Oil Pollution Preparedness, Response and Co-operation Convention) Regulations 1998. The International Convention on Oil Pollution, Preparedness, Response and Co-operation (OPRC), which has been ratified by the UK, requires the UK Government to ensure that operator’s have a formally approved OPEP in place for each offshore operation, or agreed grouping of facilities. h Offshore Installations (Emergency Pollution Control) Regulations 2002. These Regulations give the Government power to intervene in the event of an incident involving an offshore installation where there is, or may be a risk of significant pollution, or where an operator has failed to implement proper control and preventative measures. These Regulations apply to chemical and oil spills. h EC Directive 2004/35 on Environmental Liability with Regard to the Prevention and Remedying of Environmental Damage. The Environmental Liability Directive enforces strict liability for prevention and remediation of environmental damage to ‘biodiversity’, water and land from specified activities and remediation of environmental damage for all other activities through fault or negligence.
10.3
Oil spills
The structure set out below includes the background and risk assessments for those areas of the project where oil could be released into the environment. The historical data for frequency of
spill events from the UKCS are reviewed and used to inform oil spill modelling. This in turn, is used to build oil spill response plans and emergency procedures to aid in reducing any potential impacts in the unlikely event of a significant spill. These plans and procedures will be incorporated into the MODU and Quad204 OPEPs. Analysis of the UKCS historical data between 1975 and 2005 (UKOOA, 2006) shows that the majority of spills from offshore oil and gas operations are small i.e. less than 1 tonne. UKOOA (now Oil and Gas UK) reports that since 1975 46% of spill records relate to crude oil, with 18% relating to diesel, and the other 36% relating to other hydrocarbons such as condensates, hydraulic oils, oily waters and unknown types of oil. Tina Consultants Ltd (2010) reports that on the UKCS during the period 1975 to 2007 a total of 17,012 tonnes of oil (excluding regulated discharges from produced water systems, but including spills of base oil and OBM) were discharged from 5,826 individual spill events (Figure 10.1). It is also noted that while the number of reported oil spills increased over this period, since 1990 (with the exception of 1997) the overall volume of oil spilled has been substantially reduced.
10.3.1 Blowouts Background Primary well control is the process which maintains hydrostatic pressure in the wellbore greater than the pressure of the fluids in the formation being drilled, but less than the formation fracture pressure. If formation pressure is greater than the pressure of the fluid in the wellbore (i.e. mud hydrostatic pressure) the well will flow and an influx will enter the wellbore. This flow is stopped
Figure 10.1: Number of oil spills and amounts spilled in the UKCS (TINA Consultants ltd, 2010)
Page 10.2
November 2010
Accidental Events by closing the blowout preventer (BOP) which is the initial stage of secondary well control. Secondary well control is completed by circulating out the influx and displacing the wellbore to the new kill weight fluid. If primary and secondary well control fails a surface blow out may occur. A surface blowout is defined as an uncontrolled flow of formation fluids from the reservoir to the surface which occurs as a result of loss of primary and secondary well control, resulting in the potential for release of hydrocarbons to the environment. An underground blowout is when downhole pressure exceeds the fracture pressure of a formation and fluids flow into the weaker formation. Sources and likelihood of occurrence The historical data for frequency of blowouts from MODUs occurring on the UKCS between 1990 and 2007 are shown in Table 10.2. Note that the data do not indicate the severity of the event or the probability of that blowout leading to an oil spill.
Type of Facility
MODUs
Period 1990-1999
2000-2007
Further risk mitigation comes from a consideration of the primary and secondary well control elements in place for Schiehallion and Loyal wells. The Quad204 reservoir target sands are normally pressured at 1.04 sg, meaning that a seawater hydrostatic pressure would balance the formation pressures. Mud weights selected to drill the hole sections, once the BOPs are installed, are determined by wellbore stability requirements to ensure that the shales remain stable and are in the range of 1.15 - 1.25 sg. Mud weights within the reservoir sand intervals are in the range 1.2 - 1.25 sg. Therefore planned mud weights are in excess of the reservoir pressures and the probability of a blowout is reduced. In a fluid loss situation, maintaining the well full of seawater would balance any formation pressures. BOP equipment, being safety critical equipment, receives a high degree of focus to ensure that it is built and maintained as per the original equipment manufacturer (OEM) specification and tested on a regular basis to confirm the operation of the control system / components and pressure integrity.
1990-2007
No
Freq
No
Freq
No
Freq
13
0.020
3
6.6 x -3 10
16
0.014
Table 10.2: Blowout frequency per unit year on UKCS (Oil and Gas UK, 2009)
The most recent serious UK blowout was in 1988 when an explosion led to a fire on a semisubmersible rig drilling a high pressure high temperature field in the Central North Sea. Table 10.3 uses the International SINTEF database of wells drilled in waters greater than 200 m to calculate the projected frequency of blowout and well release incidents from the proposed project based on the expected drilling schedule and time scale for completion of the development wells. These data do not provide a probability of the blowout or well release leading to an oil spill. It is however observed that gas release frequency is much higher than oil release frequencies for drilling blowouts and well releases. Wells with a gas to oil ratio (GOR) of 1,000 or greater have a higher probability of blowout (Scandpower, 1999). Typical initial GOR (approximately 380 scf/stb for the Schiehallion and 512 scf/stb for the Loyal reservoirs) is not considered significantly high, and the risk of blowout from the reservoir is considered to be low. In addition, the existing Schiehallion/Loyal field development has a drilling record which has spanned 16 years with over 50 November 2010
wells drilled and has provided extremely good understanding of the reservoir characteristics.
Spill prevention and contingency planning The following provides a high level overview of proposed areas of planning and preparation that either reduce the probability of a failure of well control and/or reduce the consequence of a failure of well control on Quad204 wells. A more detailed OPEP will be submitted to DECC for consideration and approval in advance of the commencement of the Quad204 drilling programme. h The Quad204 wells are designed to the requirements of BP’s Engineering Technical Practices. None of the wells are high pressure or high temperature. In fact, gas lift is required to maximise recovery from the Schiehallion and Loyal reservoirs.
Page 10.3
Accidental Events Scenario
Generic estimate of spill frequency Blowout*
Well release**
Historical frequency per 4 well year
Predicted frequency per year at 5 Quad204 area
Predicted number of years per 5 incident
Historical frequency per 4 well year
Predicted frequency per year at 5 Quad204 area
Predicted number of years per 5 incident
4.70E-04
1.14E-03
876
2.30E-04
5.59E-04
1790
(1),(2)
4.50E-04
1.09E-03
915
3.60E-04
8.74E-04
1144
(2)
3.80E-05
6.46E-04
1548
1.30E-05
2.21E-04
4525
9.10E-04
9.10E-04
1099
1.10E-03
1.10E-03
909
All scenarios (Drilling (1) period)
1.87E-03
3.79E-03
264
1.70E-03
2.75E-03
363
All scenarios (Post drilling period)
9.48E-04
1.56E-03
643
1.11E-03
1.32E-03
757
Development drilling (1),(2)
Completion
Production
(3)
Workover
* SINTEF (2010) do not include detailed information on the blowout/well release severity but note that most blowouts/well releases do cause relatively small damages ** Oil or gas flowed from the well from some point where flow was not intended and the flow was stopped by use of the barrier system that was available on the well at the time the incident started Notes: (1)
Assumes development drilling and completion only in first 7 years of Quad204 Project
(2)
Assumes 17 production wells
(3)
Assumes 1 x workover operation per year
(4)
Based on SINTEF international data for wells in water >200 m (2010)
(5)
Based on approach from Scandpower (1999) Table 10.3: Projected frequency of blowout and well release incidents for Quad204 Phase 1 drilling programme
h While drilling, the primary well control barrier in the main conduit (i.e. the annulus immediately around the drill pipe) will be weighted mud and the secondary barrier is the BOP equipment. In addition, previous casings in the next annulus out also have barriers, i.e. seal assemblies in casing hangers, and cement isolation between reservoir and surface - of which there may be one or more set in each annulus. h The wells will be drilled using a MODU designed for the West of Shetland environment. The rig will have a UK safety case and will be class certified by a recognised certifying authority. BP will perform assurance audits prior to rig acceptance to confirm all critical systems such as subsea and surface blowout prevention equipment and drilling fluid circulating and processing systems are fully certified and working as designed. h The MODU will have a minimum 10,000 psi BOP stack (standard for MODUs). The BOP Page 10.4
stack minimum pressure rating will always be greater than Schiehallion and Loyal reservoir pressure. h Surface spill response will comply with UK regulatory requirements including aerial surveillance capability and dispersant spraying capability. Natural dispersion by wave action is the preferred method of dispersion. Surface dispersants will also be used where necessary to mitigate risks to personnel, and should any sensitive resources be threatened by surface oil. The application of dispersant onto fresh oil will be considered based on the circumstances at the time, and in consultation with the authorities. In common with other BP West of Shetland assets, standby vessels will also be equipped with dispersant capability, and the BP Onshore Oil Spill Plan is in place, encompassing resources and personnel to combat oil spills approaching coastal areas of Shetland. h Given the potential variability of a well failure November 2010
Accidental Events event, BP will have in place a variety of scenario plans to enhance response effectiveness and reduce response time. These will include consideration of pressure and flow monitoring equipment, back-up BOP operation, intervention intervention by suitably rated vessels and equipment, compatibility of BOP and Lower Marine Riser Package connectors with capping equipment. h The Quad204 Project will comply with BP corporate requirements for relief well preparedness, and candidate rigs operating in the UK or Norway Continental Shelves will be identified. h The BP Well Control Response Guide details the action to be taken in response to a well control event and defines the roles and responsibilities for all responders to the event and details technical and operational support for different scenarios. This includes the requirement for bridging documents defining the respective actions to be taken by BP and contractors in the event of an incident. h The proposed measures will be documented in BP’s OPEP for consideration by the authorities prior to drilling any wells and measures will be employed in relation to the risks posed from the various operations. The OPEP will reflect emerging lessons learned from the Deepwater Horizon incident for example, the Deepwater Horizon Accident Investigation Report (BP, 2010d)
Blowout spills: summary The likelihood of a blowout event leading to a spill, particularly from the drilling of development wells in low energy reservoirs such as Schiehallion and Loyal, is considered remote - extremely remote. Nevertheless as the consequences of a blowout are significant, BP will implement measures to reduce the probability of a failure of well control and reduce the consequence of a failure of well control on Quad204 wells.
10.3.2 MODU spills Background The Quad204 drilling programme at the Schiehallion and Loyal fields outlines that 25 wells (comprising 17 producers and 8 water injectors) will be drilled from a mobile offshore drilling unit(s) (MODU) (specifically semi-submersible drilling rig(s)) during Phase 1. Potential spills from MODUs may be caused by mechanical failure, operational failure or human error. Sources and likelihood of occurrence The data presented in Table 10.4 are based on data submitted to DECC from the period 2001 2007. During this period, the rigs in operation on the UKCS had a total of 172 years of operation. No spills ≥ 100 tonnes were recorded on the UKCS between 2001 and 2007 and the majority of spills recorded were less than 1 tonne.
Spill cause
<100 ≥10 tonnes
<10 ≥1 tonnes
<1 ≥0.1 tonnes
<100 ≥ 10 kg
<10 ≥ 1 kg
<1 kg
All spills*
Maintenance/ Operational activities
**
1
5
4
14
10
35
Bunkering
**
**
9
2
9
2
22
Subsea releases
1
2
1
3
3
1
12
Drilling
1
2
15
15
6
12
54
ROV associated
**
**
**
1
3
1
5
Other production
**
**
1
**
**
**
1
All spills***
2
8
42
40
42
35
179
* Includes spills of unknown size ** Did not occur within the report period *** All spills include spills of unknown cause and spills that could not be categorised Table 10.4: Number of spills from a MODU based on UKCS historical data by spill size and source during the period 2001 - 2007 (TINA Consultants Ltd personal communication, 2010)
November 2010
Page 10.5
Accidental Events The number and frequency of spills per unit year from MODUs, on the UKCS between 1990 and 2007 are shown in Table 10.5, with the number and frequency of spills decreasing between the two periods compared during this time.
Hydrocarbon
Maximum storage volume 3 (m )
Surface mud pits (60% oil content)*
2,116
Diesel and base oil
2,819
Lube and hydraulic oil
59
Aviation fuel
3
Total
4,997
Period Facility
MODU
1990 – 1999
2000 – 2007
Overall (19902007)
No
Freq
No
Freq
No
Freq
160
0.246
78
0.172
238
0.215
Table 10.5: Number and frequency of spills per unit year from MODUs in the UKCS, 1990 - 2007 (Oil and Gas UK, 2009)
Table 10.6 highlights the number and frequency of explosions, collisions and vessel contacts per unit year for MODUs. These data indicate a reduction in the frequency of such incidents between the two time periods compared: while not indicating whether or not a spill occurred from the explosion, collision or vessel contact, the data indicates that the likelihood of incidents which could lead to a spill is decreasing.
Period Facility
1990 – 1999
2000 – 2007
Overall (1990-2007)
No
Freq
No
Freq
No
Freq
Vessel ContactMODU
108
0.166
25
0.55
133
0.120
Collision MODU
14
0.021
1
0.0022
10
0.014
Explosion MODU
10
0.015
-
-
10
0.009
Table 10.6 Number and frequency of explosions, collisions and vessel contacts per unit year for MODUs in the UKCS, 1990 - 2007 (Oil and Gas UK, 2009)
The worst-case spill scenario from MODUs (other than blowouts) would be from structural damage leading to total loss of hydrocarbon inventory, although this is unlikely as hydrocarbon stock is stored in multiple locations. Table 10.7 details the hydrocarbon inventory on a typical MODU (the Paul B Loyd Junior (PBLJ), a semi-submersible drilling rig was used to provide example MODU specifications). The largest potential fuel inventory is the marine diesel stored onboard the MODU. However it is unlikely that the total capacity of fuel storage would ever be reached and maintained for extended periods. Page 10.6
* Worst case scenario as mud pits may contain water based muds Table 10.7: Maximum hydrocarbon inventory on a typical MODU (PBLJ)
Spill prevention and contingency planning BP will implement the following management and mitigation measures to prevent and/or minimise the likelihood of any oil spill from the MODU and to mitigate the impact of any such spill: h The MODU will be suitable for the operating environment encountered in the Quad204 Project area h The MODU will comply with International Maritime Organisation (IMO)/Maritime and Coastguard Agency (MCA) codes for prevention of oil pollution, and will maintain an onboard Shipboard Oil Pollution Emergency Plan (SOPEP) h An OPEP will be in place for the drilling operations carried out by the MODU once it is in place h Approach procedures and poor weather operational restrictions for visiting vessels and transfer operations at the MODU will be defined prior to operations h Fuel handling, transfer and monitoring procedures will be put in place h Pre-mobilisation audits of vessels including a detailed list of contract requirements in terms of spill (both oil and chemical) prevention procedures will be put in place h Lube and hydraulic oils will be stored onboard in tanks or sealed drums, which pose a minimum risk of spillage. In addition, drums and storage tanks for hydrocarbons will be well secured and stored in contained areas h Procedures will be put in place for bunker transfer, other bulk storage transfers and mudhandling in order to minimise the risk of spillage November 2010
Accidental Events Spill size categories
<10 ≥1 tonnes
<1 ≥0.1 tonnes
<100 ≥ 10 kg
<10 ≥ 1 kg
<1 ≥ 0.1 kg
<100 g ≥ 10 g
All spills*
Fixed
6
5
7
3
1
1
23
Floating
1
**
**
**
2
**
3
All spills***
7
5
7
3
3
1
27
* Includes spills of unknown size ** Did not occur within the report period *** All spills include spills of unknown cause and spills that could not be categorised Table 10.8: Number of spills from subsea tiebacks to oil producing facilities (1975 – 2007) (TINA Consultants Ltd, personal communication 2010)
h Oil spill kits, including absorbent material, will be available on board the MODU and vessels to allow clean up of any deck spills or leaks
MODU spills: summary The most probable MODU spills, based on historical data, are small spills of < 1 tonne BP has focused on prevention of these spills through rig specification and implementation of agreed operational procedures which will reduce the likelihood of spills to sea
1975 and 2007, over 70% were <1 tonne. There have been 3 spills reported from subsea tiebacks to floating oil producing facilities in the period 1975 – 2007 (TINA Consultants Ltd, personal communication 2010). The frequency of spills from subsea facilities is improbable-remote as shown by Table 10.8. Flowline leak sources can be divided into those caused by corrosion and those caused by impact damage. Impact damage may be caused by a number of events including fishing gear impact, anchoring impact, and impact from other dropped objects. Based on generic North Sea data, leaks due to corrosion and impact damage are remote events (see Table 10.9). Spill prevention
10.3.3 Subsea facilities Background Spill risks from subsea facilities are largely associated with structural failures of equipment including flowlines, control lines and valves at the manifold or wellhead.
BP will implement the following management and mitigation measures to prevent and/or minimise the likelihood of a spill from the installation and operation of the subsea facilities. h Flowline design specification and use of appropriate design codes for, example, corrosion allowance
Sources and likelihood of occurrence
h Use of corrosion inhibitor
Of all spills reported from subsea facilities between
h Emphasis will be placed on appropriate
Cause of flowline loss
Spills per flowline years for the longest flowline 9 km
Spills per flowline years for the shortest flowline 3 km
Flexible flowline
10 - 16" steel flowline
Flexible flowline
10 - 16" steel flowline
Impact event within rig/FPSO safety zone
8.04 x 10-4
1.49 x 10-3
8.04 x 10-4
1.49 x 10-3
Impact event within subsea well safety zone
3.85 x 10-3
4.06 x 10-3
3.85 x 10-3
4.06 x 10-3
Impact event in midline sections
4.68 x 10-3
3.1 x 10-4
1.17 x 10-3
7.74 x 10-5
Corrosion
6.96 x 10-3
1.22 x 10-3
6.49 x 10-3
1.19 x 10-3
Total (all events)
1.63 x 10-2
7.08 x 10-3
1.23 x 10-2
6.82 x 10-3
Table 10.9: Projected frequencies of flowline leak incidents leading to loss of hydrocarbons (Source: AME, 1998)
November 2010
Page 10.7
Accidental Events contractor selection, quality management systems and equipment maintenance
Subsea spills: summary
h Intelligent pigging will be routinely planned during the life of the flowlines on a risk-based methodology. Intelligent pigs are primarily used to measure wall thickness loss in order to determine presence or extent of internal corrosion. h Proactive pipeline inspection and maintenance programme BP operates a risk-based Pipeline Integrity Management Scheme (PIMS) for each asset which is in line with best industry practice. This system will be used for design and implementation of an inspection and maintenance system for the new Quad204 Project flowlines. A central feature of the PIMS is a detailed pipeline risk assessment to identify potential failure modes and mechanisms, probability and time dependence of failure, consequences of failure and overall risk of failure. Routine maintenance of flowlines consists of regular visual inspection of all flowline systems for integrity; the frequency of inspection is determined by PIMS. If the inspection regime identifies any defects, then the necessary corrective maintenance will be performed (e.g. use of corrosion inhibiting chemicals, or replacement of flowline). To date flowlines at Schiehallion and Loyal have had no major issues in terms of integrity maintenance.
The likelihood of a spill from the production flowlines is remote - extremely remote. Prevention measures in place (including a proactive monitoring system) will maintain an extreme low probability of any oil spills.
10.3.4 FPSO operations Background Spill risks from FPSO facilities are largely associated with maintenance and operational activities. Sources and likelihood of occurrence The data presented in Table 10.10 is from the period 2001-2007 when there were 21 – 23 floating oil producing facilities which had a total of 161 years of operating. No spills ≥ 100 tonnes were recorded on the UKCS between 2001 and 2007. Spill prevention BP will implement the following management and mitigation measures to prevent and/or minimise the likelihood of a spill from the FPSO. h The FPSO is designed with a double bottom and double sided hull to reduce the possibility of hydrocarbon loss from grounding and collision h Design measures have been incorporated into the new FPSO to contain minor spills e.g. the use of scuppers to allow plugging in the event of small spills on deck to stop hydrocarbon
Spill cause
<10 ≥1 tonnes
<1 ≥0.1 tonnes
<100 ≥ 10 kg
<10 ≥ 1 kg
<1 kg
All spills*
Produced water
7
1
**
**
**
8
Other production
1
4
1
**
**
6
Maintenance/ Operational activities
1
8
6
8
1
24
Bunkering
**
3
1
1
1
6
Subsea releases
**
3
7
1
**
11
Drilling
**
**
**
1
**
1
All spills***
9
19
15
11
2
54
*Includes spills of unknown size ** Did not occur within the report period. *** All spills include spills of unknown cause and spills that could not be categorised. Table 10.10: Number of spills from floating oil production facilities (TINA Consultants Ltd pers. comm., 2010)
Page 10.8
November 2010
Accidental Events release to the sea and bunded areas on the process decks to contain any small oil spills h Bunkering reels will be in place for all hoses on the FPSO including the export hose with adequate bunding and spills containment connected to drains h Utility stations for temporary equipment will be set up with diesel points running to them thus avoiding the need for temporary hoses h Minimisation of potential spills or overflows from diesel storage and transfer systems through good tank design and metering Procedural measures e.g. for diesel transfer will also be developed before operations commence at the Quad204 FPSO. All storage tanks, pipework and separators will be regularly inspected for corrosion and leaks and bulk loading transfer hoses will be regularly inspected. All personnel in charge will be appropriately trained according to BP’s procedural requirements and regulatory requirements and the FPSO will regularly exercise its oil spill response plans. A system will be in place for the reporting of all spills to meet statutory reporting requirements and to form part of a continuous ‘lessons learned’ cycle. Any FPSO spills are likely to be small with the majority < 1 tonne. The Quad204 Project has focused on prevention of these spills through FPSO design specification and implementation of operational procedures which will reduce the likelihood of spills to sea.
10.3.5 Shuttle tanker and vessel operations Background In addition to spill risks associated with the FPSO and its supply/standby vessels, spill risks are also associated with shuttle tanker operations, including loading of crude oil for export and the tanker route. Spill risks include operational spills during crude offloading and collision/grounding risks of the shuttle tanker. The probability of a collision or grounding risk is extremely remote and to date there have been no such spills associated with the Schiehallion shuttle tanker, Loch Rannoch. The overall increase in oil spill risk as a result of the Quad204 Project is considered to be negligible in relation to the existing shuttle tanker operations, particularly as there are loading procedures and spill prevention measures already in place.
Vessel spill prevention A number of measures will be implemented to reduce the risk of oil spills from supply, standby and installation vessels. These include: h Selection of supply/standby vessels which comply with IMO/MCA codes for prevention of oil pollution h Use of vessels, where possible, which have a track record of operating in the harsh west of Shetland environment h Pre-mobilisation audits will be carried out on all vessels including a comprehensive review of spill prevention procedures h Documented records for inspection of all hydraulic and hydrocarbon transfer hoses h Documented maintenance of bilge systems h Preferred operational procedures to be in place onboard vessels including use of drip trays under valves, use of pumps to decant lubricating oils, use of lockable valves on storage tanks and drums h Drums and storage tanks for hydrocarbons to be well secured and stored in contained areas h All vessels will have onboard Shipboard Oil Pollution Emergency Plans (SOPEPs) h Availability of absorbent material on board vessels to clean up any deck spills or leaks and suitable storage and disposal procedures for waste oil h Reels and hoses used for hydrocarbon transfer will be designed to reduce the likelihood of spills h Lessons learned from any offloading incidents elsewhere in BP will be applied. A number of measures will also be in place to reduce collision risk (also see Chapter 6): h Mandatory 500 m safety zone around FPSO and drill centres h Operational restrictions on visiting vessels in bad weather h Defined vessel no-go areas within safety zone h Agreed approach procedures to FPSO by supply and standby vessels h Standby vessel will be present Vessel personnel will be given training in spill prevention and actions to be taken in the event of a spill. A system will be in place for the reporting of all
November 2010
Page 10.9
Accidental Events spills. As well as meeting statutory reporting requirements, any spill reports will form part of a continuous ‘lessons learned’ cycle. Vessel spills: summary The likelihood of a major spill from a vessel is extremely remote. Most likely vessel spills are small (< 1 tonne).
10.4
Behaviour of oil at sea
The environmental impact of an oil spill depends on a wide variety of factors, which in the offshore environment include: h Spill volume h Direction of travel of the slick h Weathering properties of the crude h Any environmental sensitivities present in the path of the slick (these may also have temporal variations in sensitivity h Sensitivity of the beaching locations
10.4.1 Overview of modelling undertaken Oil spill modelling using the Schiehallion crude OSIS constants was undertaken using the Oil Spill Information System (OSIS) Version 4.2.2 model (OSRL, 2010) and the Oil Spill Contingency and Response (OSCAR) version 5.0 model to gain an understanding of the behaviour of a potential spill and its associated environmental impacts. The OSIS model is the model normally used in the UKCS to model the behaviour of hydrocarbon on the sea surface. The model can be used to model the route of an oil slick over time, to estimate the oil weathering profile and estimate the likelihood of particular trajectories occurring. An alternative model, OSCAR is used by Norwegian regulators and industry to predict the fate and impacts of oil and to model the effectiveness of response measures. This model calculates and records the distribution of a contaminant over a period of time on the water, along shorelines, in the water column, and in the sediments. The functionality of OSCAR to model subsurface releases has been noted by OSPRAG (the Oil Spill Prevention and Response Advisory Group established in the UK after the Deepwater Horizon incident) and is therefore applied to the Quad204 Project to model ongoing subsurface releases and their effects on the water column. The OSIS modelling considered a range of spill scenarios from the FPSO and wells (Table 10.12). Stochastic simulations were undertaken for both Page 10.10
summer and winter conditions for each spill scenario. Under these scenarios wind rose data and sea air temperatures were taken from the environmental description (see Section 4.2 and 4.3). Sea surface temperatures were sourced from BP’s data. All scenarios run assumed “worst case”, i.e. no response measures were undertaken. To undertake OSCAR modelling, stochastic analysis with input of the range of real wind conditions experienced at the site was considered. To complete the three years’ data needed for the model, recent wind data collected at the Schiehallion FPSO has been incorporated. This gives site-specific wind data and is consequently the best possible basis for predicting wind-driven effects such as surface oil. The year on year variation in this data generated a range of outcomes for each scenario. To illustrate this variation, each year is shown for the blowout scenario (Figure 10.2), and for subsequent scenarios, outputs from the year which generated the worst case scenario are also shown within the Figures. Current data have been sourced from the SINTEF 1990 database which gives the range of subsea currents experienced over the annual cycle. The subsea current data has a resolution of approximately 2 km and has data relating to 16 separate depth bands covering the full water depth in the Schiehallion FPSO location. Table 10.11 presents the predicted minimum times for beaching probabilities for spill scenarios in constant wind (with no response activated).
10.4.2 Schiehallion crude Schiehallion crude constants were used as inputs to the OSIS and OSCAR modelling. Schiehallion crude oil is a very high viscosity (220 cP at 12.5°C) and high density crude that contains a relatively low proportion of volatile components (IKU, 1995). OSCAR modelling predicts that approximately 1520% of the oil will be lost by evaporation in the first few hours after a spill from a subsea blowout, and 25-30% evaporation from a large surface loss of contaminant. Asphaltene and wax components will be precipitated from the oil by this change in composition and at winter sea temperatures (7.8°C) wax precipitation will be greater and the oil may become semi-solid. Weathering studies undertaken (IKU, 1995) show that Schiehallion crude oil if spilled at sea will rapidly form stable water-in-oil emulsions with up to 75% water content by volume. These water-inoil emulsions will be of moderate viscosity (10,000 cP after five days weathering at 12.5°C). At low to moderately high wind speeds (4 to 20 knots), the emulsion formed from weathered Schiehallion November 2010
Accidental Events Scenario
Hydrocarbon Type
Spill Volume and Rate
Spill Location and Depth
Model used
1) Blow out with capping after 90 days
Schiehallion crude
Natural flow rate of well in event of blow out estimated to be 133 3 m /hr*. Release over 90 days. 3 Total of 287, 280 m .
Seabed release below drilling rig at the Schiehallion Centre drill location
OSCAR
2) Total loss of diesel inventory from the FPSO **
Diesel
Diesel based oil inventory based on the worst case scenario is 3 6944 m . Instantaneous release.
FPSO at surface
OSIS
3) Total loss of hydrocarbon inventory from the FPSO **
Schiehallion crude
Schiehallion crude hydrocarbon inventory on the FPSO based on the worst case scenario is 3 172,560 m . Release over 1 hour.
FPSO at surface
OSCAR
4) Medium sized diesel spill
Diesel
1000 m Instantaneous release
FPSO at surface
OSIS
3
* This is a conservative assumption that the well would continue to flow at this rate throughout the 90 day period; as the Schiehallion reservoir is a low energy reservoir, the flowrate would naturally decrease over this period. ** This is a worst case scenario as diesel/oil will be stored in a number of tanks and spill volume is likely to be the contents of a single tank rather than total diesel/oil storage volume. Table 10.11: Scenarios selected for oil spill modelling for the Quad204 Project
crude oil will be persistent on the sea surface because the moderately high viscosity of the water-in-oil emulsions will resist natural dispersion. At very high sustained wind speeds (30 knots or greater), although water-in-oil emulsions will be formed extremely rapidly, the rate of natural dispersion will be high, eventually leading to the almost total natural dispersion of smaller sized spills after several days at sea.
10.4.3 Uncontrolled blowout in the Quad204 Project area In the light of the Deepwater Horizon incident in the Gulf of Mexico, a 90 day uncapped well blow out scenario was considered for the purposes of oil spill modelling and contingency planning for the Quad204 Project representative of the time taken to drill a relief well and stop an uncontrolled blowout. Due to modelling constraints, it was not possible to produce an OSIS output for the 90 day subsea spill scenario and therefore modelling was conducted using the OSCAR model.
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Oil spill modelling Deterministic and stochastic modelling are two types of oil spill fate modelling. These tools are both used in oil spill contingency planning to assess what response resources should be located where to respond most effectively in the unlikely even of an oil spill large enough to reach the shoreline. Deterministic modelling predicts spill behaviour in a given wind direction to identify minimum, worst case beaching times under extreme weather conditions, albeit these conditions may never occur in reality e.g. constant 30 knot onshore wind from Quad204 to Shetland for 105 hours. The information obtained from deterministic modelling contributes to the development of shoreline response – providing a worst case or minimum time interval for initiation of response (Table 10.12). Stochastic modelling uses actual wind data collected over a period of time to establish a statistical picture of probability of coastline pollution in different locations. This contributes to the locating of shoreline response resources: focusing resources on areas most probably affected in the unlikely event of oil beaching, rather than on area where modelling indicates oil will not beach (Figure 10.2 to Figure 10.4).
Page 10.11
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Winter
Summer
30 knots offshore (UK-Faroe median line)
30 knots onshore (Shetland)
30 knots offshore (UK-Faroe median line)
Total loss of diesel/base oil inventory from MODU
Minimum time to beaching/reaching international waters (hrs)
Does not beach
Does not beach
Does not beach
Does not beach
Blow out with cessation after 90 days
Minimum time to beaching/reaching international waters (hrs)
105
78**
198
75***
Total loss of hydrocarbon inventory from the FPSO
Minimum time to beaching/reaching international waters (hrs)
54
30*
54
27*
Medium sized diesel spill
Minimum time to beaching/reaching international waters (hrs)
Does not reach
Does not reach
Does not reach
Does not reach
*Modelling can produce a beaching scenario in Faroe within 28 days however the statistical record of winds in this area means there is zero possibility of this happening **Modelling can produce a beaching scenario in Faroe within 17 days however the statistical record of winds in this area means there is zero possibility of this happening *** Modelling could not produce a beaching scenario in Faroe to occur for a period of 25 days Table 10.12: Predicted minimum times for beaching probabilities for spill scenarios in constant wind (with no response activated)
Modelling indicates that the oil released from the blowout moves to the north and north east of the release point, and of Shetland, by the shelf current and the prevailing south westerly winds (Figure 10.2) which results in the majority of oil degrading and dispersing without beaching. Assuming no response is undertaken (a situation that would never occur), a maximum of less than 1.5% (889 to 2,975 tonnes of oil) of the total quantity of oil released is predicted to beach, but this occurs in the most pessimistic weather conditions encountered in the period of wind data analysed i.e. constant 30 knots onshore winds in 2.9 days, in other scenarios a smaller quantity would beach. Oil that does reach the Shetland shoreline may beach in a minimum of 3.6 days if prevailing winds took the oil directly to shore. Although under typical weather conditions (this refers to the most commonly occurring wind speeds and directions which occurred during the time periods for which wind data were available) beaching would be anticipated to occur in a minimum of 4 days and 9 hours. The model (Figure 10.2) indicates a 0-10% probability of oil beaching on the coastlines of the
north of Scotland, Orkney, Norway and zero probability in the Faroes. Near the release site the oil will disperse throughout the water column and much of the overall depth of the water column will be affected in a relatively narrow band in the direction of the prevailing currents, to the northeast. The oil in the water column is more concentrated in the upper 50m although some oil may be present at any depth, and beyond approximately 10 km from the release, water column concentrations are predicted to be typically sub -100 ppb (with local variations around this level). Away from the prevailing current direction, the model predicts little or no oil presence. At day 90 of the release, when the maximum amount of oil has been released, it is predicted that 32% of the oil will already have decayed in the water column by microbial action. A further 22% is predicted to have evaporated, 13% to have deposited on sediments with 32% dispersed in the water column. Typically less than 1% is predicted to have beached or remain on the surface at 90 days. This figure can vary depending on the conditions and time of year, but less than 1.2% of oil is predicted to beach in any scenario.
Year 1
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Year 2 – Worst Case
Year 3
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Page 10.13
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Figure 10.2: Probability of surface oiling and beaching locations from blowout lasting for 90 days without response in the Quad204 Project area
10.4.4 Total loss of hydrocarbon inventory from the FPSO In the highly unlikely event of a total loss of hydrocarbon inventory from all FPSO storage tanks, release of oil from a spill at the Quad204 FPSO indicates the movement of the slick to the east and north east of the release, and of Shetland, by prevailing winds and currents. Oil beaching (total estimated to be between 5197 – 19610 tonnes, i.e. between 3 - 11 % of the total) is most likely to occur on the west coast of Shetland, with stochastic modelling indicating that the oil will beach in a minimum time of 2.9 days (Figure 10.3). Under constant, 30 knot (15m/s) onshore winds as inputted into the deterministic model, beaching is likely to occur on Shetland in 2 days and 6 hours.
winds took the oil directly to shore and there was no intervention response, beaching could occur in Norway in 33 days, during the winter period. It should be noted that, under typical conditions (this refers to the most commonly occurring wind speeds and directions which occurred during the time periods for which wind data were available), it is predicted that oil is likely to reach the median line between Norway and the UK in 17 days, given the action of the prevailing currents and winds. During summer deterministic modelling beaching failed to occur within 40 days. The stochastic modelling shown in Figure 10.3 using real wind data is a more informative representation of possible beaching probabilities.
The potential for oil to reach Norway varied between 10 and 60% (Figure 10.3). If prevailing
Page 10.14
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Year 1
Year 2 – Worst Case
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Page 10.15
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Year 3
Figure 10.3: Probability of surface oiling and beaching locations from crude oil spill at the new FPSO without response (worst case scenario)
10.4.5 Total loss of diesel inventory from the FPSO Diesel is non persistent oil that is rapidly lost from the sea surface. Typically, a diesel spill may be expected to persist for approximately 8 hours after spillage. The impact of a diesel spill is expected to be restricted to the vicinity of the release point. The modelling scenarios outlined in Table 10.11 show that the surface slick would extend for a maximum distance of 37 km from the release point for a total loss of diesel inventory from the FPSO. The influence from south westerly winds during the winter results in the area potentially impacted by the surface slick. Figure 10.4 shows the probability of the extent of the area that could be impacted by a total inventory loss of diesel during summer months and winter months. No shoreline impacts are expected to arise even from total loss of containment of the diesel inventory.
10.4.6 Medium sized diesel spill from the FPSO As previously stated the impact of a diesel spill is Page 10.16
expected to be restricted to the vicinity of the release point, for this scenario, the FPSO. The scenario outlined in Table 10.11 shows that the surface slick would extend for a maximum distance of 29 km from the release point for a medium sized diesel spill. No shoreline impacts are expected to arise even from medium diesel spill.
10.5
Environmental vulnerability to oil spill
Environmental vulnerability to oil spill is a factor of both the likelihood of impact of an oil spill (as considered in previous sections) and the sensitivity of the environment. In a recent memorandum to the UK government regarding the Gulf of Mexico oil spill the JNCC has highlighted that the key implications are with respect to both the Government’s and the industry’s ability to understand and predict the environmental impacts of any oil spill. This is needed for both planning (to ensure the most appropriate response is available) and in responding should a spill occur (JNCC, UKD 06e). Offshore and coastal vulnerabilities need to be considered separately as different parameters will apply. November 2010
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Figure 10.4: Probability of surface oiling and beaching locations from total diesel inventory loss (summer and winter months). (Source: OSR, 2010)
10.5.1 Offshore Effects from a hydrocarbon release will largely be associated with the oil plumes. The impacts of an oil spill will be highly dependent on environmental sensitivities, prevailing sea state and weather conditions at the time. The sea and weather conditions in the Quad204 Project area (see
Chapter 4) mean minor spills will normally be broken up and dispersed rapidly. The JNCC has stated in a memorandum to the UK Parliament that the greatest risks to nature conservation of oil on the offshore (deepwater) sea surface are to seabirds (JNCC UKD 06). Seasonal vulnerability of birds to oil pollution within the vicinity of the Quad204 Project is presented in
Table 10.13: Block specific seabird vulnerability to surface pollution (JNCC, 1999)
November 2010
Page 10.17
Accidental Events Table 10.13 and is derived from the JNCC ‘offshore vulnerability index’. Seabird species at the Quad204 Project area are considered to be vulnerable to surface pollution during the months of March, May, June and September. For the rest of the year vulnerability is low (JNCC, 1999). The magnitude of any impact will depend on the number of birds present, the percentage of the population present, their vulnerability to oil spill and their recovery rates from oil pollution. One of the key concerns for surface oil is physical impacts upon seabirds. The oil can become incorporated into the feathers which can cause loss of insulation and waterproofing. If birds become heavily oiled their survival rates are lowered. There can also be impacts to plankton in the immediate area of the spill and for the duration of the spill release due to the solution of aromatic fractions into the water column. Any acute toxic
effects are not likely to be measurable in the medium to long-term after the release has stopped. Such effects will be greater during a period of plankton blooms and during fish spawning periods. Contamination of marine prey including plankton and small fish species may then lead to aromatic hydrocarbons accumulating in the food chain. These could have long-term chronic effects such as reduced fecundity and breeding failure on fish, bird and cetacean populations. This may affect fish stocks of commercially fished species and a major oil spill could also have a localised effect on the fishing industry, should certain areas be closed to fishing. Some commercially important species spawn in the vicinity of the Quad204 Project or use the wider area as a nursery ground (Figure 10.5 and Figure 10.6), although the immediate Quad204 Project area is not a spawning or nursery ground for many commercially fished species.
Figure 10.5: Spawning areas in the vicinity of the Quad204 Project (note: spawning periods are temporally restricted)
Page 10.18
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Accidental Events
Figure 10.6: Nursery areas in the vicinity of the Quad204 Project
Cetaceans are also present in the Quad204 offshore area. In the event of an oil spill, the amount of oil ingested or aspirated which is likely to cause harm will depend on the species and their feeding strategy, the overall health of individuals before ingestion or exposure, and the characteristics of the oil and volatile compounds. It is thought unlikely that a population of cetaceans in the open sea would be affected by an oil spill in the long-term (Geraci, 1990). Baleen whales are particularly vulnerable to oil while feeding, as oil may stick to the baleen while the whales "filter feed" near oil slicks. Many cetacean species exhibit seasonal migration patterns and return to feed in the same areas. Their strong attraction to specific areas for breeding or feeding may override any tendency to avoid the presence of oil. However, data on the effects of oil spills on cetaceans are limited and determining a causal relationship between exposure to oil or volatiles and detrimental effects on cetaceans is difficult. Schiehallion crude oil has a limited time window for effective dispersant application, although this can be extended by use of demulsifiers. Dispersant tests undertaken (IKU, 1995) identified the dispersant Dasic-Slickgone NS to be the most effective on spilled Schiehallion crude oil and this provided a rapid dispersion up to six hours after the spill in a ten knot wind at summer sea temperatures. The dispersant is still effective for
November 2010
several days after the spill, albeit at a slower rate. Water-in-oil emulsions formed by Schiehallion crude oil can be effectively broken down by demulsifier, with the oil residue liberated amenable to treatment by dispersant. Use of demulsifier with dispersant, may extend the time window of effective dispersant use by up to one or two days.
10.5.2 Coastal The likelihood of any oil spill having an impact on the coastal environment is: Likelihood of the oil spill occurring x Probability of that oil beaching The level of impact is also directly related to the volume of the oil released and the volume of emulsified oil beaching. As the toxic volatile components of the Schiehallion crude rapidly evaporate on entering the marine environment, the most likely impact of any oil spill will be one of physical smothering and coating by oil. For oil to beach on Shetland, a number of failures must occur (Figure 10.7). Overall probability of a major oil spill beaching on Shetland from Quad204 Project operations is therefore remote - extremely remote. However, the impact of such an event will be moderate – major (depending on the time of year and the extent of oiling along the coast).
Page 10.19
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Figure 10.7: Event tree analysis of likelihood of an oil spill beaching on Shetland from Quad204 operations
Orkney and Shetland are the closest landmasses to the proposed project and, in the unlikely event of an oil spill occurring, may be affected. Both island groups are comprised of a large number of islands and skerries with many coastal habitats being designated as sites of international, European and
Page 10.20
national importance (Table 10.14, Figure 10.8).
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Designation
Conservation interest Shetland
1 - Hermaness, Saxa Vord and Vallafield
SPA
Breeding seabirds – northern fulmar, northern gannet, great skua, common guillemot, Atlantic puffin and red-throated diver.
2 - Keen of Hamar
SAC
Calaminarian grasslands of the Violetalia calaminariae and calcareous and calcshist screes of the montane to alpine levels (Thlaspietea rotundifolii). Also contains European dry heaths.
3 - Ramna Stacks and Gruney
SPA
Breeding seabirds and supports one of only seven Leach’s petrel breeding sites in the UK.
4 - East Mires and Lumbister
SAC, SPA
Blanket bog
5 - Fetlar
SPA
Aggregations of breeding birds – Arctic Skua, Arctic tern, Dunlin, Fulmar, Great skua, Red-necked phalarope, whimbrel. Breeding bird assemblage.
6 - North Feltar
SAC
Fen, marsh and swamp. Dwarf shrub heath.
7 - Hascosay
SAC
Blanket bog. Also supports otters.
8 - Ronas Hill, North Roe and Tingon
SPA, SAC and Ramsar
Supports internationally important concentrations of seabirds. Representative example of blanket bog and heath habitats.
9 - Otterswick and Graveland
SPA
Aggregations of breeding birds – red-throated diver.
10 - Sullom Voe
SAC
Representative example of “large shallow inlet and bay”, “reefs” and presence of horse mussel beds.
11 - Yell Sound coast
SAC
Otters and harbour seals.
12 - Papa Stour
SPA, SAC
Considered as one of the best areas in the UK for reefs and sea caves. Important for Arctic tern, Arctic skua and ringed plover.
13 - The Vadills
SAC
Complex saline lagoon system.
14 - Foula
SPA
Supports breeding seabird populations. Also supports Leach’s petrel colony.
15 - Noss
SPA
Aggregations of breeding birds – fulmar, gannet, great skua, guillemot, kittiwake and puffin. Breeding bird assemblage.
16 - Fair Isle
SPA, SAC
Fair Isle wren endemic to island. Supports international populations of seabirds. Habitat types designated include heath and vegetated sea cliff communities.
17 - Mousa
SAC, SPA
Aggregations of breeding birds – arctic tern and storm petrel. Common seal, reefs and sea caves.
18 - Lochs of Spiggie and Brow
SPA
Icelandic whooper swan and wintering and breeding waterfowl.
19 - Sumburgh Head
SPA
Supports nationally important breeding population of Arctic tern and >20,000 individual breeding birds.
November 2010
Page 10.21
Accidental Events Site
Designation
Conservation interest Orkney
1 - West Westray
SPA
Breeding seabirds and flora.
2 - Papa Westray
SPA
Aggregations of breeding birds – arctic skua and arctic tern.
3 - Sanday
SAC
Harbour seal.
4 - East Sanday coast
SPA, Ramsar
Wintering waders – purple sandpiper, turnstone and harbour seal.
5 - Calf of Eday
SPA
>20,000 breeding seabirds, cormorant.
6 - Faray and the Holm of Faray
SAC
Grey seal.
7 - Rousay
SPA
1,000 pairs representing 2.3% of the breeding population of Arctic Tern in Great Britain. Supports >20,000 seabirds during the breeding season – guillemot, kittiwake, Arctic skua, fulmar, Arctic tern.
8 - Marwick Head
SPA
Seabirds – black-legged kittiwakes and common guillemot.
9 - Loch of Isbister
SAC
Natural eutrophic lakes with Magnopotamion or Hydrocharition-type vegetation. Also Transition mires and quaking bogs and otters.
10 - Orkney mainland moors
SPA
Aggregations of breeding birds – hen harrier, red-throated diver and shorteared owl. Aggregations of non-breeding birds – hen harrier.
11 - Stromness heaths and coast
SAC
Coastal heath, geology and morphology.
12 - Loch of Stenness
SAC
Freshwater plants, saline lagoon, wintering wildfowl.
13 - Auskerry
SPA
Aggregations of breeding birds – arctic skua and storm petrel.
14 - Hoy
SAC, SPA
Geology, geomorphology, >20,000 seabirds, wet and montane heath, petrifying tufa springs, woodland, moorland birds and upland heath.
15 - Copinsay
SPA
Aggregations of breeding birds –fulmar, great black-backed gull, guillemot and kittiwake. Breeding bird assemblage.
16 - Switha
SPA
Roosting barnacle geese.
17 - Pentland Firth Islands
SPA
Aggregations of breeding birds – arctic tern.
Table 10.14: Internationally important conservation areas in Orkney and Shetland (SNH, 2010)
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Figure 10.8: Designated sites on Orkney and Shetland
The following coastal sensitivities have been identified as being particularly vulnerable to oil spills: seabird populations; waders, divers and waterfowl; otters; seals; coastal habitat types; fishing; mariculture; tourism and amenity. Shetland The main coastal sensitivities to oil spills in Shetland are illustrated in Figure 10.9. Shetland has considerable lengths of cliff coastline, which support internationally and nationally important populations of breeding seabirds. In addition, shingle/rock and boulder shores on the western and northern coasts are important breeding sites for arctic tern (Sterna paradisaea) and ringed plover (Charadrius hiaticula). The coastline also has numerous boggy areas, which support approximately half of the British breeding population of red-throated diver and other moorland bird species. Approximately 22% of the UK’s harbour seal population occurs in Shetland and nationally important otter concentrations are present in Yell Sound. There are a number of seabird breeding colonies along the west coast of Shetland, as well as overwintering seaduck and resident seabird populations. Likely impacts arising from an oil spill will principally be from the physical smothering effects of oil and contamination and potential November 2010
degradation of habitats and feeding grounds. Oil spills are also potentially very damaging to commercial fisheries by excluding fishermen from fishing grounds for the period that oil is on the water, by the fouling of fishing gear and tainting of fish. These impacts are generally short-term and very localised for small spills, but impacts to fisheries can be long lasting for larger spills. When a spill occurs the public perception of the seafood value originating from the spill area can be lowered which can have a serious impact on market value. Fishing and mariculture are very important industries in Shetland. The most important inshore fishing grounds include St Magnus Bay for seine net fishing and coastal waters around the entire coastline for shellfish. Mariculture operations are important along the west coast of Shetland with salmon, mussels and oysters being cultivated (Figure 10.9). Oil spills may also have a direct impact on the amenity value of the coastline due to the physical and visual impact of oiling. This effect is generally short lived as a large proportion of the beached oil is broken down by natural means or mechanical removal. Perception of damage may be longer lived, particularly by potential tourists rather than the local population. The tourist industry represents a significant proportion of the local economy value with walking, ornithology, sailing, fishing, archaeology and diving being the most Page 10.23
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Figure 10.9: Coastal sensitivities to oil spill in Shetland
important. There are a number of tourist attractions on the west coast of Shetland, including houses, monuments and places of interest. There are also various water-based activities in this region with various leisure craft moorings and sea angling areas. Orkney and Northern Scotland Orkney comprises a large number of islands and skerries. To the north of the archipelago, the land is generally low lying, with sand and shingle beaches. Low, rocky shores and sandy beaches are of particular importance for wintering birds, including ringed plover, oystercatcher, dunlin, knot Page 10.24
and bar-tailed godwit. The west coast is characterised by dramatic cliff landscape and attracts internationally important breeding seabirds, with over 20 colonies holding more than 1% of a species total in the European Union. The north coast of Scotland is predominantly rugged and exposed with cliffs and steep rocky shores. Areas of intertidal sediment are limited to the upper reaches of sea lochs and isolated pocket beaches. The main coastal sensitivities to oil spills in Orkney and the north coast of mainland Scotland are illustrated in Figure 10.10. Common and grey seals breed on rocky shores November 2010
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Figure 10.10: Coastal sensitivities to oil spill in Orkney and Northern Scotland
throughout the Orkney islands. Grey seals are the most common with Orkney supporting over 32% of the UK grey seal pups. The northern coastline of Scotland is not considered as important for seal populations, although common seals and grey seals are known to be present in small numbers along this coast. Otters are also present around coastal areas, particularly those areas associated with freshwater pools or burns. Coastal fisheries surrounding Orkney are dominated by shellfish (creeling for lobsters and crabs, diving for scallops and scallop dredging), which occurs most abundantly in sheltered areas of the northern isles. Small-scale fisheries do also occur on west coast regions. Salmon farming in Orkney is a growing industry and is concentrated around the north isles and in Scapa Flow. Tourism is also a major industry in Orkney, attracting over 100,000 tourists per year. Tourist resources of the islands include natural history, archaeology, wildlife, maritime and wartime history. Orkney also has a World Heritage Site (WHS) November 2010
known as the Heart of Neolithic Orkney. The group of Noelithic monuments on Orkney consists of a large chambered tomb (Maes Howe), two ceremonial stone circles (the Stones of Stenness and the Ring of Brodgar) and a settlement (Skara Brae), together with a number of unexcavated burial, ceremonial and settlement sites. The group constitutes a major prehistoric cultural landscape which gives a graphic depiction of life in this remote archipelago in the far north of Scotland some 5,000 years ago. However given the distance from the Quad204 Project area there is no risk that this site is vulnerable to oil spill from Quad204. Creel boats dominate the inshore fishery, but there are also handlines, demersal gill nets, scallop divers and dredgers and Nephrops trawls. There is also an important commercial salmon and sea trout fishery in the area. Mariculture operations are limited along the northern coast of Scotland, with salmon farms only being found in Loch Eribol. Tourists are attracted to this area for the scenery and wildlife; however, numbers of visitors are generally lower than other areas of Scotland. Page 10.25
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10.6
Residual risks
zone
From the assessment undertaken, it can be seen that the most probable spills are spills of < 1 tonne from the Quad204 Project, which typically break down rapidly in the environment by weathering. Larger blowout spills and total loss of inventory from the FPSO that could reach the coastline are considered to be remote – extremely remote events, i.e. low probability.
h Other vessels within the 500 m safety zone
The consequences of a significant release of hydrocarbons from the Quad204 Project will vary depending on factors such as wind speed and direction and sea state, as well as the time of year and the length of coastline affected.
This existing Schiehallion OPEP will remain in force until the Schiehallion FPSO is removed from the field and the disconnection procedure for the current FPSO will be covered under the existing OPEP. Following this the OPEP will be revised to cover the installation and connection of the new FPSO and ongoing drilling operations will be included as Addenda to the OPEP.
Offshore concentrations of seabirds have variable vulnerability in the area and adjacent blocks throughout the course of the year, with many months identified as being of high vulnerability. The magnitude of any impacts to seabirds following on from a spill will depend upon the size of the spill and the weather conditions at the time and the number of birds present. There are also areas of very high vulnerability to the north and east (the most likely direction of travel) in April and June-August, and any large crude oil spill at the Quad204 Project field could pass through these areas. Although diesel has a high toxicity it rapidly disperses and diesel spills are not expected to pose any significant risks to offshore seabirds. Crude oil spills with a longer weathering window pose a risk of causing physical impacts and reducing the survivability of birds that come into contact with the spill. However the probability of large spills, such as an uncontrolled blowout, is considered remote – extremely remote, meaning that the overall risk of an oil spill from the Quad204 Project adversely impacting the coast of Scotland is assessed to be extremely low. BP has in place a range of response/mitigation measures to address such risks, as detailed in Section 10.7.
10.7
Oil spill response strategy
10.7.1 Offshore response Currently an Oil Pollution Emergency Plan (OPEP) is in place for the Schiehallion/Loyal development. The OPEP covers: h Schiehallion FPSO
h “In field” mobile drilling rigs drilling within licensed conditions, as described in Addenda to the OPEP. The OPEP details that the standby vessel, which stands off the installation at all times carries 5-10 tonnes of dispersant and spraying booms.
10.7.2 Coastal response Spills most likely to affect the Scottish coastline and inshore waters are large spills from blowouts and these spills have a low probability of occurrence (remote - extremely remote) and likely moderate-major consequence depending on time of year and length of coastline impacted. Following on from a large oil spill Shetland has a far greater risk of oil beaching than Orkney and the north coast of the Scottish mainland. Overall risk of oil spill impacting the Scottish coastline is minor. The BP Onshore Oil Spill Plan currently in place for the Schiehallion, Foinaven and Clair assets will also apply to the Quad204 Project. As part of this plan, BP have contracted OSRL to have strategically located mobile response packages, and trained response personnel, that can be engaged to combat oil spills approaching inshore areas. The packages are located on the Shetland mainland at Sullom Mine, Brae and on Yell at Cullivoe. They comprise a number of response trailers loaded with containment booms and ancillary booming support equipment. The contract arrangements extend to the provision of a pool of trained local responders who, if available, will activate the equipment (trailers) to a predetermined location and undertake deployment operations. The responders are sourced from local salmon and shellfish farmers and the local haulers who also provide vehicles for towing the trailers. The BP Onshore Oil Spill Plan will be reviewed and modified to incorporate any changes required for the inclusion of the Quad204 Project.
h Infield subsea flowlines and risers, including flowlines from the Loyal reservoir
10.7.3 Oil pollution emergency plans
h Shuttle tanker when inside the 500 m safety
It is expected that, in the unlikely event of a large
Page 10.26
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Accidental Events incident affecting significant areas of the Shetland shoreline, control of all resources will fall to the Local Authority operating under the auspices of the Shoreline Response Centre. A number of documents, developed in agreement/co-operation with relevant stakeholders detail how the response will be co-ordinated and managed (e.g. BP Atlantic Frontier Programme Shoreline Protection Strategy; BP/OSR Shetland Coastal Response Callout Strategy; Shetland Islands Council Marine Pollution Contingency Plan; Sullom Voe Harbour Oil Spill Plan.) BP is committed to doing everything in its power to clear up any spill regardless of the cost. In addition BP, as an offshore operator active in exploration and production on the UKCS is party to a voluntary oil pollution compensation scheme, the Offshore Pollution Liability Association (OPOL). OPOL members accept strict liability for pollution damage and the coast of remedial measures. These spill plans are regularly revised in line with regulatory requirements. In light of the Deepwater Horizon incident in the Gulf of Mexico, the Schiehallion Field OPEP and the MODU OPEP Addendum will consider the implications of well blowout and, where appropriate, will identify and put into action lessons learned in addition to already established procedures. The OPEP will be submitted for approval by the regulator in sufficient time to allow full consideration of the proposals.
10.7.4 Contingency planning BP has in place the resources necessary to provide a commensurate level of response to the size of spills they may encounter and are compliant with the requirements as detailed within the DECC OPRC guidance notes. The system is based upon the standard 3 Tiered system and is defined as follows:Tier 1: Monitoring and surveillance using infield vessels Tier 2: Additional aerial surveillance and dispersant spraying capability is available through OSRL Tier 3: A full Tier 3 capability is available through OSRL BP E&P UK are full members of Oil Spill Response, based in Southampton, who provide the full range of equipment and personnel necessary to fulfil the response expectations of BP E&P UK and to align with the regulatory requirements. Surface spill response will comply with UK Regulatory requirements including aerial November 2010
surveillance capability within four hours; dispersant spraying within 6 hours; and the high-rate dispersant application from the C130 Hercules within 9 hours. Natural dispersion by wave action is the preferred method of dispersion, but should any sensitive resources be threatened by surface oil, BP may engage dispersant application onto fresh oil. In practice such a decision would be made after consultation with the DECC, the Coastguard and the Scottish Environment Group which includes Marine Scotland, JNCC and SNH. In common with our other west of Shetland assets, standby vessels will also be equipped with dispersant capability. Given that oil spills could occur from a number of scenarios BP will have in place a variety of scenario plans to enhance response effectiveness and reduce response time. These will include consideration of pressure and flow monitoring equipment, backup BOP operation, intervention by suitably rated vessels and equipment, compatibility of BOP and Lower Marine Riser Package connectors with capping equipment.
10.8
Cumulative and transboundary risk
10.9
Cumulative risk
Other developments in the west of Shetland area from which a spill may occur include h The Foinaven FPSO is located within 12.3 km of the Schiehallion FPSO. The Foinaven field is operated by BP and oil is produced into the Foinaven FPSO facility which is permanently stationed in the field. The crude oil is exported by shuttle tankers to market and gas is exported via the WOSPS. h BP’s Clair Phase 1 and new Clair Ridge Development. The Clair Ridge Development is the second stage of the Clair oil field development, expanding on the Clair Phase 1 platform which started production in 2005. The Clair Ridge Development will involve the installation of two bridge-linked platforms, one supporting drilling and production and the other supporting accommodation and utilities, on the West of Shetland Continental Shelf in UKCS Block 206/8. The Clair Ridge oil export pipeline will tie into the existing Clair Phase 1 pipeline to Sullom Voe Terminal, Shetland and the gas export pipeline will tie into the existing West of Shetland Pipeline System. h The Laggan-Tormore Fields west of Shetland are being developed by Total to produce gas Page 10.27
Accidental Events condensate. This project incorporates several component parts, including the offshore subsea production system with the drilling of up to eight wells at the two fields, import flowlines, gas processing plant at Sullom Voe, and export pipeline to the Frigg UK Association (FUKA) pipeline. The fields are located 85-90 km west of Shetland, approximately 125 km from the BP operated onshore SVT. h The Solan Field located in the West of Shetland Continental Shelf approximately 135 km to the west south west of Shetland mainland is being developed by Chrysaor Limited from May 2010. The development will initially comprise a subsea horizontal production well incorporating duel electric submersible pumps and a subsea horizontal water injection well to provide additional pressure support. The wells will be tied back to a platform comprising a steel articulated tower and deck and a subsea storage tank, with a 300,000 barrel storage capacity. The platform will be not normally manned.
are in existence for dealing with international oil spill incidents with states bordering the UK. In the event of a major spill which is predicted to spread into Norwegian waters the NORBRIT plan will be activated. The NORBRIT plan is a joint UK/Norway oil spill contingency plan operating within the framework of the 2006 National Contingency Plans, the plan is oriented towards major spills. It becomes operational, when agreement to the request for its implementation is reached. Responsibility for implementing joint action rests with the Action Co-ordinating Authority (ACA) of the country on whose side of the median line a spill originated. The UK’s Counter Pollution Branch of the Maritime and Coastguard Agency (MCA) is the ACA for the UK. In the event of a major spill which is predicted to drift into Faroese waters the MCA will liaise with the Marine Rescue and Co-ordination Centre (MRCC) in Torshavn, Faroe.
10.11 Chemical spills
As indicated by historical data, the likelihood of one major spill occurring is remote or extremely remote, limiting the potential for cumulative oil spill impacts from the Quad204 Project and other existing installations. Detailed contingency plans are in place for each installation, outlining the response measures to be implemented in the event of any spill.
10.11.1 Chemical spill source identification
10.10 Transboundary risk
A Management System, which aligns with the North Sea SPU requirements, will be used to monitor and manage chemical storage, usage and disposal. This will be supported by an auditable chemical assessment and selection process.
Oil spill modelling undertaken (Section 10.4.1) for the Quad204 Project – which assumed no response measures were implemented – indicates some probability that in the event of a worse case oil spill a transboundary impact could result, with regard to Norwegian waters and coastline and to a lesser extent in Faroese waters. The assessment of spill likelihood in this chapter, based on historical UKCS and international incident data, demonstrates that the likelihood of a spill large enough to lead to such a transboundary impact is remote – extremely remote. Therefore BP believes that consultation under the Espoo convention is not required as a result of the Quad204 Project, The Espoo Convention requires notification and consultation only on projects likely to have a significant adverse environmental impact across boundaries. The risk of oil spill having a transboundary impact, particularly from the North Sea operations, is recognised by the UK Government and other governments around the North Sea. Agreements Page 10.28
A range of chemicals will be used on the Quad204 Project for drilling, process and utilities (see Chapter 7) and there is some risk of chemical spills, for example, during chemical transfer onto or within the installation.
10.11.2 Chemical spill prevention
Chemical spill equipment will be provided at strategic locations around the FPSO to enable operational personnel to treat any chemical spills. Installation and supply vessel personnel will be given full training in chemical spill prevention and actions to be taken in the event of a spill. A system will be in place for the reporting of all spills. Examples of measures for minimising the risk of chemical spills are provided below. h A centralised chemical injection area will be used for injection skids to reduce spill risk areas on FPSO. h Bunding will be designed around areas identified as potential chemical spill sources, including chemical injection pumps and tote tanks. Contained fluids will be shipped to shore for disposal. The bunded areas for the tote tanks are sized to contain at least 110% of the November 2010
Accidental Events largest container and removable plugs will be included in the drain boxes associated with the bunds to enable operations personnel to collect any chemical spillages.
10.11.3 Residual risk As for oil spills, BP’s target is for zero chemical spills. However, despite design, operational and training measures to reduce the probability of chemical spill, there remains a risk. To reduce the potential chemical spill risk from chemicals used offshore, BP continually works with its chemical suppliers to ensure that chemical use is minimised, wherever possible, without compromising technical performance. Furthermore BP recognises that substitution is an important part of the OSPAR Harmonised Mandatory Control Scheme (HCMS) and is committed to the investigation of alternative components and products. Information on specific chemical use and associated environmental impact assessment will be provided in the relevant PONs prior to the commencement of activity. Given the high energy marine environment of the wider Quad204 Project area, any chemical spill is expected to rapidly disperse in the offshore marine environment with a possible negligible to minor localised impact on plankton or fish egg/larvae, depending on the season. In addition the low probability of a chemical spill occurring with any significant associated environmental impact, the residual risk of chemical spill during the Quad204 Project will be remote.
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Accidental Events
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Waste
11 Waste The environmental issues associated with those wastes which could potentially have an impact on the marine environment or the atmosphere, e.g. drilling discharges and atmospheric emissions, have been addressed in previous chapters of this ES. Other waste material generated during offshore activities will be returned to shore. This chapter describes the typical types of waste likely to be generated and the management procedures that will be in place to minimise, handle and dispose of waste from the Quad204 Project.
11.1 Introduction The vast majority of wastes generated are as a direct result of oil and gas production and processing. Waste will be generated during all phases of the project: drilling, installation, hook-up and commissioning and operations. This chapter describes the handling and disposal of OBM cuttings, which cannot be discharged to sea; and non-hazardous and hazardous operational waste from the FPSO. Wastes from installation and support vessels are not expected to be significant and will be taken onshore for disposal unless allowed by the Merchant Shipping Regulations for overboard discharge. Surplus chemicals will be returned to vendors and are also not discussed further in this chapter.
11.2 Regulatory control Disposal of waste streams generated from the Quad204 Project will be managed in accordance with the requirements of the following key environmental legislation and standards: h The Merchant Shipping (Prevention of Pollution by Sewage and Garbage from Ships) Regulations 2008. These prohibit the disposal of garbage (including plastics) and galley waste (except ground food wastes) overboard. Waste offshore is therefore collected for disposal or recycling onshore. All waste for disposal onshore must have accurate descriptions and appropriate segregation measures in place in order to ensure legal onshore disposal at appropriate licensed sites through properly licensed waste disposal contractors. h The Environmental Protection Act 1990 governs the onshore disposal of waste in the UK and is implemented by the Scottish Environment Protection Agency (SEPA) in Scotland. Although this act provides no direct offshore November 2010
control, its requirements for onshore waste disposal indirectly makes provisions for the handling of waste offshore prior to shipping to shore for disposal. h Environmental Emissions Monitoring System (EEMS) guide for data submission – Oil and Gas UK. Environmental emissions are either directly measured or estimated, and reported to DECC. In turn, DECC uses these environmental returns for government reporting requirements. h The Waste Framework Directive (WFD – Council Directive 2006/12/EC). This establishes the requirements for management of wastes across the EU. The requirements of the WFD are implemented in the UK through a suite of onshore waste management legislation. Waste is classed as “Controlled Waste” if it has controls placed over its handling and disposal under UK waste legislation. Controlled waste includes both non-hazardous and hazardous (including special) waste. Hazardous wastes can be defined as substances which, due to their physical and chemical characteristics, can result in potential harm to human health or the environment when released to and dispersed through the air, land or water. No mixing of nonhazardous and hazardous waste is allowed. h The National Waste Strategy of Scotland sets out key principles for engaging with statutory objectives for waste management: h Waste should be prevented or reduced at source as far as possible (e.g. waste is designed out or packaging is reduced and the correct amount of materials are ordered) h Where waste cannot be prevented, waste should be reused or refurbished and then reused as far as possible h Waste materials should be recycled or reprocessed into a form that allows them to be reclaimed as a secondary raw material h Where useful secondary materials cannot be reclaimed, the energy content of waste should be recovered and used as a substitute for non-renewable energy sources BP is under a ‘Duty of Care’ to ensure that it handles all of its controlled waste safely and in compliance with the appropriate regulations. A fundamental aspect of the Duty of Care requires BP to make sure that any organisation collecting, transporting or receiving BP waste has the required authorisation to do so. Appropriate documentation or Consignment Notes must accompany all waste to ensure it is properly Page 11.1
Waste identified for subsequent appropriate handling, treatment and disposal.
11.3 Waste management policy Waste management is one of the most significant environmental challenges facing the oil and gas industry as the materials consumed in the production of oil and gas generate a wide range of wastes. BP is committed to reducing waste production and to managing all produced waste by applying approved and practical methods. This commitment is consistent with BP’s aim to reduce the impact of its operations on the environment, and is in accordance with the waste management hierarchy illustrated in Figure 11.1. Only if waste cannot be prevented, reclaimed or recovered, should it be disposed of.
Historic data from the existing Schiehallion FPSO for 2005 to 2009 indicates that most of the waste that is generated offshore is recycled, sent to landfill, discharged under consent or reused (Figure 11.2). The greatest proportion of waste is sent for recycling. Scrap metal, wood, plastic and other material equate to 48% of total average waste produced between 2005 and 2009. Discharge under consent Incineration 12.7% 0.2% Waste to energy Treatment 0.1% 3.2%
Landfill 34.7%
Reuse 1.5%
Recycling 47.7%
Figure 11.2: Disposal routes for Schiehallion FPSO waste (average of years 2005 to 2009)
11.4 Waste generation 11.4.1 Waste types and disposal routes Waste likely to be generated during the lifetime of the Quad204 Project includes both non-hazardous and hazardous wastes and is summarised in Table 11.1.
Non-hazardous waste
Hazardous waste
Domestic waste
OBM cuttings
Glass
OBM or reservoir hydrocarbon contaminated fluids
Aluminium and tin cans Cardboard, packaging and paper
Waste oil and sludges Oily rags
Scrap metal
Waste chemicals
Wooden pallets
Paint tins, chemical sacks, chemical/oil drums
Plastic
Sand blasting grit Welding wastes Batteries and electrical equipment Medical waste
Table 11.1: Summary of waste types likely to be produced by the Quad204 Project
Page 11.2
100% Percentage of total waste (%)
Figure 11.1: Waste management hierarchy
The quantity of recycled waste has increased gradually year on year, from 140 tonnes in 2005 to 244 tonnes in 2009. In 2008 recycling represented 63% of the total waste disposed (Figure 11.3). Although the total quantity of waste to landfill has fluctuated from approximately 127 tonnes in 2005 to 139 tonnes in 2009, with a dip to 92 tonnes in 2008, the overall percentage of waste going to landfill compared to other disposal routes has gradually decreased representing only 28% of the total waste disposed in 2009 compared to 45% in 2005. The quantity of reused waste has also fluctuated, although there has been little change in the total quantity of reused waste in 2005 when compared to 2009 figures. Drilling rigs and installation vessels send similar percentages for recycling. Similar waste figures are anticipated for the Quad204 FPSO.
80% 60% 40% 20% 0% 2005
2006
2007
2008
2009
Year Landfill Reuse Incineration Treatment
Recycling Waste to energy Discharge under consent
Figure 11.3: Overall breakdown of waste disposal routes
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Waste 11.4.3 FPSO operational waste
for the Schiehallion FPSO from 2005 to 2009
As the new Quad204 FPSO will be larger than the current Schiehallion FPSO, the amount of total waste generated may increase. However, efforts will continue to minimise waste and reduce the percentage of waste being disposed of in landfill, and encourage recycling/reuse initiatives. Waste figures can vary considerably from year to year depending on maintenance activities and other routine and non-routine activities. Figure 11.4 and Figure 11.5 provide average percentages of nonhazardous and hazardous waste types generated at the Schiehallion FPSO from 2005 to 2009.
11.4.2 Drilling waste (OBM cuttings) The largest volume of waste potentially generated during the Quad204 Project is likely to be OBM cuttings. OBM may be used for drilling the lower sections of the Quad204 wells. Based on the well programme presented in Section 3.2 the total amount of OBM cuttings that may be produced between 2014 and 2021 is approximately 9,075 tonnes with the peak amount being 1,815 tonnes in 2017 (Table 11.2). It should be noted that all drilling may be undertaken with WBM in which case the WBM cuttings would be discharged to sea, therefore the figures presented in Table 11.2 are worst-case.
Sludges and liquids 1%
General w aste 36%
Drums/containers 3%
OBM cuttings will be contained and shipped to shore for disposal although alternative disposal options continue to be assessed such as offshore cuttings treatment technology (see Section 2.5), with the medium to long-term aim of reducing disposal of OBM cuttings to landfill. Segregated recyclables 20%
When OBM cuttings are shipped to shore, the chosen waste contractor will thermally treat the cuttings. Any oil that is separated out from the cuttings may be used on-site as an energy source for the site process; any excess oil will be stored for onward transportation to oil recyclers. Any resulting process water will be used to dampen the dry cuttings before final disposal at a landfill site. Samples of oil, water and the dry cuttings will be taken before onward transportation. The cleaned drill cuttings that will be disposed of to landfill will be used for covering other material that has been disposed of at the landfill site.
Scrap metal 40%
Figure 11.4: Schiehallion FPSO non-hazardous waste types (average of years 2005 to 2009)
Although scrap metal represents 40% of the total non-hazardous waste generated on the Schiehallion FPSO (Figure 11.5) all scrap metal is sent for recycling. The majority of drums and containers are also reused.
BPEOs for drill cuttings management have been undertaken within BP and the results of these together with lessons learned from Schiehallion drilling activities will be taken into consideration during the Quad 204 Project.
Section
Note 1
OBM cuttings per section per well (tonnes)
Forecast no. of wells
Year 2014
2015
2016
2017
2018
2019
2020
2021
Total
3
3
3
5
4
3
3
1
25
12¼"
274
822
822
822
1,370
1,096
822
822
274
6850
8¼"
89
267
267
267
445
356
267
267
89
2225
1,089
1,089
1,089
1,815
1,452
1,089
1,089
363
9075
Total (tonnes)
Note 1: All drilling may be undertaken with WBM Table 11.2: Projected OBM cuttings for disposal per year
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Page 11.3
Waste
Chemicals 6%
Paints 1%
Drums/containers 1% Oil 11%
h BP will develop a Waste Management Plan (WMP) for the Quad204 Project which will provide a structure for waste guidance and disposal at all stages during the project. h The WMP will identify: h The types of waste that will be generated
Sludges and liquids 63%
Miscellaneous special w aste 18%
Figure 11.5: Schiehallion FPSO hazardous waste types (average of years 2005 to 2009)
11.5
Quad204 waste management strategy
In line with BP’s waste management policy described in Section 11.3, all efforts will be made to reduce waste at source and to focus on reuse/recycling options for waste generated during the Quad204 Project. Waste management considerations have been incorporated into the design of the new FPSO as follows: h Recovered oil - as described in Section 3.6.11 open drains will be directed to the slops tanks. A skimming pump will remove oil forming on the surface of the slops tank and route this back into the process and finally to the oil cargo tank. h Helifuel samples - samples will be returned to the helifuel tank rather than sent onshore for disposal. h Oily sludges - the options for the disposal and removal of oily sludges will depend on their origin. Any residues that cannot be re-directed to process for treatment will be contained and then shipped onshore for safe disposal. h Maintenance – spares for routine maintenance items will be held at the aft end of the FPSO in a designated storage area. Maintenance activity will take place within a designated area which will help to minimise the generation of associated waste on decks. Cranes will be used to lift equipment from deck areas to the designated maintenance area. h Waste management station – there will be a designated waste management station at the aft end of the FPSO. This area will contain waste compactors and colour coded waste segregation units. h Accommodation area - dedicated waste collection/disposal areas will be allocated in the accommodation area. Page 11.4
h How all identified wastes will be managed as per the waste hierarchy h Waste contractors to be used to ensure waste is correctly documented, transported, processed and disposed of in an environmentally responsible manner and in compliance will all legislation h Regular audit programme to verify implementation of the plan Waste handling and disposal during drilling and SURF installation will be the responsibility of the contractor and will be covered by specific BP contractual conditions. The duty of care placed on BP regarding waste will be implemented through the use of bridging documents and premobilisation audits. The new FPSO will be commissioned onshore and will contain no waste materials once it leaves the shipyard. Waste will also be kept to a minimum during the tow of the FPSO from the shipyard to the field. Detailed waste management procedures will be developed prior to the operational stage using as a basis the procedures that are currently in place on the Schiehallion FPSO and the BP North Sea Strategic Performance Unit (SPU). The main objective of the waste management system during operations will be to ensure all wastes generated are: h Reduced to as low as reasonably practicable h Disposed of in a manner that complies with regulatory and BP’s Group Defined Practice (GDP) requirements and that does not harm people or result in a significant impact to the environment BP will ensure that all waste is transferred to an appropriately licensed carrier who has a Waste Carrier Registration / Waste Management Licence or Exemption. None of the wastes generated from the Quad204 Project are anticipated to pose any unusual handling or disposal issues. Potential cumulative impacts will be emissions from the use of skip and ship vessels used to transport OBM cuttings onshore for treatment and November 2010
Waste disposal (see Chapter 9) and the use of landfill for the disposal of waste generated offshore. Only appropriately licensed waste management contractors will be used therefore cumulative impacts are considered unlikely. All waste streams associated with the Quad204 Project will be shipped to shore for disposal or further use within the UK. This effectively removes the likelihood of any transboundary impacts.
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Page 11.5
Waste
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Environmental Management
12 Environmental Management This chapter provides information on BP’s environmental policy and management processes, how they are applied to the Quad204 Project and how they will be implemented during the operational phase of the development.
12.1
Quad204 Project environmental management and commitments
BP has recently developed the Environment Group Defined Practice (GDP) which is applied to the Quad204 Project. The Environment GDP defines BP’s approach to achieving consistently environmentally sound operations in new projects, and consists of two components: h Environmental Impact Management Process (EIMP) h Environmental Performance Requirements (EPRs) The EIMP seeks to identify and understand the Project’s environmental impacts. The EPRs define the criteria that BP shall meet in order to achieve a consistent delivery of environmental performance and address the twelve aspects illustrated in Figure 12.1. It should be noted that the performance
standards set out in the EPRs are not intended to replace legislative requirements; rather they are intended to complement and where relevant build on these requirements to ensure a consistent minimum standard of environmental performance across the BP Group as a whole. In the event of conflict between national law and EPRs, national law will prevail. The BP EPRs specify standards to be applied throughout the Quad204 Project. During the ENVID process (Section 5.4) the EPRs of potential relevance were identified for incorporation into the EIA and the Quad204 environmental management processes. Quad204 Project specific EPRs were developed based on the BP EPRs and these are presented in Appendix B. As per the requirements of the GDP, environmental impact assessment for the Quad204 Project, including consultation with stakeholders is an ongoing process through concept selection, front end engineering design and detailed design and onwards into project execution (see Chapter 5). A set of Quad204 Project HSSE goals were developed at the start of the project that incorporate the environmental aspirations of the project and these are outlined in Figure 12.2.
Figure 12.1: Summary of the BP Environment Group Defined Practice (GDP)
November 2010
Page 12.1
Environmental Management commitments for the Quad204 Project that go beyond regulatory standards are highlighted in the register. The commitments register will be updated as each element of the project continues into the execution and subsequent operational phases. Mitigation measures identified and commitments made will also be embedded into the following documents to ensure appropriate execution and management: h Project basis of design h Detailed engineering specifications h Contracts h Execution plans Each commitment will be assigned an owner within the Quad204 Project team, and will be reviewed periodically to ensure that it is being met. During implementation of the project, objectives and targets will also be used to set goals for continuous improvement in performance. In this way, environmental management is an ongoing process; it will continue beyond implementation of the mitigation measures identified during this EIA in order to strive for continuous improvement and to meet changing regulatory requirements.
12.2
The BP environmental management process
BP operates a unified management system to reduce HSSE risks and provide continuous improvement in quality of operations. BP’s HSSE management system ‘Getting HSSE Right’ (GHSSER) has been replaced by the ‘Operating Management System’ (OMS) in a phased approach; the North Sea SPU has implemented OMS in 2010. The OMS applies across the BP Group in support of the BP goals of “no accidents, no harm to people and no damage to the environment”.
Figure 12.2: Quad204 Project HSSE goals
A commitments register (see Appendix E) has been developed for each aspect of the Quad204 Project. The commitments register summarises the Quad204 Project management and mitigation measures identified during the EIA process. The key
Page 12.2
The OMS framework (Figure 12.3) applies the performance improvement cycle to local business processes. This delivers the BP Group requirements, for example the BP Environment GDP, which is categorised against the elements of operating. In turn, assessments against the BP Group requirements inform the risk assessment and prioritisation step of the performance improvement cycle to deliver safe, reliable and responsible operations.
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Environmental Management
Figure 12.3: BP operating management system framework
The requirements of the BP OMS are implemented in the North Sea Strategic Performance Unit (SPU) with a Local Operating Management System (LOMS) which incorporates UK legal requirements and corporate standards. Implementation of common SPU operating processes, practices and procedures seeks to drive a standardised way of managing HSSE and integrity risks and to share best practice. Within the LOMS for example, the BP North Sea SPU Environmental Management System (EMS) is certified to International Standards Organisation (ISO) 14001 requirements. Once operational, the Quad204 development will be managed in accordance with the scope of the LOMS and the North Sea SPU EMS.
12.3
Environmentally critical equipment
Environmentally Critical Equipment (ECE) is any equipment, the failure of which could give rise to unacceptable environmental performance such as: h Unplanned or uncontrolled release to the November 2010
environment h Regulatory non-compliance h Failure to meet a performance standard or target (i.e. failure to achieve continuous improvement in performance) During the Quad204 Project, prior to operations, ECE identification is being facilitated by the EIA matrices. The protective systems associated with the ECE will be identified and the planned maintenance routines for ECE assessed for adequacy. This information will be transferred to operations to ensure that ECE is operated and maintained to a level that achieves objectives and targets, complies with environmental consents and minimises adverse risk to the environment.
12.4
Environmental monitoring
Monitoring is an important activity for ensuring performance against the environmental regulatory and corporate requirements and is directly linked to the goals and improvement programmes specifically designed for the project. Monitoring enables the assessment of progress against goals as well as Page 12.3
Environmental Management gathering of information to track overall environmental performance.
system which includes a range of environmental awareness modules.
There are three inter-related drivers for such monitoring:
BP also requires training for all contractors involved in field operations. Contractors are audited and monitored to ensure that they have systems and controls in place to manage their environmental responsibilities.
h Statutory requirements e.g. chemical use and discharge h Corporate and project expectations and targets h Validation of predictions made in the EIA process Monitoring falls into two broad categories: performance monitoring and environmental effects monitoring. Performance monitoring involves the monitoring of emissions, effluents and waste generation. This measuring of environmental performance is required for a number of different purposes: h Monitoring data for compliance with environmental consents and regulatory requirements h Environmental data required by the DECC/Oil and Gas UK Environmental Emissions Monitoring System (EEMS) h To track performance against established objectives and targets set in the Environmental Aspects Register Performance measurement for the project will include: h Chemical use and dosing rates of chemicals h Drilling mud use h Oil-in-water levels h Atmospheric emissions h Waste generation h Spill of oil or chemicals Environmental effects monitoring will focus on seabed and benthos recovery following drilling and flowline installation operations (Chapter 6) and a West of Shetland noise programme (Chapter 8).
12.5
Environmental awareness and training
Trained and knowledgeable staff can help to prevent or reduce the effects of a pollution incident. As per the requirements of ISO 14001, all personnel who perform or manage project work that may have a significant impact on the environment must be trained. Detailed training records are maintained of all operational personnel against required environmental competencies. Essential HSSE training is managed by the BP HSSE competency Page 12.4
To ensure that on-site project personnel understand the part they play in contributing to environmental protection, BP provides training to help raise environmental awareness. Training is delivered through a range of techniques: toolbox talks, poster campaigns, E-learning and formal courses with hands-on techniques (e.g. spill response). Once operational, the FPSO’s standard induction for all personnel arriving onboard will contain an environmental component, incorporating issues which include, but are not limited to, spill prevention, waste and chemical management on the FPSO.
12.6
Interface with contractors
Contractor management is an integral part of the Quad204 Project and contractors working for BP are expected to demonstrate a high level of HSSE commitment and to have systems in place for managing HSSE. BP practices an assurance process that will verify the environmental management systems and processes adopted by all project contractors, including those contracted to complete offsite fabrication in order that all key contractors meet the intent of ISO 14001 as relevant to their activities. Pre-mobilisation audits (and provision of bridging documentation) of the drilling rigs and installation vessels is undertaken to ensure appropriate procedures, documentation and equipment is in place in order to meet measures identified during the EIA process, BP’s requirements and statutory obligations. Commitments, objectives and targets set for the Quad204 Project will be communicated to contractors, and contractor performance monitored. At the project level all offshore contractors involved in the installation of facilities must produce procedures for all aspects of the installation. Appropriate measures are introduced where necessary to ensure acceptable levels of safety and environmental protection. All offshore contractors are responsible for all aspects of national and international regulatory compliance with regard to their vessels, including pollution prevention measures.
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Conclusions
13 Conclusions This chapter outlines the key findings of the EIA process. Throughout the conceptual and FEED stages of the project considerable efforts have been made to remove or significantly reduce issues that could lead to possible impacts on the environment. Where this has not been possible, detailed attention has been given to defining ‘residual’ issues and seeking ways of minimising any potential impacts.
13.1
Approach
Environmental considerations have played an important role in the decision-making process throughout the Quad204 Project, and will continue to do so during detailed design, installation, commissioning and operational activities. The methodology that has been used to identify and assess the potential impacts resulting from the Quad204 Project can be summarised by the following steps: h Identification of the key environmental issues associated with the proposed development, using ENVID and feedback from informal consultations h Identification of mitigation measures including design solutions and management control measures that will eliminate or limit negative environmental effects h Detailed evaluation of each of the key issues and determination of the significance of the residual impacts Central to the above methodology was that, for all identified potential environmental issues, the following prioritised approach was followed: h Remove the issue by design; or, if that was not possible h Reduce the issue by design and/or defining operational targets; then h React to residual issues, by defining required mitigation The EIA has assessed both scientifically demonstrable risks to the environment and stakeholder concerns. In some cases, for example where there are project decisions still to be made, it has been considered prudent to assess what is perceived to be the worst-case scenario from an environmental perspective.
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13.2
Potential environmental issues
The following environmental issues were identified during the EIA process as the key issues associated with the Quad204 Project that might present a threat to the receiving environment: h Physical presence - the seabed and fauna within the vicinity of the Quad204 Project might be affected by the anchoring of the drilling rig, and the replacement/installation and presence of the FPSO and SURF infrastructure. In addition, offshore activities associated with all stages of the project and the physical presence of vessels, the FPSO and SURF infrastructure, could interact with other users operating within the same marine area h Discharges to sea - the seabed, fauna and water column in the vicinity of the Quad204 Project might be affected by discharges associated with drilling, commissioning, production and decommissioning operations. A number of these discharges were considered to have a negligible potential for adverse environmental impact, such as those derived from vessels (drainage, grey water and black water (sewage) discharges) h Underwater noise - sources of underwater noise generation from activities associated with the Quad204 Project include drilling, seismic survey, SURF infrastructure installation, pile driving, vessel movements and FPSO presence. These activities have the potential to impact upon marine animals in the vicinity of the project h Atmospheric emissions - air quality might be impacted by atmospheric emissions associated with drilling and production operations h Accidental events - the water column, coastal areas and associated fauna may potentially be affected by the accidental release of oil and/or chemicals. Oil can potentially be released from drilling and production operations, from flowlines and from vessel activity. A range of chemicals will be used for the Quad204 Project and there is some risk of chemical spills, for example during chemical transfer onto or within the FPSO. BP’s aim is to cause no damage to the environment, minimising the risk of spills using measures related to plant, people and processes h Waste - sources of waste generation from Quad204 Project activities include drilling and production operations. Impacts from these activities include atmospheric emissions from Page 13.1
Conclusions transport of waste to shore and energy/resource use associated with the onshore treatment and disposal of these wastes Overall, it is considered that following application of management and mitigation measures, the Quad204 Project will not cause any significant environmental impacts. For each of the issues above, detailed management and mitigation measures have been identified and reported in Chapters 6 to 11.
13.3
Issues removed or reduced by design
During conceptual design and FEED stages of the project many key decisions were made, leading to removal or major reduction in activities considered likely to have significant impacts on the environment and improvements in operating efficiency when compared to the previous vessel. These are presented in detail in Chapter 2. Key environmental design decisions include: h Atmospheric emissions h The selection of a centralised electrical power generation system allows for the recovery of waste heat from the turbine exhausts which is used for process heating requirements, removing the need for separate fired heaters or large electrical heaters. It also offers a high degree of operational flexibility coupled with high uptime, high efficiency and relatively low CO2 emissions when compared to a direct drive option h The flaring philosophy for the Quad204 Project is not to flare gas routinely during normal operations, and to have a closed flare system with flare gas recovery in order to reduce atmospheric emissions such as CO2, NOx, SOx and unburned hydrocarbons h VOC emissions will be reduced by the use of hydrocarbon gas blanketing in the crude oil storage tanks, which is recycled back to the process; and the use of shuttle tankers with VOC recovery systems during tanker offloading operations h Discharges to sea h Produced water and its associated chemicals will be routinely re-injected into the reservoir, thus significantly reducing potential impacts on the water column
Page 13.2
13.4
Key residual issues
As presented in Section 13.2 it is considered that the Quad204 Project will not have any significant environmental impacts. However, there are aspects of the project that will need to be managed sensitively in order to minimise potential environmental effects. These include the following key residual issues: h Underwater noise – pile driving is seen as the Quad204 Project activity generating the highest underwater noise levels that may have potential impacts on marine mammals. BP will implement a number of measures to mitigate noise impacts based on the principles of the JNCC guidelines for piling activities that are likely to eliminate the potential for injury and reduce non-trivial disturbance. Pile driving noise will be emitted over a short period of time and significant negative injury or disturbance impacts occurring as a result of the piling activities are considered unlikely. Seismic operations could also potentially have an impact on marine mammals. However, the worst case sound source level is expected to be lower than that anticipated during piling. Each individual seismic operation will be subject to a specific environmental assessment through the PON14 application process. The long term presence of vessel noise also needs consideration. Some operational noise sources such as FPSO and shuttle tanker thrusters will be intermittent but will continue for field life, and along with other noise sources will contribute to a noise ‘footprint’ at the location for field life. h Risk of oil spills – the focus of the Quad204 Project has been on spill prevention (from small operational spills to larger accidental spills such as blowout and total loss of FPSO oil storage cargo). The highlighted prevention methods will considerably reduce the risk of oil spill. However, a residual risk remains and therefore an oil spill response strategy has been developed. This strategy will be detailed in the OPEP which will include further consultation with the statutory authorities and appraisal of existing response arrangements.
13.5
Cumulative and transboundary impacts
The cumulative impact assessment has drawn on the SEA undertaken by DECC for the area north and west of Orkney and Shetland (SEA 4) (DTI, 2003). This SEA considered existing and longterm potential development in the area and therefore provides a basis for considering November 2010
Conclusions Quad204 Project’s input to long-term cumulative impacts in the area. Effects are considered cumulative if: h The physical contamination or “footprint” overlaps with that of adjacent activities; or h The effects of multiple sources clearly act on a single receptor or resource (for example a fish stock or seabird population) A review of the potential impacts associated with the Quad204 Project, and the mitigation measures proposed, indicates that no significant cumulative impacts are anticipated. Transboundary impacts originate in one country but have an effect on the environment in another country. A review of each of the potential impacts associated with the Quad204 Project and the mitigation measures proposed, indicates that no significant transboundary impacts are anticipated.
operations (e.g. piling operations) associated with the Quad204 Project may cause an injury or disturbance offence to any species designated as an EPS. This assessment concluded that the nature of the piling and the mitigation measures that will be put in place mean there will be a negligible risk of injury or disturbance offence as a result of these activities. There are a number of coastal conservation areas in Shetland and Orkney that have been designated under the EU Habitats Directive as SACs and under the EU Birds Directive as SPAs. It is not considered that there is likely to be a significant effect on any SPA, SAC or other European site or possible site arising from the Quad204 Project due to its remote location far from any such area.
13.7
Environmental management
The results of oil spill modelling (which assumed no response measures were implemented) indicates some probability that, in the event of a worst case spill, oil could move across international boundaries, particularly into Norwegian waters. The assessment of spill likelihood demonstrates a low probability of a spill large enough to lead to such a transboundary impact. Therefore BP believes that consultation under the Espoo convention is not required as a result of the Quad204 Project, the Espoo convention requiring notification only on projects likely to have a significant adverse environmental impact across boundaries.
BP’s Environmental Management System, as applied to the Quad204 Project, will incorporate the management and mitigation measures identified in this ES for implementation in the detailed design, installation and operational phases of the Quad204 Project. It will also implement effective monitoring and reporting of emissions and discharges. Project-specific commitments are described in Appendix E and they will also be incorporated into and implemented by BP’s management systems. The key commitments are highlighted in Appendix E.
13.6
Based on the findings of the Quad204 Project EIA process and the identification and subsequent application of the mitigation measures identified for each potentially significant environmental impact, it is concluded that the Quad204 Project will not result in any significant environmental impacts.
Protected areas and species
No significant impacts are expected upon the marine species and habitats protected by Annexes I and II of the Habitats Directive (as transposed to UK waters) and Annex I of the Birds Directive. The presence of protected species under Annex I of the Birds Directive is limited to European storm petrels. The European storm petrel is present in the area in high densities during September and occurs in internationally important numbers. The presence of protected species under Annex II of the Habitats Directive within the Quad204 Project area is limited to marine mammal species. Marine mammal species that may be found in the Quad204 Project area occur in relatively low densities or occur only occasionally or are casual visitors; furthermore mitigation measures are in place to minimise noise impacts from the project. BP has assessed whether the noise-emitting November 2010
13.8
Final remarks
Carrying forward the findings and recommendations of this EIA through formal commitments (Appendix E) will provide a transparent and auditable means of verifying that the measures identified are being delivered through BP’s externally verified environmental management system.
Page 13.3
Conclusions
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Page 13.4
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Miller PJO, Johnson MP, Madesn PT, Biassoni N, Quero M and Tyack P (2009). Using at-sea experiments to study the effects of airguns on the foraging behavior of sperm whales in the Gulf of Mexico. Deep Sea Research Part I: Oceanographic Research Papers, 56(7), 1168 – 1181. Muus BJ and Neilsen JG (1999). Sea Fish. Scandinavian Fishing Year Book, Hedehusene. NCC (1991). Atlas of nature conservations site in Great Britain sensitive to coastal oil pollution. Nature Conservancy Council, Peterborough. Nedwell JR, Edwards B and Needham K (2002). 'Noise measurements during pipeline laying operations around the Shetland Islands for the Magnus EOR project'. Subacoustech Ltd. Report No. 473R0212. Nedwell J and Howell D (2004). A review of offshore windfarm related underwater noise. Report by Subacoustech Ltd, Southampton, to The Crown Estate, London. Report No. 544 R 0308. Nedwell, J.R., Edwards, B., Turnpenny, A.W.H., and Gordon, J, (2004) Fish and marine mammal audiograms: A summary of available information. Subacoustech report ref: 534R0214. Available online at: http://www.subacoustech.com/information/downloa ds/reports/534R0214.pdf [Accessed 18/11/2010]. Nedwell, J.R, S.J Parvin, B Edwards, R Workman, A.G Brooker, and Kynoch J.E (2007). Measurement and interpretation of underwater noise during construction and operation of offshore windfarms in UK waters. Report for COWRIE, Subacoustech. Neff JM, Hillman RE and Waugh JJ (1989). Bioaccumulation of trace metals from drilling mud barite by benthic animals. In Engelhardt F.R., Ray J.P. & Gillam A.H. (eds.) Drilling Wastes. Proceedings of the 1988 International Conference on Drilling Wastes, Calgary, Alberta, Canada, 461 to 479. Neff JM, (2005). Composition, Environmental Fates, and Biological Effect of Water Based Drilling Muds and Cuttings Discharged to the Marine Environment. Battelle. Neff, J., S. Johnsen, T. K. Frost, T. I. R. U. and Durell, G. S., 2006. Oil well produced water discharges to the North Sea. Part II: Comparison of deployed mussels (Mytilus edulis) and the DREAM model to predict ecological risk. Marine Environmental Research 62 (2006) 224–246. Nowacek DP, Thorne LH, Johnston DW and Tyack PL (2007). Responses of cetaceans to
November 2010
anthropogenic noise. Mammal Review, 37(2), 81 – 115. NRC (2005). Marine mammal populations and ocean noise, determining when noise causes biologically significant effects. Washington, DC.: The National Academy Press. NSTF (1993). North Sea Quality Status Report, Oslo and Paris Commissions, Olsen and Olsen, Denmark, 132 pp. OGP (2005). OGP 2005, Fate and Effects of Naturally Occurring Substances in Produced Water on the Marine Environment. OGP, (2010). E&P Sound and Marine Life Programme. Available online at http://www.soundandmarinelife.org/Site/index.html [Accessed 15/07/10]. Oil and Gas UK (2008). 2007 Offshore Emissions Associated with Exploration and Production Activities, as Reported to DECC. Oil and Gas UK (2009). Accident statistics for offshore units on the UKCS 1990-2007. Issue 1, April 2009. Co-sponsored by the Health and Safety Executive. Available online at http://www.oilandgasuk.co.uk/issues/health/docs/U KCS_accident_statistics_offshore_units.pdf. OSPAR Commission (2000). Quality Status report 2000, region II – Greater North Sea. OSPAR Commission, London, 136 pp. OSPAR Commission (2009). Assessment of impacts of offshore oil and gas activities in the North-East Atlantic. Offshore Industry Series Publication Number: 453/2009. ISBN 978-1906840-93-8. OSR (Oil Spill Response) (2010). Oil Spill Modelling undertaken on behalf of Xodus Group. Oil Spill Response Project Number 4138. Parks SE, Clark CW and Tyack PL (2007). Short and long-term changes in right whale calling behavior: the potential effects of noise on communication. Journal of the Acoustical Society of America, 122(6), 3725 – 3731. Pearson TH, Mannuk HP, Evans R and FalkPeterson S (1996). The benthic communities of the Snorve field in the northern North Sea. Peterson, C.H., Holland-Bartels, L., 2002. Chronic impacts of oil pollution in the sea: risk to vertebrate predators. Mar. Ecol. Progress Ser. 241, 235–236. PI Energy and Emissions Ltd (2008). Report to BP, Quad 204 Energy and Emissions Forecasts. BP Document Reference J032-7460-01-Rev. 2. . PIENKOWSKI, M. W. (1980). Differences in habitat
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requirements and distribution patterns of plovers and sandpipers at investigated by studies of feeding behaviour. (Proc. IWRB Feeding Ecology Symp., Gwatt, Switzerland, 1977.) Vehrn. Orn. Ges. Bayern 23: 105-124.
Robson CF (1997b). Chapter 5.7 Fish: Exploited sea fish. In: Barne JH, Robson CF, Kaznowska SS, Doody JP, Davidson NC and Buck Al (Eds). Coasts and seas of the United Kingdom. Region 1 Shetland. JNCC, Peterborough.
PIENKOWSKI, M. W. (1981). How foraging plovers cope with environmental effects on invertebrate behaviour and availability. Pp. 179-192 in: N. V Jones and W. J. Wolff (eds.), Feeding and Survival Strategies of Atuarine Organisms. New York and London. (Plenum Press).
RSPB (2009). Birds of conservation concern, (2009). Available online at http://www.rspb.org.uk/Images/BoCC_tcm9217852.pdf [Accessed 22/03/10].
Pollock CM, Mavor R, Weir CR, Reid A, White RW, Tasker ML, Webb A and Reid JB (2000). The distribution of seabirds and marine mammals in the Atlantic Frontier, north and west of Scotland, JNCC report. Reed, M. et al., 2001: DREAM: a Dose-Related Exposure Assessment Model. Technical Description of Physical-Chemical Fates Components. Proceedings 5th Int. Marine Environmental Modelling Seminar, New Orleans, USA, Oct. 9-11 2001. Reed, M., and Hetland, B., 2002. DREAM: a DoseRelated Exposure Assessment Model Technical Description of Physical-Chemical Fates Components. SPE 73856. Reid DG, Turrell WR, Walsh M and Corton A (1997). Cross-shelf processes North of Scotland in relation to the southerly migration of western mackerel. ICES Journal of marine science, 54, 168 – 178. Reid J, Evans PGH and Northridge S (2003). An atlas of cetacean distribution on the northwest European Continental Shelf. Joint Nature Conservation Committee, Peterbourgh. Reid JB, Pollock CM and Mavor R (2001). Seabirds of the Atlantic Frontier, north and west of Scotland. Continental Shelf Research, 21, 1029 – 1045. Richardson JW, Greene Jr CR, Malme CI and Thomson DH (1995). Marine Mammals and Noise. Academic Press, Inc. San Diego, California, 576 pp. Robinson GA (1970). Continuous plankton records: variation in the seasonal cycle of phytoplankton in the North Atlantic. Bulletin of Marine Ecology, 6, 333 – 345. Robson CF (1997a). Chapter 5.7 Fish: exploited sea fish. In: Barne JH, Robson CF, Kaznowska SS, Doody JP, Davidson NC and Buck Al (Eds). Coasts and seas of the United Kingdom. Region 2 Orkney. JNCC. Peterborough.
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Rye, H., Reed, M., Frost, T.K., Smit, M.G.D., Durgut, I., Johansen, Ø., Ditlevsen, M.K., 2008. Development of a numerical model for calculation of exposure to toxic and non-toxic stressors in water column and sediment from drilling discharges. The SETAC journal Integrated Environmental Assessment and Management 4:194-203. Rye H, Reed M, Durgut I and Ditlevsen MK (2006). The use of the diagentic equations to predict impact on sediment due to discharges of drill cuttings and mud. Paper presented at the 9th Int. Marine Environmental Modelling Seminar, Rio de Janeiro Brazil, October 9 -11, 2006. Rye, H., Reed, M., Durgut, I.and Ditlevsen, M.K., 2006. Documentation report for the revised DREAM model. SINTEF Report no. STF80MK ERMS. Rye, H., Reed, M. Ekrol, N., Johnsen, S. and Frost, T., 1998. Accumulated Concentration Fields in the North Sea for Different Toxic Compounds in Produced Water. SPE 46621. SAMS (2001). Deep water fish of the Northeastern Atlantic. Poster prepared by SAMS and sponsored by business source information, Highlands and Islands Enterprise, Ross and Cromarty District Council and Denholm Fishselling Ltd. Scandpower, (1999). Appendix A Data Dossier. Blowout Frequency data. Scandpower A/S. Schaaning, M., and Bakke, T., 2006. Remediation of sediments contaminated with drill cuttings. NIVA Report no. 5188-2006, ERMS Report no. 22. Scottish Government (1998). PAN 58 Environmental Impact Assessment. Available online at http://www.scotland.gov.uk/Publications/1999/10/p an58-root/pan58 [Accessed 24/09/10]. SeaWIFs (2002). SeaWIFs website at http://weawifs.gsfc.nasa.gov/seawifs.html [Accessed 01/02/10]. SERPENT, (2010). Deep sea research using ROVs. Available online at http://www.serpentproject.com/ [Accessed
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17/09/10]. SFF/Brown and May (2010). Commercial Fisheries Assessment for Offshore Oil and Gas Development in the West of Shetland. Report by SFF Services Ltd and Brown and May Marine, 2010. Report reference QD-BP-EV-REP-0007. SINTEF (2010). DREAM Model Users Manual (Partial First Draft). Norway. SINTEF (Undated). Calculation of PNEC for changed grain size based on data from MOD Akvaplan-niva report APN-411.3088.1 Singsaas, I., Rye, H., Frost, T.K., Smit, M.G.D., Garpestad, E., Skare, I., Bakke, K., Veiga, L.F., Buffagni, M, Follum, O.A., Johnsen, S., Moltu, U.E., Reed, M., 2008: Development of a risk-based environmental management tool for drilling discharges. Summary of a Four-Year project. The SETAC journal Integrated Environmental Assessment and Management 4:171-176. Smit, M.G.D, Jak, R.G., Rye, H., Frost, T.K., Singsaas, I. and Karman, C.C., 2008: Assessment of environmental risks from toxic and nontoxic stressors; a proposed concept for a risk-based management tool for offshore drilling discharges. The SETAC journal Integrated Environmental Assessment and Management 4:177-183. SMRU (2008). Information on cetaceans around the Schiehallion field 60°21'6.53" N and 04°10'51.82" W. SNH (2010). SiteLink Home V2. Available online at http://gateway.snh.gov.uk/ [Accessed 07/07/10]. SNH, (2006). Moray Firth SAC, Advice under regulation 33(2) of the conservation (Natural Habitats Act) Regulations 1994 (as amended). Southall BL, Bowles EA, Ellison WT, Finneran JJ, Gentry RL, Greene CR, Kastak D, Ketten D, Miller JH, Nachtigall PE, Richardson WJ, Thomas JA and Tyack PL (2007). Marine Mammal Noise Exposure Criteria: Initial Scientific Recommendations. Aquatic Mammals, 33(4), 411 - 521. Spence J, Fischer R, Bahtiarian M, Boroditsky L, Jones N and Dempsey R (2007). Review of Existing and Future Potential Treatments for Reducing Underwater Sound from Oil and Gas Industry Activities. Prepared by Noise Control Engineering Inc, MA, for Joint Industry Programme on E&P Sound and Marine Life, London. NCE Report 07-001. Stoker MS, Hitchen K and Graham CC (1993). United Kingdom Offshore Regional Report: The Geology of the Hebrides and West Shetland
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Shelves and Deep-Water Areas. HMSO for the British Geological Survey, London. Stone CJ (2003a). Marine mammal observations during seismic surveys in 2000. JNCC Report No. 322. Stone CJ (2003b). The effects of seismic activity on marine mammals in UK waters 1998-2000. JNCC Report 323. Swift RJ and Thompson PM (2000). Identifying potential sources of industrial noise in the Foinaven and Schiehallion region. Report by the Lighthouse Field Station, University of Aberdeen, to BP Amoco Exploration, UK. Talisman (2006). Beatrice Wind Farm Demonstrator Project. Environmental Statement. D/2875/2005. Taylor SJ and Reid JB (2000). The distribution of seabirds and cetaceans around the Faroe Islands. Joint Nature Conservation Committee, Peterborough. Tech Environmental (2006). Cape Wind Energy Project, Nantucket Sound. Appendix 3.13-B Final EIR Underwater Noise Analysis. Prepared by Tech Environmental Inc, Massachusetts, Energy Management Inc, New England. Report No.5.3.22. Thomsen F, Ludemann K, Kafemann R and Piper W (2006). Effects of offshore wind farm noise on marine mammals and fish. Biola, Hamburg, Germany on behalf of COWRIE Ltd. TNO (2006). TNO report 2006-DH-004/A The derivation of a PNECwater for weighting agents in drilling mud. Tyack PL (2008). Implications for marine mammals of large-scale changes in the marine acoustic environment. Journal of Mammalogy, 89(3), 549 – 558. UKDEAL (2010). Oil and Gas UK DEAL. Available online at https://www.ukdeal.co.uk/ [Accessed 07/07/10]. UKMMAS (2010). Charting Progress 2. United Kingdom Marine Monitoring and Assessment Strategy, DEFRA. Available online at http://chartingprogress.defra.gov.uk/ [Accessed 19/08/10]. UKOOA (1999). Drill Cuttings Initiative, Research and Development Programme. Activity 2.1. Faunal Colonisation of Drill Cuttings Pile Based on Literature Review. United Kingdom Offshore Operators Association, Aberdeen, UK. UKOOA (2005). UKOOA JIP 2004, Drill Cuttings
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Initiative Phase III: final report 20132900, 26 January 2005. UKOOA (2006). Report on the analysis of DTI UKCS oil spill data from the period 1975 - 2005. October 2006. A report prepared by TINA Consultants Ltd.
(2006). Short-term effects of the prestige oil spill on the peregrine falcon (Falco peregrinus). Marine Pollution Bulletin 52 (2006) 1176 – 1181.
Urick RJ (1983). Principles of Underwater Sound. California: Peninsula Publishing. US National Research Council (2003). Ocean noise and marine mammals. Washington, DC; National Academy Press. Walker, D. A., Webber, P. J., Everett, K. R. and Brown, J. (1978). Effects of Crude and Diesel Oil Spills on Plant Communities at Prudhoe Bay, Alaska, and the Derivation of Oil Spill Sensitivity Maps ARCTIC VOL. 31, NO. 3 (SEPT. 1978), P. 242-259. Walsh M, Reid, DG and Turrell, WR (1995). Understanding mackerel migration off Scotland: Tracking with echosounders and commercial data and including environmental correlates and behaviour. ICES Journal of Marine Science, 52, 925 – 939. Wernham CV, Toms MP, Marchant JH, Clark JA, Sitiwardena GM and Baillie SR (2002). The migration atlas: Movements of the birds of Britain and Ireland. British Trust for Ornithology. ISBN 978-0-7136-6514-7. White P (2010). Analysis of Clair field noise measurements. Prepared by Paul White, Institute of Sound and Vibration Research, University of Southampton, for BP, Dyce. Wright PJ and Bailey MC (1993). The biology of sand eels in the vicinity of seabird colonies at Shetland. Marine Laboratory Aberdeen Research Report No 15/93. SOAFD, Aberdeen. Wyatt R (2008). Review of Existing Data on Underwater Sounds Produced by the Oil and Gas Industry - Issue 1. Report by Seiche Measurements Ltd., Great Torrington, to Joint Industry Programme on Sound and Marine Life, Seiche Measurements Limited Ref – S186. Xodus Aurora (2008). Quad204 Environmental Concept Screening Study. Doc Ref A-30034-S00REPT-01-R00. Report produced by Xodus Aurora, Aberdeen, on behalf of BP Exploration and Production Ltd, Aberdeen. Xodus Aurora (2010). Quad204 EIA Atmospherics Emission Modelling. Undertaken on behalf of BP Exploration Operating Company Ltd. Zuberogoitia, I,. Martinez, J.A., Iraeta, A., Azkona, A., Zabala, J., Jimenez, B., Merino, R & Gomez.
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Summary of Environmental Legislation
Appendix A Summary of Environmental Legislation Activity
Regulatory body
Legislation
Standards and requirements
Petroleum (Production) (Seaward Areas) (Amendment) Regulations 1995
Licence required for exploration and production in areas of the UKCS. This includes licences for tranches of blocks as well as individual blocks. Licence may include conditions for operations including environmental conditions.
Project approval and environmental assessment Licence areas
DECC
Petroleum Licensing (Exploration and Production) (Seaward and Landward Areas) Regulations 2004 Petroleum Licensing (Production) (Seaward Areas) Regulations 2008 Environmental Impact Assessment
DECC
Offshore Petroleum Production and Pipelines (Assessment of Environmental Effects) Regulations 1999
An Environmental Statement must be submitted for approval to DECC, having made an assessment of the impact that the project would have on the environment. Secretary of State may give a direction that an ES is not required for some projects.
Offshore Petroleum Production and Pipelines (Assessment of Environmental Effects) (Amendment) Regulations 2007 Energy Act 2008 (Consequential Modifications) (Offshore Environmental Protection) Order 2010 Pipeline Works Authorisation
DECC
Petroleum Act 1998 as amended
Authority is required from DECC for construction of a pipeline. Requires demonstration that environmental assessment has been made and consultation undertaken.
Consent to locate
DECC
Coast Protection Act 1949
Requires consent for the siting of offshore installations within UK territorial waters. Includes requirements for removal at end of life and consideration of obstruction to navigation. By the time the existing FPSO is replaced, the consent to locate will be subject to a new regime under the Energy Act 2008.
Continental Shelf Act 1964
Transboundary impacts
DECC
Convention on Environmental Assessment in a Transboundary Context 1991 Offshore Petroleum Production and Pipelines (Assessment of Environmental Effects) Regulations 1999 as amended
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Consideration of transboundary impacts is now widely expected in particular for Environmental Impact Assessment, Oil Pollution Emergency Planning and Chemicals Risk Assessment. Where a project may have a “significant transboundary environmental impact”, this must be considered.
Page A.1
Summary of Environmental Legislation Activity
Regulatory body
Legislation
Standards and requirements
Conservation areas and species
DECC/JNCC/ SNH
Council Directive on the Conservation of Natural Habitats and of Wild Fauna and Flora 92/43/EEC
Various conservation designations exist in the UK including Sites of Special Scientific Interest (SSSIs), Special Areas of Conservation (SACs), Special Protection Areas (SPAs) and World Heritage Sites. These designations afford different levels of protection over habitats or species present and due consideration must be given during the planning process. Where a project may be “likely to have a significant environmental effect” on a SAC, SPA, cSAC or pSPA an appropriate assessment must be undertaken. This applies to all UK waters.
Council Directive on the Conservation of Wild Birds 2009/147/EC Offshore Petroleum Activities (Conservation of Habitats) Regulations 2001 as amended by: Offshore Petroleum Activities (Conservation of Habitats) (Amendment) Regulations 2007 Conservation (Natural Habitats &c.) Amendment (Scotland) Regulations 2007 Offshore Marine Conservation (Natural Habitats &c.) Regulations 2010 Energy Act 2008 (Consequential Modifications) (Offshore Environmental Protection) Order 2010
Decommissioning
DECC
Petroleum Act 1998 as amended Energy Act 2008 as amended Offshore Marine Conservation (Natural Habitats &c) Regulations 2010 Offshore Petroleum Activities (Conservation of Habitats) Regulations 2001 as amended by: Offshore Petroleum Activities (Conservation of Habitats) (Amendment) Regulations 2007
Page A.2
Competent authorities are also required to ensure that steps are taken to avoid the disturbance of species and deterioration of habitat in respect of offshore marine sites and that any significant effects are considered before authorisation of certain plans or projects. It is also an offence under the Offshore Marine Conservation Regulations 2010 to deliberately disturb wild animals of a European Protected Species in such a way as to significantly affect a) the ability of any significant group of animals to survive or breed or b) the local distribution or abundance of that species. Where there is a risk to European Protected Species that cannot be removed or sufficiently reduced by the taking of mitigation measures, then a Wildlife Licence may be required. For new developments, decommissioning must be fully considered in the Field Development Plan and in the EIA. Under the Petroleum Act 1998, owners of an offshore installation or pipeline must obtain approval of a decommissioning programme before proceeding. If a decommissioning programme has not been submitted to DECC for approval, a notice under Section 29 of the Petroleum Act 1998 may be served by the Secretary of State requiring the recipient to submit a costed decommissioning programme for his approval at such future time as he may direct. The programme (referred to in the 1998 Act as an “abandonment programme”) should contain the measures proposed to be taken in connection with the decommissioning of an installation or pipeline. The decommissioning programme requirements implement the UK Government commitments under the OSPAR Convention as well as other international standards. The decommissioning programme must include (amongst others) removal and disposal options including identification of the preferred option; details regarding dealing with any cuttings pile; an environmental impact assessment; and pre and post-decommissioning monitoring and maintenance.
November 2010
Summary of Environmental Legislation Activity
Regulatory body
Legislation
Standards and requirements
Agreement on the Conservation of Small Cetaceans of the Baltic and North Seas (ASCOBANS)
Consent is required before undertaking seismic survey in all UK waters. The consent application must include assessment of any noise impacts on cetaceans in the area. Mitigation measures likely to be included include a marine mammal observer on board.
Seismic survey Noise
DECC/JNCC
Council Directive on the Conservation of Natural Habitats and of Wild Fauna and Flora 92/43/EEC Offshore Petroleum Activities (Conservation of Habitats) Regulations 2001 as amended by: Offshore Petroleum Activities (Conservation of Habitats) (Amendment) Regulations 2007 Energy Act 2008 (Consequential Modifications) (Offshore Environmental Protection) Order 2010
New regulations (Offshore Marine Conservation (Natural Habitats &c.) Regulations 2010) make it an offence to deliberately disturb wild animals of a European Protected Species in such a way as to significantly affect a) the ability of any significant group of animals to survive or breed or b) the local distribution or abundance of that species. Where there is a risk to European Protected Species that cannot be removed or sufficiently reduced by the taking of mitigation measures, then a Wildlife Licence may be required.
Offshore Marine Conservation (Natural Habitats &c.) Regulations 2010 Drilling and well operations Chemicals
DECC/Marine Scotland
OSPAR Decision 2000/2 on a Harmonised Mandatory Control System for the Use and Reduction of the Discharge of Offshore Chemicals Offshore Chemicals Regulations 2002 as amended (OCR)
WBM contaminated cuttings
November 2010
DECC/Marine Scotland
Offshore Chemicals Regulations 2002 as amended Offshore Petroleum Activities (Oil Pollution Prevention and Control) Regulations 2005 (OPPC)
Permit required to use and discharge chemicals. Application needs to list chemicals intended for use and indicate the amounts to be used together with the amounts expected to be discharged. The application will also need to include a risk assessment for the environmental effect of the discharges of chemicals into the sea. Permits include conditions such as monitoring, reporting and substitution/mitigation for more hazardous chemicals. Muds and chemicals used and discharged must be reported (see Chemicals). An OPPC permit is required to discharge cuttings and/or water based muds contaminated by reservoir hydrocarbons when drilling through the pay zone. End of well reporting of chemical use required to DECC and summary to EEMS.
Page A.3
Summary of Environmental Legislation Activity
Regulatory body
OBM (OPF) contaminated cuttings
DECC/Marine Scotland
Legislation
Standards and requirements
Offshore Chemicals Regulations 2002 as amended
Use of diesel oil based drilling fluids is prohibited. The discharge of whole OPF is prohibited. The discharge of cuttings contaminated with oil-based fluids (OBF) greater than 1% by weight on dry cuttings is prohibited, which with current technology effectively prohibits discharge of OPF/OBM contaminated cuttings to sea. Encouragement is given to recycling, recovery and reuse of muds. The following options for disposal should be considered in order to reduce discharges: transportation to shore, re-injection of cuttings and offshore treatment. Muds and chemicals used must be reported (see Chemicals). End of well returns are required to be made for all relevant permits (PON15) issued by DECC. For well operations completed EEMS forms must be submitted one month after completion of drilling.
OSPAR Decision 2000/3 on the Use of OrganicPhase Drilling Fluids (OPF) and the Discharge of OPF Contaminated Cuttings Offshore Petroleum Activities (Oil Pollution Prevention and Control) Regulations 2005
Drill cuttings contaminated with Reservoir Hydrocarbons will require an OPPC permit if being discharged. Cuttings re-injection
DECC/Marine Scotland
Food and Environment Protection Act 1985 Deposits in the Sea (Exemptions) Order 1985 Offshore Chemicals Regulations 2002 as amended Offshore Petroleum Activities (Oil Pollution Prevention and Control) Regulations 2005
Well testing
DECC
Offshore Chemicals Regulations 2002 as amended Offshore Petroleum Activities (Oil Pollution Prevention and Control) Regulations 2005
Re-injection of drill cuttings and associated chemicals downhole at the site of production is exempt from the requirements of a FEPA licence. However, export of drill cuttings and associated waste streams for re-injection at a remote site requires a licence. A chemical permit is required for any pre-treatment of cuttings prior to re-injection (if applicable). A permit under the OPPC Regulations will also be required if there is any contamination of cuttings by reservoir hydrocarbons. Any chemical use proposed for well testing operations will require a permit under the OCR. Well test water discharges may contain hydrocarbon and this requires an OPPC term permit.
Operations Produced water
DECC
Convention on the Protection of the Marine Environment of the North East Atlantic 1992 OSPAR Recommendation 2001/1 for the Management of Produced Water on Offshore Installations as amended by: OSPAR Recommendation 2006/4 Offshore Petroleum Activities (Oil Pollution Prevention and Control) Regulations 2005
Base case for any new development is zero discharge of produced water. Moving away from this requires demonstration/justification to DECC. DECC put particular emphasis on new facilities achieving PWRI and place less emphasis on subsea tie-back to existing facilities where there is no PWRI in place already. However, justification and demonstration of BAT/BPEO is still required. DECC PWRI availability target of 95% by volume. OPPC permit is required for discharge. Monthly average dispersed oil in water content of 30 mg/l. Maximum dispersed oil in water content of 100 mg/l. Dilution e.g. with seawater to achieve this oil in water concentration is not allowed. Monthly reporting of produced water reinjected and discharged to DECC and EEMS.
Page A.4
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Summary of Environmental Legislation Activity
Regulatory body
Produced sand
DECC
Legislation
Standards and requirements
Offshore Petroleum Activities (Oil Pollution Prevention and Control) Regulations 2005
OPPC permit is required for discharge. The performance standards relating to the discharge of produced sand are specific to each case. Maximum concentration of oil and permitted location of discharges will be detailed in the permit schedule, and will normally require that BAT is being used to limit the discharge of oil. End of year reporting of total quantity of sand and monthly oil content to DECC.
Low specific activity (LSA) contaminated waste (sand, scale and sludge)
SEPA/DECC
Radioactive Substances Act 1993 Radioactive Substances (Substances of Low Activity) Exemption Order 1986 Offshore Petroleum Activities (Oil Pollution Prevention and Control) Regulations 2005
Chemicals
DECC/Marine Scotland
OSPAR Decision 2000/2 on a Harmonised Mandatory Control System for the Use and Reduction of the Discharge of Offshore Chemicals Offshore Chemicals Regulations 2002 as amended
November 2010
Certification of authorisation to accumulate and dispose of low-level radioactive liquid waste required. Excludes liquid waste where radioactivity does not exceed 0.4 Bq/ml. OPPC permit required for disposal of sand/scale/sludge also contaminated with hydrocarbons. Annual reporting to SEPA and reporting to DECC if oil is present. Permit required to use and discharge chemicals. Application needs to list chemicals intended for use and indicate the amounts to be used together with the amounts expected to be discharged. The application will also need to include a risk assessment for the environmental effect of the discharges of chemicals into the sea. Permits include conditions such as monitoring, reporting and substitution/mitigation for more hazardous chemicals.
Page A.5
Summary of Environmental Legislation Activity
Regulatory body
Turbine and generator emissions
DECC
Legislation
Standards and requirements
Pollution Prevention and Control Act 1999 (PPC)
A PPC permit is required for any installation with combustion plant (gas turbines, diesel engines, direct drive compressors, heaters etc.) which on its own or together with any other combustion plant installed has a rated thermal input exceeding 50 MW(th).
Offshore Combustion Installations (Prevention and Control of Pollution) Regulations 2001 as amended by: Offshore Combustion Installations (Prevention and Control of Pollution) (Amendment) Regulations 2007 Energy Act 2008 (Consequential Modifications) (Offshore Environmental Protection) Order 2010 EU Emissions Trading Scheme (EU Directive 2003/87/EC) UK Emissions Trading Scheme - Greenhouse Gas Emissions Trading Scheme Regulations 2005 (EU ETS) as amended by: Greenhouse Gas Emissions Trading Scheme (Amendment) Regulations 2007 Greenhouse Gas Emissions Trading Scheme (Amendment No.2) Regulations 2007
Demonstration of the following is required as part of the permit conditions: Appropriate pollution prevention measures through the application of Best Available Techniques (BAT) Production of non-gaseous waste is avoided where possible by using clean technologies or using waste minimisation/waste recovery technologies Energy is used efficiently (including need for energy efficiency audits) PPC also requires sampling/analysis of emissions therefore sample points are required at safe locations on the turbine stacks. Operators are required to report actual emissions on a yearly basis to DECC and demonstrate that the overall final emissions target(s) remain achievable. BP is registered under the EU Emissions Trading Scheme (EU ETS). Any installation with combustion plant that on its own or in aggregate with any other combustion plant has a rated thermal input exceeding 20 MW (th) is required to be registered under the EU ETS. Currently only CO2 emissions are covered by the EU ETS. It has been a requirement since 1st January 2008 that the sulphur content of Gas Oil must not exceed 0.1%.
Page A.6
November 2010
Summary of Environmental Legislation Activity
Regulatory body
Flaring, venting and reinjection of gas
DECC
Legislation
Standards and requirements
Energy Act 1976 Petroleum Licensing (Exploration and Production) (Seaward and Landward Areas) Regulations 2004
Consent required for flaring, venting or reinjection of gas unless permitted under specific terms of the production licence. Gas disposal volumes are restricted by consent. No statutory limits are set and the consent system is used to implement the UK Government policy and international obligations on atmospheric emissions (e.g. United Nations Framework Convention on Climate Change 1992 and Kyoto Protocol 1997).
Petroleum (Production) (Seaward Areas) Regulations 2008
Operators are required to report flare volumes to DECC at periods specified in consent and report flaring and venting emissions to EEMS.
Pollution Prevention and Control Act 1999
BP is registered under the EU Emissions Trading Scheme (EU ETS). The Scheme enables greenhouse gas emission allowance trading. Flaring was included in this Scheme from 2008 onwards.
Petroleum Act 1998 as amended
UK Emissions Trading Scheme - Greenhouse Gas Emissions Trading Scheme Regulations 2005 as amended by: Greenhouse Gas Emissions Trading Scheme (Amendment) Regulations 2007, and
Vent levels (steady state) > 5 tonnes per day are considered by DECC to represent opportunity for reduction and will require justification for new field development including demonstration of BAT/Best Practice.
Greenhouse Gas Emissions Trading Scheme (Amendments No. 2) Regulations 2007 Energy Act 2008 (Consequential Modifications) (Offshore Environmental Protection) Order 2010 Drainage (open drains systems from hazardous and non-hazardous areas)
DECC
Offshore Petroleum Activities (Oil Pollution Prevention and Control) Regulations 2005 (OPPC)
Permit required for all oily drainage (excluding machinery space drainage) under OPPC Regulations. The monthly average concentration of dispersed oil in drainage water must not exceed 40 mg/l. The maximum concentration of dispersed oil must not exceed 100 mg/l at any time. Arrangements must be in place to ensure oil recovery from the open drains systems before discharge. Any oil recovery system must be operated to maximise recovery of oil.
Machinery space drainage
DECC on behalf of MCA
MARPOL 73/78 (Annex I) (entered info force Oct. 1983) Merchant Shipping Act 1995 Merchant Shipping (Prevention of Oil Pollution) Regulations 1996 as amended by: Merchant Shipping (Prevention of Oil Pollution) (Amendment) Regulation 2005 Merchant Shipping (Implementation of Ship-Source Pollution Directive) Regulations 2009
November 2010
UKOPP or IOPP certification is required for all vessels and installations. Northwest European Waters are now a Special Sea Area under Annex I of MARPOL 73/78. Discharge of oily water from shipping is therefore prohibited with the exception of machinery space drainage, which is subject to a number of conditions including maximum oil in water content of 15mg/l. Installation or vessel must also have in place means of oil-in-water separation and discharge monitoring systems. These regulations only apply to machinery space drainage (bilges) and not drainage associated with production/process systems. Where all drainage is fed via the production/process drainage systems for treatment, these Merchant Shipping Regulations will not apply.
Page A.7
Summary of Environmental Legislation Activity
Regulatory body
Grey water and cooling water
-
Legislation
Standards and requirements
Food and Environment Protection Act 1985
Discharges exempt from licensing. No reporting required.
Deposits in Sea Exemption Order 1985 Sewage
MCA
MARPOL 73/78 (Annex IV) (entered into force Sept 2003) Merchant Shipping (Prevention of Pollution by Sewage and Garbage from Ships) Regulations 2008
MARPOL details how sewage should be treated or held onboard and the circumstances in which discharge into the sea may be allowed. Requires adequate reception facilities for sewage to be provided. Sewage equipment is required only by vessels of >400 GRT or <400 GRT if certified to carry more than 15 persons if engaged in international voyages. The requirements for sewage equipment will therefore apply to mobile drilling units or other vessels (e.g. FPSO) on international voyage.
Garbage and galley waste
MCA/SEPA
MARPOL 73/78 (Annex V) (entered into force December 1988) Merchant Shipping and Fishing Vessels (Port Waste Reception Facilities) Regulations 2003 as amended Merchant Shipping (Prevention of Pollution by Sewage and Garbage) Regulations 2008
With North West European waters being a Special Sea Area under Annex V of MARPOL 73/78, disposal of garbage (including plastics) and galley waste (except ground food wastes) overboard is prohibited Adequate storage facilities must be provided for on the installation to enable appropriate back-shipment to shore to meet UK waste management legislation (see Waste handling and disposal). A Garbage Management Plan and garbage record book must be kept which will be subject to inspection.
Vessel atmospheric emissions (marine diesel engines)
MCA
MARPOL 73/78 (Annex VI) (entered into force May 2005) Council Directive 2005/33/EC amending Directive 1999/32/EC with regards the sulphur content of marine fuels Sulphur Content of Liquid Fuels (Scotland) Regulations 2000 Merchant Shipping (Prevention of Air Pollution from Ships) Regulations 2008 as amended by: Merchant Shipping (Prevention of Air Pollution from Ships) (Amendment) Regulations 2010.
Applies to Nitrogen oxide (NOx) and Sulphur oxide (SOx ) emissions from marine engines, including those on offshore installations. Annex VI sets limits on NOx and SOx . The implementing Regulations for Scotland (2000) set out the maximum sulphur content for fuel including heavy fuel oil and gas oil including marine fuel. Although these regulations will eventually be replaced for marine fuel (UK wide regulations to be put in place) there is a requirement that from the 1st of January 2008 the sulphur content of gas oil must not exceed 0.1%. Although the provisions of Annex VI are not yet fully implemented in the UK, the MCA has put into place interim provisions for vessels (including offshore installations) constructed after 1st January 2000. However, diesel engines on offshore installations, platforms and drilling rigs which are solely dedicated to the exploration, exploitation and associated offshore processing are excluded from these requirements. Use of low sulphur diesel is required.
Page A.8
November 2010
Summary of Environmental Legislation Activity
Regulatory body
Halocarbons and refrigerants
DECC
Legislation
Standards and requirements
Vienna Convention 1985 and Protocols
Placing on the market/use of CFCs and halons in equipment was prohibited from 1 October 2000. The use of CFCs and halons for maintenance of equipment was banned from 1 January 2001. There is currently an exception for the critical use of halons in fire protection equipment.
Environmental Protection (Control on Substances that Deplete the Ozone Layer) Regulations 1998 EC Regulation No. 842/2006 on Certain Fluorinated Greenhouse Gases Fluorinated Greenhouse Gases Regulations 2008
Use of HCFCs in newly manufactured equipment is prohibited. Although there are some short-term exceptions, companies should endeavour to select new equipment that does not utilise HCFC gases or blends of them.
Environmental Protection (Controls on OzoneDepleting Substances) Regulations 2002 as amended by: Environmental Protection (Controls on OzoneDepleting Substances) (Amendment) Regulations 2008 EC Regulation No. 1005/2009 on substances that deplete the ozone layer Noise
DECC/JNCC
Agreement on the Conservation of Small Cetaceans of the Baltic and North Seas (ASCOBANS) Council Directive on the Conservation of Natural Habitats and of Wild Fauna and Flora 92/43/EEC Council Directive on the Conservation of Wild Birds 79/409/EEC Offshore Petroleum Activities (Conservation of Habitats) Regulations 2001 as amended by: Offshore Petroleum Activities (Conservation of Habitats) (Amendment) Regulations 2007
Acoustic disturbance from operational and construction noise and potential impacts on cetaceans needs to be considered during planning; this is likely to be undertaken through the Environmental Impact Assessment. No statutory reporting requirements currently in place for operational/drilling noise. The Offshore Marine Conservation Regulations (2007) make it an offence to intentionally disturb animals which are protected by a designated or listed site. This includes the intentional disturbance of wild birds in a classified site and the intentional or reckless damage or destruction of habitats. Where there is a risk to European Protected Species that cannot be removed or sufficiently reduced by the taking of mitigation measures, then a Wildlife Licence may be required.
Offshore Marine Conservation (Natural Habitats &c.) Regulations 2007 as amended by: Offshore Marine Conservation (Natural Habitats &c.) (Amendment) Regulations 2010 Energy Act 2008 (Consequential Modifications) (Offshore Environmental Protection) Order 2010
November 2010
Page A.9
Summary of Environmental Legislation Activity
Regulatory body
Vessel anti-fouling
MCA
Legislation
Standards and requirements
Merchant Shipping (Anti-Fouling Systems) Regulations 2009
Fixed or Floating Platforms, FSUs and FPSOs constructed on or after 01 July 2003 must either not bear organotin compounds at all, or if they do, then they must have a barrier coating to prevent the compounds leaching. Fixed or Floating Platforms, FSUs and FPSOs constructed before 1 July 2003 and which have been in dry dock on or after 01 July 2003: similarly, these must either not bear organotin compounds at all, or if they do, then they must have a barrier coating to prevent the compounds leaching.
Pipelines Hydrotest water
DECC
Petroleum Act 1998 as amended Offshore Petroleum Activities (Oil Pollution Prevention and Control) Regulations 2005 Offshore Chemicals Regulations 2002 as amended
Pipelines that have a Pipeline Works Authorisation (PWA) are exempt from requiring a licence under FEPA. [FEPA Reg 7A Exempts construction or maintenance of a pipeline as respects any part of which an authorisation (within the meaning of Part III of the Petroleum Act 1998) is in force] However, under the terms of the PWA, the prior written consent of the Secretary of State is necessary before a discharge can take place. An OPPC permit is also required if an oily discharge is expected. A chemical permit is also required (see Chemicals).
Pipeline stabilisation
DECC
Petroleum Act 1998 as amended
The Pipelines Works Authorisation, issued prior to construction, governs the permanent placing or deposition of materials such as gravel, rock, mattresses or protective covers on the seabed during the construction of a pipeline.
Environmental Protection Act (EPA) 1990
Controlled waste is defined as “household waste, industrial waste, commercial waste or any such waste”. Controlled wastes may also be further defined as Special Wastes and additional requirements will apply. No direct offshore control. However, all waste must have accurate descriptions and appropriate segregation measures in place in order to ensure legal onshore disposal at appropriately licensed sites through properly licensed waste disposal contractors. EPA imposes a “duty of care” on the waste producer and waste handler.
Waste disposal and transport of dangerous goods Waste handling and disposal
SEPA
Controlled Waste Regulations 1992 as amended Environmental Protection (Duty of Care) Regulations 1991 Landfill (Scotland) Regulations 2003 Special Waste Regulations 1996 amended by: Special Waste Amendment (Scotland) Regulations 2004 Merchant Shipping (Prevention of Pollution by Sewage and Garbage from Ships) Regulations 2008
Page A.10
Transfer of controlled waste requires a ‘transfer note’ to be completed. This requirement includes waste landed from offshore that is then being onward transported. The transfer note must contain a detailed description of the waste and the correct Waste Catalogue Number. The transfer note must accompany the waste.
November 2010
Summary of Environmental Legislation Activity
Regulatory body
Special waste
SEPA
Legislation
Standards and requirements
Environmental Protection Act (EPA) 1990
Special waste is controlled waste, which is dangerous and difficult to handle. Radioactive waste may also be classified as special waste. Special wastes include oily wastes (e.g. waste hydraulic oils, waste engine gear and lubricating oils, waste heat transmission oils), waste from oil/water separators, waste from coolants, batteries, incineration and combustion plant wastes etc. Special waste taken to shore for disposal should be passed to a registered waste carrier and disposed of to an appropriately licensed waste disposal site. No mixing of non-hazardous (controlled) waste and special wastes is allowed.
Controlled Waste Regulations 1992 Environmental Protection (Duty of Care) Regulations 1991 Landfill (Scotland) Regulations 2003 Special Waste Regulations 1996 amended by:
Radioactive waste
SEPA
Special Waste Amendment (Scotland) Regulations 2004
Transfer of special/hazardous waste onshore requires a ‘waste consignment note’ to be completed. This requirement includes waste landed from offshore that is then being transported onwards.
OSPAR Convention
The London Dumping Convention defines radioactive waste as either “high-level” or “low-level”. Disposal at sea of high-level waste is prohibited. Disposal of low-level waste may be allowed under certain conditions (see LSA scale). The Radioactive Substances Act 1993 requires prior authorisation to accumulate or dispose of radioactive waste. Radioactive waste may also be defined as special waste and additional disposal requirements will apply.
London Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matters 1972 Radioactive Substances Act 1993 Merchant Shipping (Dangerous Goods and Marine Pollutants) Regulations 1997 Transfrontier Shipment of Radioactive Waste and Spent Fuel Regulations 2008 Transport of dangerous goods
MCA
MARPOL 73/78 (Annex II and III) Merchant Shipping (Dangerous or Noxious Liquid Substances in Bulk) Regulations 1996 Merchant Shipping (Dangerous Goods and Marine Pollutants) Regulations 1997
November 2010
Ships carrying packaged dangerous goods or marine pollutants must have a dangerous goods or marine pollutant declaration for each consignment containing the relevant technical information describing the goods/pollutants. Goods must also be appropriately packaged and stored securely onboard the vessel.
Page A.11
Summary of Environmental Legislation Activity
Regulatory body
Legislation
Standards and requirements
Pollution Prevention and Control Act 1999
All oil spills observed must be reported immediately. Oil Pollution Emergency Plan (OPEP) required for all fixed and floating installations, including mobile drilling units and pipelines. OPEP required to be submitted to DECC for approval at least 2 months before commencement of operation. Any major change in operations requires resubmission of the OPEP. OPEP must be resubmitted for approval on a 5-year cycle. MCA is the competent authority in the UK for oil pollution response and they have powers of intervention with respect to vessels and offshore installations to prevent and reduce pollution or the risk of pollution by oil or chemicals.
Accidental events Oil and chemical spills (installations and mobile drilling units)
DECC/MCA
Merchant Shipping Act 1995 Merchant Shipping (Oil Pollution Preparedness, Response and Co-operation Convention) Regulations 1998 as amended Offshore Installations (Emergency Pollution Control) Regulations 2002
Oil and chemical spills (vessels)
MCA
MARPOL 73/78 (Annex II and III) Merchant Shipping (Oil Pollution Preparedness, Response and Co-operation Convention) Regulations 1998
Approval of Shipboard Oil Pollution Emergency Plan (SOPEP). Vessels must also have in place an International Oil Pollution Prevention (IOPP) Certificate or UK Oil Pollution Prevention (UKOPP) Certificate. Vessels carrying dangerous goods or chemicals must have additional requirements in place (see Transport of dangerous goods).
Merchant Shipping (Reporting Requirements for Ships Carrying Dangerous or Polluting Goods) Regulations 1994
Chemical discharges
DECC/ Marine Scotland
Offshore Chemicals Regulations 2002 as amended Offshore Installations (Emergency Pollution Control) Regulations 2002
Discharges (including accidental) of chemicals exceeding agreed usage under OCR permit must be reported. MCA is the competent authority in the UK for pollution response and they have powers of intervention with respect to vessels and offshore installations to prevent and reduce pollution or the risk of pollution by oil or chemicals.
Merchant Shipping (Reporting Requirements for Ships Carrying Dangerous or Polluting Goods) Regulations 1994
Page A.12
November 2010
Summary of Environmental Legislation Activity
Regulatory body
Legislation
Standards and requirements
OSPAR Decision 98/3 on the Disposal of Disused Offshore Installations
For new developments, decommissioning must be fully considered in the Field Development Plan and in the EIA.
Petroleum Act 1998 as amended
Under the Petroleum Act 1998, owners of an offshore installation or pipeline must obtain approval of a decommissioning programme before proceeding.
Decommissioning Installations
DECC
Energy Act 2008 as amended
The decommissioning programme requirements implement the UK Government commitments under the OSPAR Convention as well as other international standards. The decommissioning programme must include (amongst others) removal and disposal options including identification of the preferred option’ details regarding dealing with any cuttings pile’ an environmental impact assessment, and pre and post-decommissioning monitoring and maintenance. Well abandonment and suspension
DECC/JNCC
Petroleum Act 1998 as amended Energy Act 2008 as amended Offshore Petroleum Activities (Oil Pollution Prevention and Control) Regulations 2005 Offshore Chemicals Regulations 2002 as amended Offshore Petroleum Activities (Conservation of Habitats) Regulations 2001 as amended by: Offshore Petroleum Activities (Conservation of Habitats) (Amendment) Regulations 2007
Permits are required for chemicals used during well abandonment; oil discharges relating to deliberate release of oil (reservoir hydrocarbons only) planned during a well suspension or abandonment; and a special licence for deposits to seabed in exceptional cases e.g. rock dumping to cover a wellhead. If there are intentions to use explosives in abandonment operations, discussions must be held with DECC and JNCC to ensure that consideration is given to any habitats or species. There is a need to ensure that offshore oil and gas installations and oil and gas wells are designed, constructed and kept in a sound structural state, and other requirements affecting them, for purposes of health and safety.
Energy Act 2008 (Consequential Modifications) (Offshore Environmental Protection) Order 2010 Offshore Installation and Wells (Design and Construction etc) Regulations 1996 Chemicals
DECC
Offshore Chemicals Regulations 2002 as amended Petroleum Act 1998 as amended Energy Act 2008 as amended
November 2010
The Offshore Chemicals Regulations apply to any use and discharge of chemicals from offshore oil and gas operations, including decommissioning operations. An application needs to be made to DECC for approval of a decommissioning programme. This programme will include consideration of chemicals to be used and discharged during decommissioning. However, full application will still be needed under the Offshore Chemicals Regulations 2002.
Page A.13
Summary of Environmental Legislation
This page has been deliberately left blank
Page A.14
November 2010
Environmental Performance Requirements
Appendix B Environmental Performance Requirements
November 2010
Page B.1
Environmental Performance Requirements
Page B.2
November 2010
Forecast Production Data
Appendix C Schiehallion and Loyal Forecast Production Data Introduction The following sections in this Appendix provide details on: h Peak production forecasts for oil, gas and produced water for Schiehallion and Loyal from 2010 – 2035 to accompany the figures provided in Chapter 3. These data represent the highest predicted production rates and form the basis of the emissions and discharges estimates used in the EIA. h Average production forecasts for oil, gas and produced water for Schiehallion and Loyal from 2010 – 2035 and associated figures. These data are consistent with the data provided in the Schiehallion and Loyal Field Development Plans.
Peak production forecast data Note: There will be no production between 2Q 2014 and 3Q 2015. Existing FPSO production will cease in 1Q 2014 with new FPSO production expected from 4Q 2015. Year
Schiehallion existing wells 3
Loyal existing wells
3
mbd
m /day
t/day
mbd
m /day
t/day
2010
33.4
5,315
4,773
4.5
714
2011
34.3
5,453
4,897
4.6
2012
46.9
7,463
6,702
2013
34.8
5,536
2014
5.3
2015
Q204 Schiehallion 20 infill wells (base case) 3
m /day
t/day
mbd
3
m /day
t/day
Total peak oil production rate 3
mbd
m /day
t/day
645
37.9
6,029
5,418
733
662
38.9
6,186
5,560
5.9
945
854
52.9
8,408
7,556
4,971
4.0
640
579
38.8
6,176
5,550
846
759
0.6
98
88
5.9
944
848
10.6
1,687
1,515
0.8
132
119
1.1
173
155
0.5
85
77
13.1
2,076
1,866
2016
113.7
18,081
16,237
11.4
1,814
1,640
5.1
815
732
8.4
1,340
1,211
138.7
22,049
19,819
2017
91.9
14,605
13,116
9.6
1,522
1,376
6.5
1,026
921
8.6
1,369
1,237
116.5
18,522
16,650
2018
71.4
11,355
10,197
7.9
1,253
1,133
15.6
2,484
2,231
9.9
1,577
1,426
104.9
16,670
14,987
2019
61.3
9,746
8,752
6.7
1,066
964
21.9
3,483
3,127
10.3
1,639
1,481
100.2
15,934
14,325
2020
54.8
8,708
7,820
6.0
958
866
17.3
2,746
2,466
9.1
1,447
1,308
87.2
13,859
12,460
2021
48.7
7,744
6,954
5.5
869
786
13.2
2,106
1,891
6.5
1,041
941
74.0
11,759
10,571
2022
44.7
7,105
6,380
5.0
798
721
9.6
1,520
1,365
5.2
824
745
64.4
10,247
9,211
2023
39.1
6,218
5,583
4.7
742
671
9.3
1,486
1,334
4.1
658
595
57.3
9,104
8,183
2024
35.9
5,709
5,127
4.4
703
636
6.9
1,097
985
3.2
505
456
50.4
8,014
7,203
2025
33.4
5,314
4,772
4.2
675
610
4.9
783
703
2.5
391
354
45.1
7,164
6,439
2026
30.6
4,858
4,362
3.9
627
567
4.8
757
680
2.2
351
317
41.5
6,593
5,926
2027
29.2
4,635
4,162
3.5
552
499
4.9
783
703
2.1
333
301
39.6
6,303
5,665
2028
26.6
4,231
3,800
3.3
525
475
4.6
731
657
1.9
308
279
36.5
5,796
5,210
2029
24.7
3,928
3,528
3.0
469
424
4.9
786
706
2.4
374
339
35.0
5,557
4,996
November 2010
mbd
Q204 Loyal 5 infill wells (base case)
Page C.1
Forecast Production Data Year
Schiehallion existing wells 3
Loyal existing wells
3
Q204 Schiehallion 20 infill wells (base case) 3
Q204 Loyal 5 infill wells (base case) 3
Total peak oil production rate 3
mbd
m /day
t/day
mbd
m /day
t/day
mbd
m /day
t/day
mbd
m /day
t/day
mbd
m /day
t/day
2030
23.4
3,728
3,348
2.8
449
406
4.9
777
698
2.2
356
322
33.4
5,310
4,773
2031
24.4
3,874
3,479
2.7
430
389
3.9
625
561
2.0
313
283
33.0
5,242
4,711
2032
28.2
4,477
4,020
2.7
425
385
3.3
525
471
1.5
246
222
35.7
5,673
5,098
2033
23.1
3,671
3,297
2.6
405
367
3.3
532
477
1.3
207
187
30.3
4,815
4,328
2034
19.1
3,042
2,732
2.5
393
356
4.8
766
688
1.1
168
152
27.5
4,369
3,927
2035
17.4
2,761
2,480
2.4
381
345
5.6
896
805
1.0
153
138
26.4
4,191
3,767
Note: There will be no production between 2Q 2014 and 3Q 2015. Existing FPSO production will cease in 1Q 2014 with new FPSO production expected from 4Q 2015. Table C.1: Peak oil production forecast for Schiehallion and Loyal Year
Schiehallion existing wells 3
Loyal existing wells
3
mmscfd
sm /day
mmscfd
sm /day
2010
16.1
456,159
2.2
2011
15.7
444,439
2012
20.6
2013
Quad204 Schiehallion 20 infill wells (base case) 3
sm /day
mmscfd
3
sm /day
Total peak gas production rate 3
mmscfd
sm /day
63,156
18.3
519,315
2.3
65,313
18.0
509,752
582,703
3.1
86,953
23.6
669,656
14.2
402,101
2.1
58,487
16.3
460,589
2014
2.0
57,737
0.3
8,932
2.4
66,669
2015
3.7
104,308
0.4
11,946
2.1
60,389
4.5
128,498
10.8
305,141
2016
55.8
1,579,201
6.3
178,877
57.8
1,635,778
5.5
154,451
125.3
3,548,308
2017
39.9
1,130,377
5.9
167,153
50.3
1,423,913
3.4
95,436
99.5
2,816,879
2018
34.4
974,463
5.2
145,955
37.9
1,072,540
4.0
112,419
81.4
2,305,377
2019
28.9
817,264
4.4
124,080
38.0
1,075,093
4.5
128,395
75.7
2,144,832
2020
23.6
667,497
3.7
106,142
37.8
1,070,455
4.1
117,225
69.3
1,961,320
2021
20.7
586,845
3.4
94,933
33.6
952,251
3.1
87,584
60.8
1,721,612
2022
19.0
537,183
2.9
81,268
22.9
649,144
2.5
71,275
47.3
1,338,870
2023
16.3
460,747
2.7
75,227
11.1
312,973
2.1
58,678
32.1
907,626
2024
14.2
403,334
2.4
68,769
6.4
181,084
1.6
46,025
24.7
699,212
2025
12.8
363,360
2.3
64,161
3.3
94,313
1.3
36,828
19.7
558,661
2026
11.7
331,245
2.1
59,756
6.1
173,340
1.2
33,438
21.1
597,779
2027
10.6
299,282
1.8
51,949
2.7
75,456
1.1
31,646
16.2
458,333
2028
9.6
270,656
1.8
49,904
4.1
115,224
1.0
29,709
16.4
465,493
2029
8.8
249,274
1.6
44,287
4.2
119,129
1.3
38,038
15.9
450,727
Page C.2
mmscfd
Quad204 Loyal 5 infill wells (base case)
November 2010
Forecast Production Data Year
Schiehallion existing wells 3
Loyal existing wells
3
Quad204 Schiehallion 20 infill wells (base case) 3
Quad204 Loyal 5 infill wells (base case) 3
Total peak gas production rate 3
mmscfd
sm /day
mmscfd
sm /day
mmscfd
sm /day
mmscfd
sm /day
mmscfd
sm /day
2030
8.3
234,367
1.5
42,055
3.0
84,549
1.3
35,933
14.0
396,905
2031
9.3
264,623
1.4
40,279
2.0
57,734
1.1
32,380
14.0
395,017
2032
12.1
341,492
1.4
39,477
1.5
42,029
0.9
25,486
15.8
448,485
2033
10.9
308,239
1.3
37,774
2.9
83,318
0.8
22,098
15.9
451,429
2034
9.3
264,277
1.3
36,596
3.1
87,710
0.6
18,004
14.4
406,587
2035
7.2
205,239
1.3
35,484
2.6
72,608
0.6
16,433
11.6
329,764
Note: There will be no production between 2Q 2014 and 3Q 2015. Existing FPSO production will cease in 1Q 2014 with new FPSO production expected from 4Q 2015. Table C.2: Peak gas production forecast for Schiehallion and Loyal Year
Schiehallion wells (existing and Q204 infills) 3
Loyal wells (existing and Q204 infills) 3
Total peak produced water rate 3
mbd
m /day
tonnes/day
mbd
m /day
tonnes/day
mbd
m /day
tonnes/day
2010
27.9
4,443
4,554
8.4
1,342
1,376
36.4
5,785
5,930
2011
28.9
4,590
4,705
9.3
1,472
1,509
38.1
6,062
6,213
2012
43.6
6,928
7,101
13.9
2,215
2,270
57.5
9,143
9,371
2013
34.8
5,540
5,678
11.3
1,791
1,836
46.1
7,331
7,514
2014
5.8
929
952
1.8
292
299
7.7
1,221
1,251
2015
5.1
813
834
2.3
370
379
7.4
1,183
1,213
2016
119.0
18,912
19,385
32.4
5,146
5,274
151.3
24,058
24,659
2017
158.2
25,144
25,773
39.4
6,267
6,423
197.6
31,411
32,196
2018
167.7
26,667
27,334
39.8
6,327
6,485
207.5
32,994
33,819
2019
179.4
28,515
29,228
40.6
6,453
6,614
219.9
34,968
35,842
2020
190.3
30,259
31,015
42.5
6,752
6,921
232.8
37,011
37,936
2021
200.0
31,803
32,599
45.6
7,247
7,428
245.6
39,051
40,027
2022
208.3
33,117
33,945
47.4
7,536
7,724
255.7
40,653
41,669
2023
213.3
33,918
34,766
48.8
7,757
7,951
262.1
41,675
42,717
2024
219.5
34,895
35,768
50.0
7,950
8,148
269.5
42,845
43,916
2025
223.8
35,586
36,475
50.9
8,091
8,294
274.7
43,677
44,769
2026
226.9
36,073
36,974
51.4
8,180
8,384
278.3
44,252
45,359
2027
228.2
36,275
37,182
52.0
8,273
8,479
280.2
44,548
45,662
2028
231.2
36,764
37,683
52.4
8,324
8,532
283.6
45,088
46,215
2029
233.7
37,149
38,077
46.9
7,453
7,639
280.5
44,601
45,716
2030
234.2
37,229
38,160
45.4
7,223
7,404
279.6
44,452
45,564
November 2010
Page C.3
Forecast Production Data Year
Schiehallion wells (existing and Q204 infills) 3
Loyal wells (existing and Q204 infills) 3
Total peak produced water rate 3
mbd
m /day
tonnes/day
mbd
m /day
tonnes/day
mbd
m /day
tonnes/day
2031
233.5
37,117
38,044
45.6
7,242
7,423
279.0
44,359
45,468
2032
230.7
36,681
37,598
45.5
7,242
7,423
276.3
43,923
45,021
2033
231.6
36,820
37,741
43.9
6,986
7,160
275.5
43,806
44,901
2034
237.5
37,752
38,696
43.0
6,832
7,003
280.4
44,584
45,698
2035
233.6
37,134
38,062
43.2
6,861
7,033
276.7
43,995
45,095
Note: There will be no production between 2Q 2014 and 3Q 2015. Existing FPSO production will cease in 1Q 2014 with new FPSO production expected from 4Q 2015. Table C.3: Peak produced water forecast for Schiehallion and Loyal
Average production forecast data
Note: There will be no production between 2Q 2014 and 3Q 2015. Existing FPSO production will cease in 1Q 2014 with new FPSO production expected from 4Q 2015. Figure C.1: Average oil production forecast for Schiehallion and Loyal
Year
Schiehallion existing wells 3
Loyal existing wells
3
mbd
m /day
t/day
mbd
m /day
t/day
2010
33.4
5,315
4,773
4.5
714
2011
34.3
5,453
4,897
4.6
2012
46.9
7,463
6,702
2013
34.8
5,536
4,971
Page C.4
Q204 Schiehallion 20 infill wells (base case) mbd
3
m /day
t/day
Q204 Loyal 5 infill wells (base case) mbd
3
m /day
t/day
Total average oil production rate 3
mbd
m /day
t/day
645
37.9
6,029
5,418
733
662
38.9
6,186
5,560
5.9
945
854
52.9
8,408
7,556
4.0
640
579
38.8
6,176
5,550
November 2010
Forecast Production Data Year
Schiehallion existing wells 3
Loyal existing wells
3
Q204 Schiehallion 20 infill wells (base case) mbd
3
m /day
t/day
Q204 Loyal 5 infill wells (base case) mbd
3
mbd
m /day
t/day
mbd
m /day
t/day
m /day
2014
5.3
846
759
0.6
98
88
2015
10.6
1,687
1,515
0.8
132
119
1.1
173
155
0.5
85
2016
94.2
14,971
13,444
9.4
1,502
1,358
4.2
674
606
7.0
2017
75.5
12,006
10,781
7.9
1,251
1,131
5.3
843
757
2018
64.3
10,220
9,177
7.1
1,128
1,020
14.1
2,236
2019
55.2
8,772
7,877
6.0
960
868
19.7
2020
46.3
7,367
6,616
5.1
810
733
2021
43.9
6,977
6,265
4.9
783
2022
36.6
5,812
5,219
4.1
2023
35.4
5,633
5,059
2024
32.2
5,121
2025
28.8
2026
t/day
Total average oil production rate 3
mbd
m /day
t/day
5.9
944
848
77
13.1
2,076
1,866
1,109
1,003
114.8
18,256
16,410
7.1
1,125
1,017
95.8
15,225
13,686
2,008
8.9
1,419
1,283
94.4
15,003
13,488
3,134
2,815
9.3
1,475
1,333
90.2
14,340
12,892
14.6
2,323
2,086
7.7
1,224
1,107
73.7
11,725
10,541
708
11.9
1,897
1,704
5.9
938
848
66.6
10,595
9,525
653
590
7.8
1,243
1,117
4.2
674
609
52.7
8,382
7,535
4.2
672
608
8.5
1,346
1,209
3.7
596
539
51.9
8,248
7,414
4,599
4.0
631
570
6.2
984
883
2.8
453
409
45.2
7,188
6,461
4,586
4,118
3.7
583
527
4.3
676
607
2.1
337
305
38.9
6,182
5,557
28.1
4,469
4,013
3.6
577
522
4.4
696
625
2.0
323
292
38.1
6,065
5,452
2027
24.3
3,856
3,463
2.9
459
415
4.1
651
585
1.7
277
250
33.0
5,244
4,713
2028
24.6
3,914
3,515
3.1
486
439
4.3
676
607
1.8
285
258
33.7
5,361
4,819
2029
22.9
3,641
3,270
2.7
435
393
4.6
728
654
2.2
347
314
32.4
5,152
4,631
2030
20.5
3,266
2,933
2.5
393
355
4.3
680
611
2.0
312
282
29.3
4,652
4,181
2031
22.5
3,584
3,218
2.5
398
360
3.6
578
519
1.8
289
261
30.5
4,849
4,358
2032
23.5
3,729
3,349
2.2
354
320
2.7
437
393
1.3
205
185
29.7
4,726
4,247
2033
21.2
3,377
3,033
2.3
373
337
3.1
489
439
1.2
191
172
27.9
4,430
3,982
2034
17.8
2,826
2,538
2.3
365
330
4.5
711
639
1.0
156
141
25.5
4,059
3,648
2035
16.1
2,565
2,304
2.2
354
320
5.2
833
748
0.9
142
128
24.5
3,894
3,500
Note: There will be no production between 2Q 2014 and 3Q 2015. Existing FPSO production will cease in 1Q 2014 with new FPSO production expected from 4Q 2015. Table C.4: Average oil production forecast for Schiehallion and Loyal
November 2010
Page C.5
Forecast Production Data
Note: There will be no production between 2Q 2014 and 3Q 2015. Existing FPSO production will cease in 1Q 2014 with new FPSO production expected from 4Q 2015. Figure C.2: Average gas production forecast for Schiehallion and Loyal Year
Schiehallion existing wells 3
Loyal existing wells
3
MMscfd
sm /day
MMscfd
sm /day
2010
16.1
456,159
2.2
2011
15.7
444,439
2012
20.6
2013
Quad204 Schiehallion infill wells (base case) 3
sm /day
MMscfd
3
sm /day
Total average gas production rate 3
MMscfd
sm /day
63,156
18.3
519,315
2.3
65,313
18.0
509,752
582,703
3.1
86,953
23.6
669,656
14.2
402,101
2.1
58,487
16.3
460,589
2014
2.0
57,737
0.3
8,932
2.4
66,669
2015
3.7
104,308
0.4
11,946
2.1
60,389
0.3
9,059
6.6
185,702
2016
46.2
1,307,578
5.2
148,111
47.8
1,354,425
4.5
127,885
103.8
2,937,999
2017
32.8
929,170
4.9
137,400
41.3
1,170,456
2.8
78,448
81.8
2,315,474
2018
31.0
877,017
4.6
131,359
34.1
965,286
3.6
101,177
73.3
2,074,839
2019
26.0
735,538
3.9
111,672
34.2
967,584
4.1
115,555
68.2
1,930,349
2020
19.9
564,702
3.2
89,796
32.0
905,605
3.5
99,173
58.6
1,659,277
2021
18.7
528,747
3.0
85,534
30.3
857,978
2.8
78,913
54.8
1,551,173
2022
15.5
439,416
2.3
66,477
18.8
530,999
2.1
58,303
38.7
1,095,196
2023
14.7
417,437
2.4
68,156
10.0
283,554
1.9
53,162
29.0
822,309
2024
12.8
361,791
2.2
61,686
5.7
162,432
1.5
41,284
22.1
627,193
2025
11.1
313,579
2.0
55,371
2.9
81,392
1.1
31,783
17.0
482,125
2026
10.8
304,746
1.9
54,976
5.6
159,473
1.1
30,763
19.4
549,957
2027
8.8
249,002
1.5
43,222
2.2
62,780
0.9
26,330
13.5
381,333
Page C.6
MMscfd
Quad204 Loyal infill wells (base case)
November 2010
Forecast Production Data Year
Schiehallion existing wells 3
Loyal existing wells
3
Quad204 Schiehallion infill wells (base case) 3
Quad204 Loyal infill wells (base case) 3
Total average gas production rate 3
MMscfd
sm /day
MMscfd
sm /day
MMscfd
sm /day
MMscfd
sm /day
MMscfd
sm /day
2028
8.8
250,357
1.6
46,162
3.8
106,582
1.0
27,481
15.2
430,581
2029
8.2
231,077
1.4
41,054
3.9
110,432
1.2
35,261
14.8
417,824
2030
7.3
205,306
1.3
36,841
2.6
74,065
1.1
31,477
12.3
347,688
2031
8.6
244,776
1.3
37,258
1.9
53,404
1.1
29,952
12.9
365,391
2032
10.0
284,463
1.2
32,885
1.2
35,010
0.7
21,230
13.2
373,588
2033
10.0
283,580
1.2
34,752
2.7
76,653
0.7
20,330
14.7
415,314
2034
8.7
245,514
1.2
33,997
2.9
81,483
0.6
16,726
13.3
377,720
2035
6.7
190,667
1.2
32,964
2.4
67,453
0.5
15,266
10.8
306,351
Note: There will be no production between 2Q 2014 and 3Q 2015. Existing FPSO production will cease in 1Q 2014 with new FPSO production expected from 4Q 2015. Table C.5: Average gas production forecast for Schiehallion and Loyal
Note: There will be no production between 2Q 2014 and 3Q 2015. Existing FPSO production will cease in 1Q 2014 with new FPSO production expected from 4Q 2015. Figure C.3: Average produced water forecast for Schiehallion and Loyal
Year
Schiehallion wells (existing and Q204 infills) 3
Loyal wells (existing and Q204 infills) 3
Total average produced water rate 3
mbd
m /day
tonnes/day
mbd
m /day
tonnes/day
mbd
m /day
tonnes/day
2010
27.9
4,443
4,554
8.4
1,342
1,376
36.4
5,785
5,930
2011
28.9
4,590
4,705
9.3
1,472
1,509
38.1
6,062
6,213
2012
43.6
6,928
7,101
13.9
2,215
2,270
57.5
9,143
9,371
November 2010
Page C.7
Forecast Production Data Year
Schiehallion wells (existing and Q204 infills) 3
Loyal wells (existing and Q204 infills) 3
Total average produced water rate 3
mbd
m /day
tonnes/day
mbd
m /day
tonnes/day
mbd
m /day
tonnes/day
2013
34.8
5,540
5,678
11.3
1,791
1,836
46.1
7,330
7,514
2014
5.8
929
952
1.8
292
299
7.7
1,221
1,251
2015
5.1
813
834
2.3
370
379
7.4
1,183
1,213
2016
98.5
15,659
16,050
26.8
4,261
4,367
125.3
19,920
20,418
2017
130.0
20,668
21,185
32.4
5,151
5,280
162.4
25,820
26,465
2018
151.0
24,000
24,600
35.8
5,694
5,837
186.8
29,695
30,437
2019
161.4
25,664
26,305
36.5
5,807
5,953
197.9
31,471
32,258
2020
161.0
25,599
26,239
35.9
5,713
5,855
196.9
31,311
32,094
2021
180.2
28,655
29,371
41.1
6,530
6,693
221.3
35,185
36,064
2022
170.4
27,090
27,767
38.8
6,164
6,318
209.2
33,254
34,085
2023
193.3
30,730
31,498
44.2
7,028
7,204
237.5
37,758
38,702
2024
196.9
31,301
32,084
44.9
7,131
7,309
241.7
38,432
39,393
2025
193.2
30,710
31,478
43.9
6,983
7,157
237.1
37,693
38,636
2026
208.7
33,187
34,016
47.3
7,525
7,713
256.1
40,712
41,730
2027
189.8
30,181
30,936
43.3
6,883
7,055
233.1
37,064
37,991
2028
213.9
34,007
34,857
48.4
7,700
7,892
262.3
41,707
42,749
2029
216.6
34,437
35,298
43.5
6,909
7,081
260.1
41,346
42,379
2030
205.1
32,613
33,428
39.8
6,327
6,486
244.9
38,940
39,914
2031
215.9
34,333
35,191
42.1
6,699
6,866
258.1
41,032
42,058
2032
192.2
30,555
31,319
37.9
6,032
6,183
230.1
36,588
37,502
2033
213.1
33,874
34,721
40.4
6,427
6,587
253.5
40,301
41,309
2034
220.6
35,071
35,948
39.9
6,347
6,506
260.5
41,418
42,454
2035
217.0
34,498
35,360
40.1
6,374
6,533
257.1
40,872
41,893
Note: There will be no production between 2Q 2014 and 3Q 2015. Existing FPSO production will cease in 1Q 2014 with new FPSO production expected from 4Q 2015. Table C.6: Average produced water forecast for Schiehallion and Loyal
Page C.8
November 2010
EIA Matrices
Appendix D EIA Matrices Residual Probability/Frequency Residual Impact/Significance
Residual Consequence
Final
Significance
Stakeholder
Frequency/Probability
Regulatory
Environmental
Planned or Unplanned
Consequence
Well Location and Design
Physical presence of Schiehallion and Loyal well location and drill centre layout
Interference with other sea users and seabed
P
1
2
2
2
5
10 No new drill centres as part of Schiehallion/Loyal. All new wells within existing drill centres and footprint.
1
3
3
Well Location and Design
Physical presence of other BP (e.g. Alligin) and 3rd Party Tie-ins and new drill centres
Interference with other sea users and seabed
P
1
3
3
2
5
15 Routine consultation and notifications.
2
4
8
Process
Activity
Aspect
Mitigation and Comment
Well Design
Water production
Increased water production and associated discharges (see FPSO)
P
3
2
2
2
4
8
Well design to minimise potential aquifer breakthrough.
2
4
8
Well Design
Sand production
Sand production and associated discharges (see FPSO)
P
3
2
2
2
4
8
Well and completion design to minimise sand breakthrough. Can monitor wells for sand production - 2 well probes on all new wells. Understanding in place of which existing wells are sand producers.
4
8
Drilling
Drilling top hole section
Discharge of WBM and cuttings
P
2
2
2
2
4
8
Top hole drilling with low risk chemicals. Post drilling surveys @ Schiehallion and Loyal indicate minimal accumulation of top hole cuttings. Multi-lateral drilling possible for 1-2 wells with associated reduction in tophole drilling.
2
4
8
Drilling
Drilling top hole section (well construction)
Use and discharge of chemicals
P
3
3
2
3
3
9
Chemiclas selection criteria. Top hole drilling with low risk chemicals.
2
3
6
Drilling
Drilling top hole section (well construction)
Oil and chemical spill risk
UP
3
3
3
3
3
9
2
2
4
Drilling
Drilling deep-hole sections
Accidental release of OBM
UP
3
3
3
3
3
9
2
2
4
Drilling
Drilling deep-hole sections
2
2
2
2
4
8
2
4
8
Drilling deep-hole sections
Disposal of OBM contaminanted cuttings to shore - onshore treatment and disposal to landfill Treatment of OBM cuttings offshore (e.g. Rotamill) and discharge of cleaned cuttings to water column. Discharge of oily water and chemicals offshore.
P
Drilling
P
2
2
2
2
4
8
Contractor selection, quality management and equipment maintenance, training and environmental awareness. Contractor selection, quality management and equipment maintenance, training and environmental awareness. Contractor selection, quality management and equipment maintenance, training and environmental awareness. Contractor selection, quality management and equipment maintenance, training and environmental awareness.
2
4
8
Drilling
Drilling deep-hole sections
UP
3
3
3
3
3
9
3
2
6
Drilling
Drilling reservoir section
UP
2
2
2
2
4
8
2
3
6
Drilling
Well blow-out
Treatment of OBM cuttings offshore (e.g. Rotomill) and discharge overboard. Oil and chemical spill risk. Treatment and discharge of hydrocarbon contaminated cuttings, oil and chemical spill risk. Oil spill risks
UP
5
4
5
5
3
1
5
Dril cuttings
Creating cuttings piles on the seabed
P
2
3
2
2
2
15 Contractor selection, quality management and equipment maintenance, training and environmental awareness, OPEP and procedures. 8 There are strong currents in the Quad 204 area tha tensure rapid dispersion thereby minimising potential impacts. No accumulation of cuttings piles is expected. Results of seabed surveys at Schiehallion have demonstrated that there are no significant long-term cumulative impacts.
5
Drilling
2
1
2
Well Construction
Cementing
Discharge of chemicals, chemical spill risk
UP
2
2
2
2
4
8
A PON 15B (permit required under Offshore Chemical Regulations 2002) will be requested for chemical use and discharge. At this stage, exact chemicals to be used/discharged are unknown, but chemical selection process will ensure that chemicals with least environmental impact are adopted. Good drilling practice and procedures.
1
2
2
Completion Design
Selection of downhole completions e.g. gravel pack or flexible screens.
Chemical use and spill risk
UP
3
3
3
3
3
9
BP DPU using flexible screen technology
2
3
6
Well Clean-up
Well clean-up prior to handover to operations (from MODU)
Discharge of chemicals
P
2
2
2
2
4
8
Chemiclas selection criteria.
2
3
6
Well Clean-up
Well clean-up prior to handover to operations (from MODU)
Discharge of visibly oil free water to sea
P
2
2
2
2
4
8
Implementation of appropriate procedures
1
3
3
Well Clean-up
Well clean-up prior to handover to operations (from MODU)
Onshore disposal of waste (e.g. OPF contaminated material)
P
2
2
2
2
4
8
Implementation of appropriate procedures
1
3
3
Well Test
Well test to flare or production
Resource use and atmospheric emissions
P
2
3
2
2
3
6
No well test to flare, well test via multiphase meters or test separator on FPSO
1
4
4
Workover and Interventions
Isolation and removal of pipework containing hydrocarbon + flushings
Chemical use and discharge
P
2
2
2
2
4
8
1
2
2
Workover and Interventions
Undertaking workover and intervention operations
Chemical spill risk
2
2
4
Drilling Rig
Presence of Drilling Rig and support vessels
Interference with other sea users
2
2
4
Drilling Rig
Presence of Drilling Rig and support vessels
2
2
4
Contractor selection, quality management and equipment maintenance, training and environmental awareness. Only overboard discharge if WBM drilled.
UP
3
3
3
3
3
9
Track records to date indicate that workovers for repair will be infrequent. Good practice and implementation of procedures. Implementation of appropriate procedures.
P
1
1
3
2
3
6
Routine consultation and notifications
Oil and chemical spill risk - small operational spills
UP
3
3
3
3
3
9
UP
4
3
4
4
2
UP
2
2
3
3
4
Drilling Rig
Presence of Drilling Rig and support vessels
Drilling Rig
Presence of Drilling Rig and support vessels
Oil and chemical spill risk - total loss of fuel, mud, chemical inventory (loss of well control - blow out incident) Dropped object risk
Drilling Rig
Anchoring operations
Seabed disturbance
P
2
2
3
2
4
Contractor selection, quality management and equipment maintenance, training and environmental awareness, OPEP and procedures. 8 Contractor selection, quality management and equipment maintenance, training and environmental awareness, OPEP and procedures. 12 Contractor selection, quality management and equipment maintenance, training and environmental awareness, OPEP and procedures. 12 Well programme designed to minimise rig moves.
2
4
8
Drilling Rig
Fuel use and power generation
Resource use and atmospheric emissions
P
2
3
2
2
3
9
Implementation of appropriate procedures.
2
3
6
New drill rig contracts being negotiated. Opportunity to influence selection (environmental) and audits of long term rigs. Waste management and recycling.
2
2
4
2
3
6
2
3
6
1
4
4
2
4
8
Drilling Rig
Operation of drilling rig
Noise emissions - disturbance to marine mammals
P
1
2
2
2
4
8
Drilling Rig
Operation of drilling rig
Solid/general waste disposal - onshore landfill
P
2
2
2
2
4
8
Drilling Rig
Operation of drilling rig
Discharge of oily water (drainage) to sea
P
2
2
2
2
4
8
Drilling Rig
Operation of drilling rig
Organic enrichment from sewage discharges
P
2
1
2
2
4
8
Interference with other sea users
P
2
1
3
2
5
10 No plans to abandon/suspend existing wells. Gas disposal well being monitored.
Well Suspension and Abandonment Presence of well heads
Contractor selection, quality management and equipment maintenance, training and environmental awareness. Discharge within MARPOL guidelines.
3
2
6
2
3
6
Well Suspension and Abandonment Well clean up before suspension
Use and discharge of chemicals, chemical spill risk
UP
2
2
2
2
3
6
No plans to abandon/suspend existing wells. Gas disposal well being monitored.
2
2
4
Well Suspension and Abandonment Vessel presence during suspension operations
Interference with other sea users
P
1
1
3
2
3
6
No plans to abandon/suspend existing wells. Gas disposal well being monitored.
2
2
4
Well Suspension and Abandonment Use of cutting charges during well abandonment procedures
Noise emissions - disturbance to marine mammals
P
2
4
3
4
3
12 No plans to abandon/suspend existing wells. Gas disposal well being monitored.
3
2
6
Figure D.1: Wells and Reservoir EIA Matrix
November 2010
Page D.1
EIA Matrices
Residual Consequence
Residual Probability/Frequency
Residual Impact/Significance 8
2
4
8
2
3
6
Contractors selection procedure
2
3
6
2
3
6
Contractors selection procedure
2
3
6
Environmental
Stakeholder
Final
Design of Subsea facilities
Subsea layout - physical presence
Seabed footprint and interference with other sea users
P
1
2
3
2
5
Design of Subsea facilities
Subsea layout - tie-in of other BP fields (e.g. Alligin) and 3rd party tie-ins - physical presence
Seabed footprint and interference with other sea users
P
1
3
3
2
Construction of Subsea facilities
Transport of subsea equipment
Vessel traffic, energy use and emissions
P
2
3
2
Installation of Subsea facilities
Installation and support vessel operations
Vessel presence and interference with other sea users
P
1
1
3
Activity
Process
Aspect
Significance
4
Frequency/Probability
2
5
10 Contractor selection, quality management and equipment maintenance, training and environmental awareness, OPEP and procedures. 15 Seabed survey undertaken post installation. Dropped objects recovered as far as practicable.
Regulatory
Planned or Unplanned
Consequence
Mitigation and Comment
Installation of Subsea facilities
Installation and support vessel operations
Oil and chemical spill risk - small operational spills
UP
3
3
3
3
3
9
EMS, recycling. Procedures
3
2
6
Installation of Subsea facilities
Installation and support vessel operations
Oil and chemical spill risk - total loss of inventory
UP
4
3
4
4
2
8
3
1
3
Installation of Subsea facilities
Installation and support vessel operations
Noise emissions - disturbance to marine mammals
P
1
3
2
2
3
6
2
3
6
Installation of Subsea facilities
Installation and support vessel operations
Solid/general waste disposal - onshore landfill
P
2
2
2
2
3
6
Contractor selection, quality management and equipment maintenance, training and environmental awareness, OPEP and procedures. Appropriate steps (such as operation being of short term, etc.) will be taken to reduce underwater noise. Waste management and contractor selection.
2
3
6
Installation of Subsea facilities
Installation and support vessel operations
Discharge of oily water (drainage and bilge) to sea
P
2
2
2
2
3
6
2
3
6
Installation of Subsea facilities
Installation and support vessel operations
Organic enrichment from sewage discharges
P
2
2
2
2
3
6
1
3
3
Installation of Subsea facilities
Dropped objects
Seabed and habitat disturbance, interference with other users, oil spill risk
UP
2
2
3
3
3
9
Implementation of appropriate procedures. Potential oily discharge to sea will be covered on an OPPC Permit. Contractor selection, quality management and equipment maintenance, training and environmental awareness, OPEP and procedures. Dischage in accordance with MARPOL Dropped objects recovered as far as practicable. Dropped objects study undertaken.
2
2
4
Installation of Subsea facilities
Anchoring operations
Seabed and habitat disturbance
P
2
2
3
2
3
6
2
2
4
Installation of Subsea facilities
Engines and power generation
Resource use and atmospheric emissions
P
2
3
2
2
3
6
2
2
4
Installation of subsea facilities
Seabed survey (geophysical)
Noise emissions - disturbance to marine mammals
P
2
4
3
4
3
3
2
6
Installation of subsea facilities
Impact piling of manifolds
Noise emissions - disturbance to marine mammals
P
2
4
3
4
3
12 Keep to short duration, use latest methodology, planned timing, contractors selection
3
3
9
Installation of subsea facilities
Installation of Xmas Trees and Manifolds
Seabed and habitat disturbance + debris loss
P
2
2
3
2
3
6
As above
2
3
6
Installation of subsea facilities
Installation of flowlines/umbilicals
Seabed and habitat disturbance + debris loss
P
2
2
3
2
3
6
As above
2
3
6
As above
JNCC guidelines. Increased mooring load may lead to slightly wider mooring anchor placement. New moorings being installed from scratch. Old anchors being left behind on (under) seabed. Should be largely within existing footprint. New suction anchors will not protrude above mud-line.
Other options to be considered by JPK. Pile driving Environmental Management Plan now preferred by JNCC. 12 Appropriate steps (such as operation being of short term, etc.) will be taken to reduce underwater noise.
Installation of subsea facilities
Flowline/umbilical protection - mattresses/ rock dumping/ trenching
Seabed and habitat distrubance
P
2
2
2
2
3
6
2
3
6
Installation of FPSO
Physical presence of moorings and risers re. their location
Footprint and interference with other sea users
P
2
2
3
2
5
10 HOCNS and regulatory framework.
2
3
6
Installation of FPSO
Mooring and riser installation
Seabed and habitat distrubance
P
2
2
2
2
2
4
JNCC guidelines. Good practice procedures.
2
1
2
Installation of FPSO
Vessel presence
Vessel presence and interference with other sea users
P
1
1
2
1
2
4
Routine consultation and notifications
1
1
1
Installation of FSPO
Geological Survey for new anchor locations
Noise emissions - disturbance to marine mammals
P
2
4
3
4
2
8
3
2
6
Commissioning of Manifolds, Subsea Pumps etc Commissioning of Flowlines
Hydrotest and leak test
Use and discharge of chemicals
P
2
2
2
2
3
6
Appropriate steps (such as operation being of short term, etc.) will be taken to reduce underwater noise. Contractor selection and pump design specifications.
2
2
4
Hydrotest and leak test
Use and discharge of chemicals
P
2
2
2
2
3
6
2
2
4
Commissioning of Flowlines
Hydrotest and leak test
Spill risk
UP
3
2
2
2
3
Operation of Manifolds and Subsea Physical presence Pumps etc Subsea pump operation Routine operations
Interference with other sea users
P
2
1
3
2
5
Pump barrier fluid needed - protection and lubrication. Fluid leaks across the mechanical seal, back into line and returns to FPSO (mineral water). 6 Contractor selection, quality management and equipment maintenance, training and environmental awareness, OPEP and procedures. 10 Mitigation against potential leakages includes appropriate buffering.
Noise emissions - disturbance to marine mammals
P
1
3
2
2
5
10 No subsea pumps to be installed as part of the Quad204 Project
1
1
1
Subsea pump operation
Routine operations - emissions
Use and discharge of chemicals
P
2
2
2
2
5
10 No subsea pumps to be installed as part of the Quad204 Project
1
1
1
Flowline and umbilical operations
Physical presence
Interference with other sea users
P
2
1
3
2
5
10 Routine consultation and notifications
2
3
6
Flowline and umbilical operations
Discharge of hydraulic fluids (open loop system)
Use and discharge of chemicals
P
2
3
1
2
4
8
Contractor selection, quality management and equipment maintenance, training and environmental awareness, OPEP and procedures.
2
3
6
Flowlines
Accidental damage to flowlines (e.g. fishing impacts)
Oil and chemical spill - loss of flowline contents
UP
4
3
3
4
2
8
2
6
ROV use
Hydraulic oil leaks
UP
3
2
2
2
4
8
Information applied toKingfisher and Fishsafe + communicatiosn with fishing industry. Implemenation of appropriate procedures. Implementation of good procedures.
3
ROV use for SURF activities
2
2
4
UP
3
3
2
3
4
12 Implementation of good procedures.
2
2
4
P
1
1
2
1
3
6
Information applied toKingfisher and Fishsafe + communicatiosn with fishing industry
1
2
2
2
2
4
2
3
6
Inspection and maintenance
Intervention subsea for inspection and maintenance
Leakages / Spill risk
Inspection and maintenance
Vessels presence
Vessel presence and interference with other sea users
Inspection and maintenance
Vessels presence
Atmospheric emissions and waste
P
2
2
2
2
3
9
Implementation of good procedures.
1
3
3
Decommissioning
Removal of subsea facilities
Seabed disturbance and energy use
P
4
3
2
4
2
8
Implementation of decommissioning strategy.
3
2
6
Decommissioning
Removal of flowlines
Seabed disturbance and energy use
P
4
3
2
4
2
8
Implementation of decommissioning strategy.
3
2
6
Decommissioning
Leave in place of subsea facilities
Interference with other sea users
P
4
3
4
4
2
8
Implementation of decommissioning strategy.
4
2
8
Decommissioning
Leave in place of flowlines
Interference with other sea users
P
4
3
4
4
2
8
Implementation of decommissioning strategy.
4
2
8
Decommissioning
Recovered facilities, flowline to shore
Energy use, atmospheric emissions, waste to land, reuse/recycle
P
4
3
4
4
2
8
Implementation of decommissioning strategy.
3
2
6
Figure D.2: Subsea Umbilicals, Risers and Flowlines EIA Matrix
Page D.2
November 2010
EIA Matrices
Environmental
Stakeholder
Final
Frequency/Probability
Significance
Residual Consequence
Residual Probability/Frequency
Residual Impact/Significance
P
2
2
2
2
5
10 Intermittent discharge with PWRI; Chemicals selection process
2
3
6
UP
3
3
3
3
4
12 Contractor selection, quality management and equipment maintenance, training and environmental awareness, OPEP and procedures. Design measures to contain minor spills, e.g. drip trays, tundishes, etc. Spill Kits, operational procedures.
2
3
6
Oily sludges/waste disposal
P
2
2
2
2
4
8
1
2
2
Fugitive gas emissions
P
1
2
2
2
5
10 Captured by LP gas system (see Gas Plant)
2
3
6
Activity
Aspect
Oil Separation Trains
Oil processing
Chemical use and discharge to sea
Oil Separation Trains
Oil processing
Oil and chemical spills - small operational spills
Oil Separation Trains
Oil processing trains - maintenance
Oil Separation Trains
Oil processing
Planned or Unplanned
Process
Regulatory
Consequence
Mitigation and Comment
Waste management procedures
Oil Storage and Export
Oil export - VOC emissions (FPSO)
Atmospheric emissions
P
2
3
4
4
4
16 Hydrocarbon fuel gas blanket. VOC fugitives captured and returned to process.
3
2
6
Oil Storage and Export
Oil export - VOC emissions (shuttle tanker)
Atmospheric emissions
P
2
3
4
4
4
16 VOC recovery will depend on shuttle tanker being used. Loch Rannoch could be retrofitted to have VOC recovery system in the future.
3
2
6
Oil Storage and Export
Oil export hose failure
Oil spill risk - operational spills
UP
3
3
3
3
4
12 Nitrogen purging on export hose to leave the hose sitting dry once exporting complete. Export hose inspection and maintenance programme. Hose design and connections will prevent likelihood of spills. Following discusssions with operatins this is considered an unlikely scenario. Export hoses will be stored on export hose reel with adequate bunding and spills containment connected to drains.
3
2
6
Oil Storage and Export
Crude oil tank and export hose maintenance activities
Oil spills risk - operational spills
UP
3
3
3
3
5
15 Systems to be in place to ensure proper cleaning and containment systems in place to reduce spill risk
3
3
9
Oil Storage and Export
Vessel collision leading to damage to FPSO crude oil tanks
Oil spills - major inventory loss
UP
5
5
4
5
3
15 Contractor selection, quality management and equipment maintenance, training and environmental awareness, OPEP and procedures. Double bottom, double hull FPSO
3
2
6
Produced Water Treatment System Produced water treatment
Chemical use and discharge
P
2
2
2
2
5
10 PWRI - target 95% availability
2
3
6
Produced Water Treatment System Produced water treatment
Fugitive gas emissions
P
1
1
1
1
5
5
1
3
3 6
Captured by LP gas system (see Gas Plant)
Produced Water Reinjection
Unavailability of PWRI system
Discharge of oil to sea
UP
2
2
2
2
5
10 PWRI - target 95% availability
2
3
Produced Water Reinjection
Reinjection of produced water
Resource and energy use
P
2
2
2
2
5
10 PWRI being used as water injection rather than only PW disposal
2
3
6
Produced Water Reinjection
Maintenance of PWRI system
Waste (sand/filters) and disposal
P
2
2
2
2
4
8
1
3
3
Produced Water Reinjection
Maintenance of PWRI system
Off-spec produced water and non-availability of PWRI system
UP
3
2
2
2
3
6
Engineering review of sand production and risks to PW system to improve overall reliability. Cyclones for sand removal. Focus on availability and reliability of PW treatment system. Tank to be used for temporary storage of off-spec PW and then recirculated to PW treatment and reinjection system. Off-spec PW will not be mixed with slops tanks.
2
2
4
Produced Sand
Sand clean-up and disposal
Chemical use and discharge of oily sand overboard
P
2
2
2
2
4
8
Good management of wells e.g. through the use of sand probes in risers, will result in production of less sand. Sand BPEO undertaken.
2
2
4
Gas Plant
Increased flaring levels during commissioning due to non-availability of flare Use of resources and atmospheric emissions gas recovery.
UP
3
3
2
3
4
12 Commission flare gas recovery system early in the programme so that it is ready. Reduce commissioning time.
3
3
9
Gas Plant
Commissioning chemicals
Use and discharge of chemicals
P
2
2
2
2
4
8
Commisioning procedure and chemicals selection process.
2
3
6
Gas Plant
Waste generation - special waste
Use of resources and waste disposal (landfill)
P
2
3
2
2
4
8
Waste management procuderes and use of ENVIROCO (approved waste contractor).
2
3
6
Gas Plant
Gas processing
Chemical use and discharge
P
2
2
2
2
5
10 Chemical selection process.
2
3
6
Gas Plant
Routine operations - atmospheric releases to LP flare
Use of resources and atmospheric emissions
UP
2
2
3
2
4
8
1
2
2
Gas Plant
Maintenance operations - flaring
Use of resources and atmospheric emissions
P
2
2
3
2
4
8
2
2
4
Gas Plant
Shutdowns and Startups - flaring
Use of resources and atmospheric emissions
P
3
2
3
3
4
Review being undertaken of systems that could continue with FGR when other parts of the system are being maintained. 12 Start-up and shut down sequence to minimise emissions. Implementation of appropriate procedures. Vent and Flare Philosophy Flaring will be covered by a consent to flare.
3
3
9
Gas Plant
Gas compressor seals - fugitive emissions
Atmospheric emissions
P
1
2
2
2
5
10 Gas seals on gas compressors - 1st chamber with LP flare and 2nd chamber to vent to atmosphere
2
3
6
Power Generation
Fuel gas use
Use of fuel gas and atmospheric emissions
P
2
2
2
2
5
10 DLE ready GTs will be used.
2
3
6
Power Generation
Commissioning of gas turbines
Use of diesel and atmospheric emissions
UP
2
2
3
2
4
8
Commissioning schedule to minimise reliance on diesel
2
2
4
Power Generation
Non-availability of gas for gas turbines
Use of diesel and atmospheric emissions
UP
2
2
3
2
4
8
Use of low sulphur diesel and efficient turbines.
2
3
6
Power Generation
Turbine washes
Chemical use and discharge
P
2
2
2
2
4
8
Procedures and chemical selection - benign chemical use.
1
2
2
Power Generation
Turbine design and configuration
Energy efficiency
P
2
2
3
2
5
10 CCGT feasibility study and energy efficiency studies being undertaken.
2
4
8
Power Generation
H2S contamination of fuel gas
High SOx emissions
UP
3
2
2
2
4
8
H2S treatment = reduced SOx levels. H2S scavengers - increase in chemical use and discharge.
2
2
4
Small Combustion Equipment
Use of Minor Engines (e.g. emergency generators, key services generator, fire water pumps)
Use of resources and atmospheric emissions
P
2
2
2
2
4
8
Use of electric cranes. Reduce no. combustion engines. Power from turbines.
1
3
3
Flare gas recovery system will remove need for flaring during routine operations.
Figure D.3: Production and Export EIA Matrix
November 2010
Page D.3
EIA Matrices
Regulatory
Stakeholder
Final
Frequency/Probability
Significance
Residual Consequence
Residual Probability/Frequency
Residual Impact/Significance
2
2
2
2
2
4
Outside of Q204 EIA scope. Precommissioning, install, hook-up and tow out to be the subject of a separate scope of work
1
1
1
Chemical use and discharge
P
2
2
1
2
2
4
Implementation of good procedures.
2
1
2
Accidental spill of chemicals
UP
3
3
3
3
2
6
2
1
2
P
1
1
2
1
3
1
1
1
UP
3
3
3
3
4
2
3
6
3
2
6
2
3
6
2
2
4
2
2
4
Aspect
Planned or Unplanned P
Activity
Process
Riser and Mooring Installation
Environmental
Consequence
Mitigation and Comment
Pick-up of laid down risers and moorings. See line item 2.20.
Seabed and habitat disturbance
Riser and Mooring Installation
Connection of risers to FPSO
Riser and Mooring Installation
Connection of risers to FPSO
Riser and Mooring Installation
Presence of FPSO Installation Vessels. See line item 2.21.
Vessel presence and interference with other sea users
Riser and Mooring Installation
FPSO Installation Vessels
Oil and chemical spill risk - small operational spills
Riser and Mooring Installation
FPSO Installation Vessels
Oil and chemical spill risk - total loss of inventory
UP
4
3
4
4
2
Riser and Mooring Installation
Dropped objects
Seabed impacts, interference with other users, oil spill risk
UP
2
2
3
3
4
Riser and Mooring Installation
Operation of FPSO installation vessels
Resource use and atmospheric emissions
P
2
3
2
3
3
Riser and Mooring Installation
Operation of FPSO installation vessels
Noise emissions - disturbance to marine mammals
P
2
3
2
3
3
Riser and Mooring Installation
Generation of waste on FPSO installation vessels
Solid/general waste disposal - onshore landfill
P
2
3
2
2
3
6
Contractor selection, waste management
2
2
4
Riser and Mooring Installation
Discharges from FPSO installation vessels
Discharge of oily water (drainage and bilge) to sea
P
2
2
1
2
3
6
Implementation of procedures. Within MARPOL limits.
2
2
4
Contractor selection, quality management and equipment maintenance, training and environmental awareness, OPEP and procedures. 6 Vessel presence will include tugs used to tow FPSO on station. Tugs will remain holding FPSO in place until all moorings and risers are reconnected. 12 Contractor selection, quality management and equipment maintenance, training and environmental awareness, OPEP and procedures. 8 Contractor selection, quality management and equipment maintenance, training and environmental awareness, OPEP and procedures. 12 Seabed survey will be undertaken post installation. Dropped objects will be recovered as far as practicable. Dropped objects study undertaken. 9 Vessel presence will include 4 tugs used to tow FPSO on station. Tugs will remain holding FPSO in place until all moorings and risers are reconnected. 9 Appropriate steps (such as operation being of short term, etc.) will be taken to reduce underwater noise.
Riser and Mooring Installation
Discharges from FPSO installation vessels
Organic enrichment from sewage discharges
P
2
2
1
2
3
6
Within MARPOL limits
1
2
2
Riser Commissioning
Riser hydrotest and leak test
Chemical use and discharge
P
2
2
2
2
2
4
Chemicals selection process
1
1
1
Riser Commissioning
Riser hydrotest and leak test
Accidental spill of chemicals
UP
3
3
3
3
2
6
Commissioning procedures, training
2
2
4
Commissioning
Presence of Flotel
Increased sewage/domestic stuff during commissioning
P
2
2
1
2
3
6
Discharge within MARPOL limits
1
2
2
FPSO Hull
Antifouling
Leaching of antifoulant to environment - chemical use and discharge
P
2
2
1
2
5
10 Silicon coating considered more environmentally friendly than TBT coating currently on Schiehallion FPSO.
1
2
2
FPSO Thrusters
Installation of thrusters
Noise emissions - disturbance to marine mammals
P
1
3
3
2
5
10 Thrusters will not be used all the time.
2
3
6
FPSO Seawater Intakes
Treatment of seawater intakes
Treatment of seawater intakes with hydrochlorite - chemical use and discharge
P
2
2
2
2
5
10 Chemicals selection process
2
3
6
FPSO Chemicals
Chemical use and storage areas
Chemical spills
UP
3
3
3
3
4
12 Design of chemical storage areas to include adequate bunding/solid deck areas to minimise spills to sea (bunding to contain 110% of volume of the largest tank and designed to withstand FPSO motion)
2
2
4
FPSO Chemicals
Chemical storage - bunkering operations
Chemical spills
UP
3
3
3
3
4
12 Bunkering reels for all hoses
2
3
6
FPSOS Gas Plant and Turbines
Gas Plant and Turbine Chemical Injection
Chemical storage and transfer - chemical spills
UP
3
3
3
3
4
12 Use of a centralised chemical injection area for injection skids to reduce spill risk areas on FPSO. Designated bunded areas with overhead protection to prevent bunds filling up with water. Bunded areas for chemicals in tote tanks.
2
3
6
FPSO Diesel
Diesel bunkering operations
Oil spills
UP
3
3
3
3
4
12 Bunkering reels for all hoses; hard piped hose connections, procedures in place
2
3
6
FPSO Diesel
Storage and transfer of diesel to day tanks
Oil spills
UP
3
3
3
3
4
12 Minimise areas for diesel transfer. Use of permanent piping for transfer to day tanks. Design provides overflow provisions.
2
3
6
FPSO Diesel
Transfer of diesel to temporary equipment
Oil spills
UP
3
3
3
3
4
12 Utility stations for temporary equipment with diesel points running to them. Diesel points will help avoid having to use temporary hoses.
2
3
6
FPSO Diesel
Cargo tanks
Fugitive emissions
FPSO Deck Area and Scuppers
Water run-off
Oil and chemical spills to sea
P
1
2
2
2
5
10 Emissions monitoring.
2
3
6
UP
3
3
3
3
4
12 Cambered decking. Scuppers design. Grated decks on process decks.
2
3
6
10 OWS to meet MARPOL for the voyage, then isolate and when on station all bilge water will go to slops 10 Slop tanks collect tank washings and drainage water from open drains areas. Slops left to settle and then water discharged overboard (15 ppm).
1
3
3
1
3
3
FPSO Machinery Space
Machinery space treatment and disposal
Discharge of oily water (drainage and bilge) to sea
P
2
2
2
2
5
FPSO Slops
Treatment of slops and disposal overboard
Discharge of oily water (drainage and bilge) to sea
P
2
2
2
2
5
FPSO Turret
Turret connections - leaks from the turret can enter the Moonpool
Oil and chemical spills to sea
UP
3
3
3
3
4
12 Implementation of procedures.
2
2
4
FPSO Turret
Oil and gas production fluids
Fugitive emissions
FPSO Ballast tanks
Use of hydraulic pumps and values in ballast tanks
FPSO Accommodation Area
Domestic chemicals
Loss of hydraulic oil through pumps into ballast water (seawater) which is then discharged Chemical use and discharge
P
1
2
2
2
5
10 Good design practice.
1
3
3
UP
2
2
1
2
5
10 Monitoring.
2
3
6
P
1
2
1
1
5
10 Chemical selection process.
1
4
4
FPSO Accommodation Area
Domestic waste
Resource use, landfill and vessel emissions (ship back to shore)
P
2
2
2
2
5
10 Focus on waste minimisation and reuse/recycling
1
3
3
FPSO Accommodation Area
Grey Water/Sewage
Organic enrichment from sewage
P
1
2
1
1
5
5
1
2
2
FPSO Accommodation Area
Galley/Food Waste
Organic enrichment from macerated food waste
P
1
2
1
1
5
5
Sewage treatment plan and holding tank provided. Discharge within MARPOL guidelines ( max. flow rate 5.0m3/hr) Within MARPOL guidelines.
1
3
3
FPSO Accommodation Area
Fire Protection System
Chemical use and discharge
P
2
2
1
2
4
8
1
2
2 2
FPSO Accommodation Area
Refrigerants
Fl GHG and Ozone Depleting Substances - use and discharge
P
2
3
2
2
4
8
Includes testing of fire protection system. No PFC to be used. Aqueous film forming foam (AFFF) to be used. Deluge water to be sea water. No ODS will be used.
2
1
FPSO Laboratory
Laboratory chemicals - use and disposal
Chemical use and discharge
P
2
2
1
2
4
8
Used oil samples to be returned to process. Chemicals collected and disposed of onshore.
2
2
4
Logistics
Supply boats
Interference with other sea users, energy use and emissions
P
2
3
2
2
3
6
Contractor procedures.
2
2
4
Logistics
Helicopters
Noise, energy use and emissions
P
2
3
2
2
3
6
Contractor procedures.
2
2
4
Logistics
Standby vessel
Interference with other sea users, energy use and emissions
P
2
3
2
2
3
6
Contractor procedures.
2
2
4
Decommissioning
Removal of Biofouling when FPSO eventually removed
Waste disposal of biofouling
P
2
2
3
2
3
6
Contractor procedures.
2
2
4
Decommissioning
Reuse or disposal of FPSO
Waste and resource use
UP
3
3
3
3
3
9
FPSO reuse opportunities high compared to other development options (e.g. fixed platform). End of life reuse was aspect considered in concept selection.
2
2
4
Figure D.4: FPSO and Utilities EIA Matrix
Page D.4
November 2010
Commitments Register
1 - Introduction
HSE
BP and its Partners are committed to conducting activities in compliance with all applicable legislation and in a manner which contributes to BP’s stated goals of “no accidents, no harm to people and no damage to the environment”
1 – Introduction
EMS
During operations, the Quad204 development will conform to the requirements of the Environmental Management System (EMS) established for the BP North Sea Strategic Performance Unit (SPU), which is accredited to ISO 14001
1 - Introduction
Future development
Any future development associated with the Alligin field will be subject to a separate EIA process and presented as an addendum to this ES
1 – Introduction
Enhanced oil recovery
A polymer flood enhanced oil recovery (EOR) scheme is currently being evaluated. If EOR is implemented an addendum will be made to this ES at the appropriate time, if required
2 - Alternatives
Produced water
Produced water and its associated chemicals will be routinely re-injected into the reservoir. The PWRI system will be designed to meet a minimum availability of 95% and a target availability of 98%. The target maximum dispersed oil in water concentration will be 15 mg/l
2 - Alternatives
Drainage water
The target maximum dispersed oil in water concentration will be 15 mg/l
2 - Alternatives
Sand disposal
Cleaned sand will be discharged to sea in slurry form with the use of BAT to minimise the oil on sand content to less than 10,000 mg/kg
2 - Alternatives
Atmospheric emissions
Hydrocarbon gas blanketing of the cargo oil tanks will allow recovery of the tank vapours during offloading to limit Volatile Organic Compound (VOC) emissions
2 - Alternatives
Atmospheric emissions
Shuttle tankers with VOC recovery systems will be used
2 - Alternatives
Power generation
The turbines will be of high efficiency and able to be fuelled using either fuel gas (normal operation) or low sulphur diesel. The turbines will be installed “Dry Low Emissions (DLE) ready”. Future implementation of DLE technologies will be assessed in line with technology readiness and legislation at the time of major overhauls of the turbines
November 2010
Operations
Mitigation or management action
Hook-up and commissioning
Issue
Drilling/ Installation
ES section
Detailed design
Project phase
Future Considerations
Appendix E Commitments Register
Page E.1
2 - Alternatives
Flaring
A full flare gas recovery system will be installed, therefore flaring is not expected during normal operating conditions
2 - Alternatives
Decisions outstanding
Environmental impact assessment will continue to be an element of the decision-making process for decisions outstanding
3 – The Development
Drill cuttings
WBM cuttings from the top hole section will be discharged to the seabed. WBM cuttings from the middle hole sections will be discharged from the mobile drilling rig into the sea following cuttings cleaning and mud recovery operations. OBM cuttings will be shipped to shore for treatment and disposal
3 – The Development
Manifolds and subsea trees
Manifolds and subsea trees will have ‘fishing friendly’ integral protection structures which will minimise the impacts of damage to or from fishing gear and protect them from damage by dropped objects
3 - The Development
Decommissioning
A decommissioning programme will be developed in line with regulations and practices in place at the time of decommissioning
5 - EIA Process
Consultation
Consultation with stakeholders will continue beyond the submission of this Environmental Statement
6 – Physical Presence
Seabed impacts
Dynamically positioned vessels will be used for pipelay and piling operations, therefore no anchor mounds will result from SURF and FPSO installation activities
6 – Physical Presence
Seabed impacts
The flowlines and static umbilicals will be surface-laid and not rock dumped, unless to address significant free-spans identified during the post-installation survey
6 – Physical Presence
Seabed impacts
A detailed anchoring pattern will be developed prior to drilling operations to optimise the number of anchor placements required
6 – Physical Presence
Seabed impacts
If concrete mattresses are required, their location will be optimised during design to minimise footprint
6 – Physical Presence
Seabed impacts
All new SURF infrastructure (with the exception of the new mooring line anchors and minor crossovers) will be placed within existing corridors and drill centre locations therefore additional footprint will be minimised
6 – Physical Presence
Interaction with other sea users
BP will ensure that the required consents and notifications are in place and will consult with relevant authorities to avoid interference with Quad204 Project activities at the Schiehallion/Loyal field development
Page E.2
Operations
Mitigation or management action
Hook-up and commissioning
Issue
Drilling/ Installation
ES section
Detailed design
Project phase
Future Considerations
Commitments Register
November 2010
6 – Physical Presence
Interaction with other sea users
A standby safety vessel will continue to operate at the Schiehallion/Loyal field development during Quad204 Project activities
6 – Physical Presence
Interaction with other sea users
Information on new SURF infrastructure will be communicated to other sea users through the standard communication channels including the National Hydrographic Surveyor, Kingfisher bulletins, Notices to Mariners, Admiralty Charts and FishSafe
6 – Physical Presence
Interaction with other sea users
A guard vessel will be present in the area when the existing FPSO is removed from the field until the replacement FPSO is installed
6 – Physical Presence
Dropped objects
Procedures will be put in place to ensure that the location of any lost material is recorded and reported to DECC using PON2 notification and that significant objects are recovered
6 – Physical Presence
Dropped objects
The UK Hydrographic Office will be notified of the location of any unrecoverable objects for use on charts and other nautical publications relevant to the area
7 – Discharges to Sea
Drilling and production chemicals
Environmental risk assessment will be conducted on the use and discharge of chemicals and measures identified to reduce risk as part of the PON15 permitting system. Chemicals with high environmental risk (candidates for substitution) will not be used. An auditable chemical assessment and selection process will be used
7 – Discharges to Sea
Commissioning discharges
Where chemicals are required during subsea installation and commissioning operations, the appropriate risk assessment for the use and discharge of these chemicals will be covered in the PON15 permitting system
8 – Underwater Noise
Underwater noise and disturbance
Use of suction anchors will take preference over pile driving. BP will discuss any pile driving operations with the JNCC
8 – Underwater Noise
Underwater noise and disturbance
Measures to mitigate noise impacts based on the principles of the JNCC guidelines for specific activities (JNCC, 2010) will be implemented. BP will report to JNCC following the end of the activity, detailing the marine mammals sighted, methods used to detect them and details of any problems encountered
9 – Atmospheric emissions
Fuel use and power generation
Fuel use will be minimised throughout design and operation. Emissions from exhaust stacks and metering of fuel gas and diesel fuel rates will be available for each individual turbine
9 – Atmospheric emissions
Energy efficiency
Energy metering systems will be installed and maintained. An energy monitoring and reporting system will be provided
November 2010
Operations
Mitigation or management action
Hook-up and commissioning
Issue
Drilling/ Installation
ES section
Detailed design
Project phase
Future Considerations
Commitments Register
Page E.3
9 – Atmospheric emissions
Well testing
Well testing will not be undertaken at the drilling rig. Testing of producer wells will be undertaken by directing fluids back to the FPSO test separator
9 – Atmospheric emissions
Ozone depleting substances
No ozone depleting substances will be used except hermetically sealed domestic-type appliances (e.g. refrigerators) with an inventory <3kg
9 – Atmospheric emissions
Ozone depleting substances
Refrigeration systems containing CFC or HCFC gases will not be used and refrigerant inventories with least environmental impact will be selected (with reduced ozone depletion potential taking priority over reduced global warming potential)
9 – Atmospheric emissions
Ozone depleting substances
Halocarbon inventories and losses will be recorded annually according to BP Group Reporting Guidelines. Contractors with appropriate licences will be used to maintain equipment containing halocarbons to minimise leaks to the environment
10 – Accidental Events
Spill Prevention & Emergency Planning
Spill response and emergency planning on Quad204 will comply with UK Regulatory requirements and BP corporate requirements. Response plans will reflect lessons learned from previous incidents such as Deepwater Horizon
10 – Accidental Events
Spill Prevention & Emergency Planning
A Quad204 Oil Pollution Emergency Plan (OPEP) will be developed
10 – Accidental Events
Spill Prevention & Emergency Planning
Fuel, oil and chemical storage, handling, transfer and monitoring procedures will be put in place
10 – Accidental Events
Spill Prevention & Emergency Planning
The drill rig will be a semi-submersible drill rig suited to the local environment. It will have a UK safety case and will be class certified by a recognised authority
10 – Accidental Events
Spill Prevention & Emergency Planning
BP will perform assurance audits prior to rig acceptance to confirm all critical systems are fully certified and working as designed
10 – Accidental Events
Spill Prevention & Emergency Planning
Spills will be reported and spill reports will form part of a continuous ‘lessons learned’ cycle
10 – Accidental Events
Oil Spill Response: Coastal
BP have contracted Oil Spill Response Ltd (OSRL) to have strategically located mobile response packages and trained response personnel that can be engaged to combat oil spills approaching inshore areas
Page E.4
Operations
Mitigation or management action
Hook-up and commissioning
Issue
Drilling/ Installation
ES section
Detailed design
Project phase
Future Considerations
Commitments Register
November 2010
11 – Waste Management
Waste Management Policy
In line with BP’s waste management policy the Quad204 Project will apply an approach supported by the waste management hierarchy from project design through to de-commissioning. All efforts will be made to reduce waste at source and to focus on reuse/recycling options for waste generated
11 - Waste Management
Regulatory Control
All wastes will be appropriately classified, segregated, labelled and sorted for safe containment and transportation accompanied by Duty of Care documentation. All waste will be transferred to an appropriately licensed carrier with Waste Carrier Registration / Waste Management Licence or Exemption through the use of bridging documents and audits
11 - Waste Management
Drilling
BP will continue to monitor offshore cuttings treatment technology and potential for installation on contracted semi-submersible drilling rigs
11 - Waste Management
Operational waste
BP will develop a Waste Management Plan (WMP) which will provide a structure for waste guidance and disposal at all stages during the project. Detailed waste management procedures will be developed prior to the operational stage using as a basis the procedures that are currently applied to the Schiehallion FPSO and the BP North Sea Strategic Performance Unit (SPU)
11 - Waste Management
Operational waste
All personnel on BP and contracted vessels used will have received formal waste management awareness training, particularly regarding correct waste segregation, storage and handling of all waste streams
11 – Waste Management
Emergency Response
Emergency response plans will consider waste streams resulting from incidents/ incident response
12 - Environmental Management
Environmental management
The Quad204 Project will conform to the requirements of the Environmental Management System (EMS) established for the BP North Sea Strategic Performance Unit (SPU), which is accredited to ISO 14001 and the scope of the BP Operating Management System (OMS)
12 - Environmental Management
Environmental management
BP requires training for all contractors involved in field operations and will monitor and audit to ensure that they have systems and controls in place to manage their environmental responsibilities
12 – Environmental Management
Environmentally Critical Equipment (ECE)
A register of Environmentally Critical Equipment will be developed and maintained for the Quad204 development. The protective systems associated with these ECE will be identified and the planned maintenance routines for ECE assessed for adequacy. This information will be transferred to operations to ensure that ECE is operated and maintained to a level that achieves objectives and targets, complies with environmental consents and minimises adverse risk to the environment
November 2010
Operations
Mitigation or management action
Hook-up and commissioning
Issue
Drilling/ Installation
ES section
Detailed design
Project phase
Future Considerations
Commitments Register
Page E.5
12 – Environmental Management
Environmental monitoring
Performance measurement for the project will include: Chemical use and dosing rates of chemicals; Drilling mud use; Oil in water levels; Atmospheric emissions; Waste generation; and Spill of oil or chemicals
12 – Environmental Management
Environmental awareness and training
To ensure that on-site project personnel understand the part they play in contributing to environmental protection, BP will ensure training is provided to help raise environmental awareness. This will be delivered through a range of techniques: toolbox talks, poster campaigns, E-learning and formal courses with handson techniques (e.g. spill response)
12 – Environmental Management
Environmental awareness and training
Once operational, the FPSOs standard induction for all personnel arriving onboard will contain an environmental component, incorporating issues which include, but are not limited to, spill prevention, waste and chemical management on the FPSO
12 - Environmental Management
Interface with contractors
All key contractors will be required to meet the intent of ISO 14001 as relevant to their activities
12 - Environmental Management
Interface with contractors
Pre-mobilisation audits (and provision of bridging documentation) of the drilling rig and installation vessels will be undertaken to ensure appropriate procedures, documentation and equipment is in place in order to meet measures identified during the EIA process, BP’s requirements and statutory obligations
12 - Environmental Management
Interface with contractors
Commitments, objectives and targets set for the Quad204 Project will be communicated to contractors, and contractor performance monitored
12 - Environmental Management
Interface with contractors
At the project level all offshore contractors involved in the installation of facilities will be required to produce procedures for all aspects of the installation
12 – Environmental Management
Commitments
The commitments register will be tracked and updated as each element of the project continues into the execution and subsequent operational phases
12 – Environmental Management
Commitments
Mitigation measures identified and commitments made will also be embedded into the following documents to ensure appropriate execution and management: Project basis of design; Detailed engineering specifications; Contracts; Execution plans
12 – Environmental Management
Commitments
Each commitment will be assigned an owner within the Quad204 Project team, and will be reviewed periodically to ensure that it is being met
Page E.6
Operations
Mitigation or management action
Hook-up and commissioning
Issue
Drilling/ Installation
ES section
Detailed design
Project phase
Future Considerations
Commitments Register
November 2010
Summary of the DREAM Model
Appendix F Summary of the DREAM Model Introduction Discharges to sea (see Chapter 7) were modelled using the DREAM (Dose-related Risk and Effects Assessment Model/EIF(Environmental Impact Factor) approach developed from research by SINTEF (The Foundation for Scientific and Industrial Research), TNO (Netherlands Organisation for Applied Scientific Research) and other bodies using well established techniques given in the EU Technical Guidance Document on Risk Assessment (European Commission, 2003). The model incorporates a sophisticated dispersion model using representative metocean data and water current profile in multiple layers for most locations in the UKCS. The output from the process is an Environmental Impact Factor (EIF). The EIF is a reflection of potential environmental risk and is a measurement of the number of unit water volumes, or areas of seabed, at which there exists a possibility of injury to 5% of the most sensitive species. It is similar to a PEC/PNEC ratio of 1 or greater in each unit volume or area. The unit volume is 100x100x10m 5 of water (10 cubic metres) and 100x100m of 4 seabed (10 square metres). This method is accepted by the Norwegian authorities for the management of produced water and chemical discharges on the Norway Continental Shelf. The technique allows the contributions to the EIF to be compared - for example the relative contribution to risk from chemical toxicity versus uptake of fine sediments by zooplankton. This capability provides useful information when comparing alternative proposed methodologies for reducing environmental risks associated with a discharge: a chemical product can be separated into its constituents and the EIF contribution calculated for each of them. The results of the calculations can then be used to improve the product in terms of replacing those constituents that make the largest contribution to the EIF. Each of the stressors included in the model has been peer-reviewed by a panel of experts involved in the development of the model and the science is discussed in numerous scientific publications quoted on the SINTEF website http://www.sintef.no/Projectweb/ERMS/Reports. The stressors are not limited to chemical toxicity but include other stressors such as physical changes in sediment particle size that are November 2010
correlated with environmental impacts (Smit et al., 2008), again using a 5% risk threshold for an EIF of 1. For drilling discharges, the following stressors are modelled in the EIF approach (Smit et al., 2008): Water column h Chemical stress (toxicity). This is modelled using the EIF based on the PEC/PNEC approach from HOCNF testing taking into account biodegradation and partitioning h Particle stress in the water column. This relates to the uptake of fine solids by zooplankton Sediment h Chemical stress (toxicity) h Burial. Burial effects are taken to start at 6.5mm for a 5% risk level h Change in grain size. Work by Smit et al. (2008) has identified a 5% risk level to sediment biota based on a median grain size change of 0.0527mm h Oxygen depletion. This is related to the % change of integrated oxygen content of pore water over the vertical extent of the active bioturbation layer (integration over 10 cm used) This is considered a more holistic assessment than methods relying on, for example, simply the extent of the cuttings pile. The DREAM model also incorporates some sophistication on modelling recovery of the cuttings pile through reoxygenation and bioturbation processes, acknowledging that the area affected by cuttings deposition will ultimately return to the prevailing habitat over time (Schaaning and Bakke, 2006). Further information about the model is provided below.
Model background DREAM has been developed as a decision support tool for management of operational discharges of complex mixtures to the marine environment. The system has been in continuous development for the past 15 years, with support from StatoilHydro, ENI, Total, ExxonMobil, Petrobras, ConocoPhillips, Shell, and BP. DREAM is integrated with the oil spill model OSCAR within a graphical user interface called the Marine Environmental Modelling Workbench (MEMW). A drilling discharge capability has recently been added to the system. DREAM is a 3dimensional, time-dependent, multiple-chemical Page F.1
Summary of the DREAM Model
Figure F.1: General Schematic of the DREAM Model
transport, exposure, dose, and effects assessment model. Each chemical component in the effluent mixture is described by a set of physical, chemical, and toxicological parameters. Because petroleum hydrocarbons constitute a significant fraction of many industrial releases, DREAM incorporates a complete surface slick model, in addition to the processes governing pollutant behaviour and fates in the water column. The model can also calculate exposure, uptake, depuration, and effects for fish and zooplankton simultaneously with physicalchemical transport and fates.
(Neff et al, 2006; Durell et al, 2006).
General model description
The model is driven by winds and currents either produced by other numerical models, or measured as time series in the region of interest. Global datasets of bathymetry and coastlines are supplied with the system, and can be augmented by the user vis standard GIS and/or ASCII formats.
The model has been evolved over a number of years (Johansen et al, 2000; Reid and Hetland, 2002; Rye et al, 2008; Rye et al, 1998). Governing physical-chemical processes are accounted for separately for each chemical in the mixture, including: h vertical and horizontal dilution and transport h dissolution from droplet form h volatilization from the dissolved or surface phase h particulate adsorption/desorption and settling h bio-degradation h sedimentation to the sea floor The algorithms used in the computations, and verification tests of the resulting code, are presented in Reed et al. (2001). The model has also been verified against field measurements Page F.2
Chemical concentrations in the water column are computed from the time- and space-variable distribution of pseudo-Lagrangian particles. These particles are of two types, those representing dissolved substances, and those representing droplets composed of less soluble chemical components or solid particulate matter in the release. These latter particles are pseudoLagrangian in that they do not necessarily move strictly with the currents, but may rise or settle according to their physical characteristics.
Processes governing the behaviour of pollutants in DREAM are presented in Figure F.1. DREAM focuses primarily on underwater releases, such that surface phenomena are of secondary interest. Oil droplets contained in produced water, for example, may rise to the surface and form a surface slick, such that related processes must also be represented in the model. DREAM uses the same algorithms for these processes as used in the oil spill contingency and response model OSCAR (described in detail in Reed et al., (2001)). The 3-dimensional dynamic near field module for DREAM as well as for the oil spill model OSCAR (Plume-3D), functions as a near-field module for produced water and drilling discharges, as well as November 2010
Summary of the DREAM Model other releases of complex mixtures in an aquatic environment. This module is activated automatically whenever a release is specified to originate under water. Depending on depth and other input parameters, the module automatically computes the near-field plume, and the release of dissolved, solid, and droplet-related pollutants from the plume and into the far field.
The environmental impact factor Development of the Environmental Impact Factor has been guided by the principle that areas of uncertainty should be resolved in favour of protecting the environment and conservative environmental assumptions are invoked e.g. the assumption that the most sensitive species are always present in the vicinity of the discharge. The methodology is therefore conservative in the sense of over-protecting rather than under-protecting the environment. The EIF is not designed to serve as an estimator of impact but as a conservative measure of environmental risk that can be used to quantify the comparative benefit to the environment of alternate management strategies. The EIF method is based on the ratio of an exposure concentration to a no-effect concentration, such that the concentration for each compound discharged into the recipient is compared to a concentration threshold for that compound. When the predicted (modelled) environmental concentration (PEC) is larger than the predicted no-effect concentration (PNEC), there may be a risk of ecological injury. When the PEC is lower than the PNEC threshold, the risk of injury from that single substance is considered to be acceptably near zero. By computing the environmental risk due to each component, and adding the risks as independent probabilities, the total risk at any given spatial point at any given time can be calculated. This provides a quantitative measure of the environmental risks involved when operational discharges (e.g. produced water, drilling mud and cuttings etc.) are released into the sea, and is thus able to form a basis for reduction of impacts in a systematic and a quantitative manner.
The predicted environmental concentration (PEC) The PEC is the three-dimensional and time variable concentration in the recipient caused by the discharge of the produced water. The PEC is calculated for all compounds that are assumed to represent a potential for harmful impact on the November 2010
biota. The calculations are used in the numerical DREAM model. This model is fully threedimensional and time variable. It calculates the fate in the recipient of each compound considered under the influence of: h currents (tidal, residual, meteorological forcing) h turbulent mixing (horizontal and vertical) h evaporation at the sea surface h reduction of concentration due to biodegradation
The predicted no effect concentration (PNEC) The PNEC is the estimated lower limit for effects on the biota in the recipient for a single chemical component or component group. The PNEC value is derived from EC50, LC50 or No Observed Effect Concentration (NOEC) values from laboratory testing of toxicity for each component (or chemical product) in question, where the EC50, LC50 or the NOEC value determined is divided by an assessment factor in order to arrive at the expected chronic PNEC. The assessment factors proposed for deriving PNECchronic values in a marine environment for different data sets were those provided in the European Technical Guidance Document Part II on Environmental Risk Assessment (EC, 2003). A major data collection work has been performed in order to obtain data of sufficient reliability for determination of PNEC values. Different procedures have been selected for determination of the PNEC values for natural constituents in produced water and for added chemicals. For added chemicals, the PNEC values are usually based on the information found in the HOCNF (Harmonized Offshore Chemical Notification Format) scheme. Further details can be found in Johnsen et al., (2000).
EIF for drilling discharges The EIF for drilling discharges is necessarily more complex than that for produced water, since both the water column and the seafloor are involved. There are also additional stress factors beyond toxicity that need to be taken into account, including effects of particles in the water column, changes in particle size on the seafloor, burial, and potential oxygen depletion in the sediments due to bio-degradation of organic components in the discharge. These issues are only mentioned here, and are reviewed in more detail by Rye et al., (2008; 2006), Singsaas et al., (2008), and Smit et al., (2008). Page F.3
Summary of the DREAM Model Environmental risk and the EIF
Potential impact modelling
The EIF for a single component or component group is related to the recipient water volume where the ratio PEC/PNEC exceeds unity. The ratio PEC/PNEC is related to the probability of biological injury according to a method developed by Karman (1994) and also published by Karman and Reerink (1997). When PEC/PNEC = 1, this corresponds to a level at which there exists a possibility of injury to the 5% most sensitive species. Figure F.2 shows the relation between the PEC/PNEC ratio and the probability of injury.
Introduction DREAM / ParTrack modelling has been used in the Quad204 Project to investigate the potential dispersion and impact of three discharges to sea: h Discharge of OBM cuttings from the drilling of 25 infill development wells in Phase 1 of the Quad204 well programme h Discharge of produced water during the unavailability of the PWRI system h Batch discharge of produced sand from the Quad204 FPSO
Figure F.2: Relation between the PEC/PNEC level and the risk level (in %) for injury to biota. Based on Karman and Reerink (1997). PEC/PNEC = 1 corresponds to a level at which there exists a possibility of injury to the 5% most sensitive species
The EIF method has the advantage over other risk assessment methods in that it can calculate risk contributions from a sum of chemicals and/or natural compounds in the recipient. The method does not account for interactions among chemicals. The total risk resulting from all components in a release is calculated by the DREAM model in space and time within the model domain. The resultant 3-dimensional risk fields can then be viewed as a time series risk map. Note that the PEC/PNEC ratios for all individual components in the release may be less than unity, but the cumulative risk from all components may exceed 5%, such that the nominal PEC/PNEC ratio produced by the procedure described above, and representing a conglomerate value for the release, exceeds unity. For the water column an EIF of unity is defined as a water volume of 100 m x 100 5 3 m x 10 m (10 m ) in which there is a risk of injury to the 5% most sensitive species. For a single component, this corresponds to a PEC/PNEC ratio exceeding unity. Similarly a sediment EIF of unity is defined as the sediment surface area equal to 100 m x 100 m (104 m2), or 1 hectare, where the combination of risk probabilities exceeds 5%.
Page F.4
The modelling has in all cases been based on conservative assumptions about the discharge scenarios and as such should be seen as supporting evidence for the impact assessments. It should be noted that modelling presents a prediction of the potential outcome to an activity which is based upon the input parameters chosen (chemical data, mud data, discharge scenario). In the case of the Quad204 modelling it has been necessary to base the modelling for this proposed project on the existing Schiehallion data set and the proposed design for the Quad204 Project. As such this modelling aims to investigate the discharges from the Quad204 Project based on worst case assumptions and predictions.
Metocean data The modelling was carried out utilising 3-D currents generated by The Norwegian Meteorological Institute (DNMI) in Oslo, Norway for the year 1990, and 2-D wind fields taken from the weather logging system on the Schiehallion FPSO over 3 years between 2007 and 2010. These were considered representative of the wind and current conditions that might be encountered in the Quad204 Project Area. The data shows that the currents in this area have a relatively persistent direction towards the NE, with seasonally variant winds; predominately from the south-southwest (SSW), west-southwest (WSW) and west (W) with winds from the east-northeast (ENE) and east (E) more uniformly distributed, although less predominant. Currents in the Quad204 area are influenced by the predominantly southwest (SW) / northeast (NE) water flow in the area, although this becomes less apparent with decreasing current speeds at depth. Currents at the surface are strong at around 0.3 m/s; this may increase up to 1.5 m/s with the arrival of an eddy, which can persist for periods of up to several weeks. Whilst all directions are possible, the current is usually maintained in a north-eastward direction, following the depth November 2010
Summary of the DREAM Model contours (Metoc 2002).
Drilling discharges from the Phase 1 infill development well programme The initial set of simulations were carried out to assess the environmental risks from toxic and nontoxic stressors in the water column and sediment, as well as cuttings deposition layer thickness on the seabed for a typical 4-string Quad204 well. This was followed by simulations to assess these effects for the entire development drilling programme. The wellbore schematics for a typical four casing string Quad204 well are presented in Figure 3.3 and a description of the mud system used in each hole section are described in Section 7.3. A mass balance model was developed to calculate the total volume and tonnage of drill cuttings and water based mud discharged to sea using well and casing design information and mud dilution factors gathered from drilling Schiehallion CP23. Typical generic mud formulations for each hole section were then used to calculate the tonnage of each chemical component discharged to sea for each infill well. The average rate of penetration for each hole section and the time interval between drilling discharges was calculated using time estimates of drilling and completion activities.
A map of the water column time averaged risk is shown in Figure F.3 and a cross section through the vector AB on this map is shown in Figure F.4 These data represent volumes of water affected with an EIF greater than one at some point in the modelled period and does not indicate that the EIF is greater than 1 for the whole model run. The currents in the Quad204 area during the simulation period vary in direction with depth and the affect of this can be seen in the risk map and cross section. The mud and cuttings from the top hole sections are discharged at the seabed where the current is predominantly in a SW direction. This discharge results in a water column risk which remains below 240 m in the water column and is dispersed to the SW and W. The mid hole section is discharged 15 m below the sea surface where the current is predominantly towards the NE. This discharge results in a discontinuous volume of impacted water which is predominantly above 160 m in the water column and dispersed to the NE. The volume of water representing the more than 5% risk to the water column is in the immediate vicinity of the well and below 240 m. There is no impact on the water column that is >5% from the discharge at 15m below the sea surface.
The modelling considered a realistic worst case drilling mud use including the cuttings, barite, bentonite and added chemicals. Heavy metals attached to barite were not included in the modelling as no forecast data was available for their likely levels in the material used at the commencement of the drilling programme. The metals associated with drilling barite are also thought to be of low environmental significance (Neff, 1989). Water column impacts The first impact of the discharge of mud and cuttings will be on the water column as both the discharge at the seabed and the discharge from the drilling rig are released into the water column. The deposition of large particles in the drilling discharge will cause a water column stress in the vicinity of the drilling location as they settle to the seabed resulting in a risk to the water column only in the immediate vicinity of the well. The water column stressors from the discharge of WBM which may cause a stress within the water column away from the immediate drilling location, are predominantly the water soluble chemicals in the mud and any fine material that remains suspended. November 2010
Figure F.3: Geographical extent of the impact of cuttings discharge on the water column from a single Quad204 Phase 1 infill well
Page F.5
Summary of the DREAM Model
Figure F.4: Vertical extent of impact of the cuttings discharge on the water column
when the water is not impacted between the drilling of the 42”/36” and 26” sections. The maximum momentary water column EIF is 756, which is equivalent to a maximum volume of water impacted where the risk exceeds 5% of 0.0756 3 km . The potential impact from the cuttings and mud discharges on the water column are expected not to be present when the drilling discharges commence from the 26” section (days 2-3 of the EIF development in Figure F.5), therefore there is unlikely to be any cumulative impact on the discharges from the first section from the
The time for the EIF to develop as the drilling programme progresses is shown in Figure F.5, which shows that the EIF to the water column returns to zero within 7 days of the commencement of the drilling. This also illustrates there is no risk greater or equal to 5% from the discharge of the 17.5” cuttings and mud into the water column and therefore no contribution to the EIF from this section. The development of the EIF in the lower part of the water column from the discharges at seabed are characterised by 4 distinct peaks in its development; including a day
Time development chart of EIF in the water column 42”/ 36” Interval
26” Interval KCl / Polymer mud displacement
800
Seaw ater Bentonite / Gel Sw eeps
700 Cuttings_17_5_Hole Cuttings_26_Hole Barite Bentonite Cuttings_42_Hole MIL-BIO NS MIL-PAC Potassium Chloride SODIUM CARBONATE Xanthan Gum Sodium Hydroxide
600
Weighted EIF
500 400 300 200 100
25
24
23
22
20 21
17 18 19
14 15 16
11 12 13
9 10
8
7
6
5
4
3
2
1
0
0
Time (days)
Figure F.5: Time series of risk for the water column, showing the contribution from each component in the release
Page F.6
November 2010
Summary of the DREAM Model discharge of the second section. In addition the total amount of time when the risk exceeds 5% is predicted to be 6 days over the 25 day simulation period for the water column. The contributions of the various components in the drilling discharge to the EIF are shown in Figure F.6. Over 98% of the EIF risk in the water column is attributable to fine barite and bentonite particles suspended in the water column measured by its potential to interfere with zooplankton feeding. However as most of the EIF is for the suspended solids present in the lower proportion of the water column, the interactions with plankton will be limited. The impact on the water column is therefore predicted to result from the presence of mud particles, barite and bentonite increasing the suspended solids loading of the water column and not as a result of acute toxic impact from the chemicals. The water column impacts are expected to be short term and localised which is in agreement with published impact studies from drilling (1000 fold dilution is expected within 10 minutes of discharge; Neff, 2005). Although there are a number of fish and shellfish that can be found in the vicinity of the Quad204 Project area, the area is not used widely as a fish spawning or nursery area. Therefore there is unlikely to be significant impacts on fish species from the drilling activities. Seabed impacts The modelling showed that 50% of the total
discharged mud and cuttings settled on the seabed within the area of the modelled grid, indicating that this material was widely dispersed. The spatial extent and the thickness of the settled sediment on the seabed are shown in Figure F.7 and the mass balance of the fate of the discharged material is shown in Figure F.8. Figure F.7 shows a wide predicted deposition area, however the layer 2 thickness of 1 mm was limited to 0.616 km . Figure F.8 indicates that over 50% of the release was transported outside the boundaries of the habitat grid used in the simulation (viz, 79 x 76 km). The quantity of material is ca 2150 tonnes, in a water volume of the grid ca 2700 km3 in which the material is dispersing and represents approximately 0.79 ug/l suspended solids concentration. Thus, the resulting effect on oceanic suspended particulate matter concentrations and on sediment layer thickness is likely to be undetectable above background and therefore of low potential for adverse environmental impact. The deposition pattern of the sediment represents the overlapping depositions from the discharge of the top-hole sections at the seabed and their interaction with predominantly SW current at that depth and the discharge from the 17½” section at 15 m below the surface and their interaction with the predominantly NE current at that depth. The component to the south and west comprises the discharges directly at seabed and the settlement to the north and west will result from the heavier material in the discharge at 14m depth in the water column. The sediment impact maps therefore show impact in all directions.
Weighted contribution to risk in the water column, EIF = 756 Potassium Chloride 0.02% Sodium Hydroxide 0.18%
Sodium Carbonate MIL-BIO NS 0.05% 1.29% Cuttings_42_Hole 0.01% Sodium Hydroxide Xanthan Gum Sodium Carbonate Potassium Chloride
Bentonite 45.17%
MIL-PAC MIL-BIO NS Cuttings_42_Hole Bentonite
Barite 53.28%
Barite Cuttings_26_Hole Cuttings_17_5_Hole
Figure F.6: Weighted contribution to risk for the water column, showing the contribution from each component in the release
November 2010
Page F.7
Summary of the DREAM Model
Figure F.7: Extent and thickness of the settled solids on the seabed 60
50
Mass Balance (%)
40
30
20
10
0 Surface
Evaporated
Water Column
Sediment
Ashore
Decayed
Recovered
Outside
Figure F.8: Mass balance of drilling simulation discharge
Page F.8
November 2010
Summary of the DREAM Model
The area of deposition with a layer of sediment greater than 1mm is centred on the well and measures 440 m x 140 m in the SW-NE x NW-SE directions at its maximum extent. The maximum thickness of this area is predicted to be 130 mm in the immediate vicinity of the release point and measures about 30 m across. The potential impact from the settlement of drilling derived solids on the seabed is in agreement with published studies (Neff, 2005, OSPAR 2007) showing localised accumulation of solids near the well position. The model simulation results indicate that the sediment area impacted with a > 5 % probability of a theoretical adverse affect on the most sensitive 2 species present will be approximately 0.0213 km (EIF = 2.13) (Figure F.9). The maximum extent of the >5 % risk zone is approximately 400 m x 115 m across its SW-NE and NW-SE axes respectively, with a maximum risk of between 70% and 87% for a maximum distance of 200m (SW-NE) and 100 m (NW-SE) around the seabed release point. A time development chart for the EIF is shown in Figure F.10. This chart shows that the maximum risk occurs at the cessation of discharge at the end of drilling the 17 ½” hole section (after 18 days drilling). The pie-chart showing the contribution to the EIF (Figure F.11) predicts that the grain size
change (83%) and burial due to sediment thickness (17%) will be the only contributing factors to sediment EIF. There is therefore a negligible contribution from other stressors (e.g. oxygen depletion, toxicity) to the potential impact on the seabed as a result of the discharge from one well.
Figure F.11: Weighted contribution to the sediment risk
Figure F.9: Area of the Seabed with EIF greater than 1 (greater than 5% probability of an affect in the most sensitive species)
November 2010
Page F.9
Summary of the DREAM Model
Time development chart of EIF in the sediment 2.5
Weighted EIF
2 Grain size Oxygen Thickness MIL-BIO NS MIL-PAC Potassium Chloride Sodium carbonate Xanthan Gum Sodium Hydroxide
1.5
1
0.5
3585
3315
3045
2775
2505
2235
1965
1695
1425
885
1155
615
345
92
32
25
23
20
18
16
14
9
11
7
5
2
0
0
Time (days)
Figure F.10: Time series of risk for the sediment, showing the contribution from each component in the release
The impact from the physical deposition of drilling solids is well documented (e.g. Neff, 2005 and OSPAR, 2007) and has been shown to be localised near to the location of the well as indicated in the model results above. It is recognised from research conducted by the dredging industry that the disposal of sediments can adversely impact the benthic community if the sediment structure of the dredged material differs appreciably from the natural sediments at the disposal site. The background sediment grain size that was used in the DREAM model was between 300 and 549 microns and was based upon the geometric means of relevant survey data for the discharge site. The impact from the deposition is not expected to result in major adverse impacts on the seabed other than immediately at the well location. There is likely to be a good potential for recovery of any seabed impacted by sedimentation of drilling solids due to the species present. The potential for recovery from the full drilling programme is discussed below.
Page F.10
Cumulative impacts of the Phase 1 infill well drilling programme The drilling of the 25 infill wells in the Quad204 Project will be conducted over a 6 year period. At the time the modelling was undertaken this Phase 1 drilling was to be conducted at 4 drill centres (Central, North West, West and Loyal), subsequently one of the injection wells was moved to the 5th drill centre at North. The modelling did not consider the 5th drill centre location. As there is a lack of concurrent multi-year metocean data available for the modelling it was necessary to condense the simulation of drilling into a 1 year period to investigate the recovery potential for the seabed. This was achieved by adjusting the well sequence to coincide with the day/month when it is projected it will be drilled within a 1 year period. In addition the restitution of the sediment was evaluated over a 10 year period. The cumulative sediment deposition thickness from the four drill centres is shown in Figure F.12. The maximum sediment layer thickness at each of the drill centres is predicted to range between 310 and 340 mm in depth and cover an area between 25 to 50 m in width. The sediment deposition and risk maps show that there is unlikely to be cumulative impact between drill sites, as the impact is spatially limited.
November 2010
Summary of the DREAM Model
Figure F.12: Map of the deposition profile oh the Quad204 Phase 1 drilling programme overlaid on existing well and survey locations
The cumulative risk map from the simulated phase 1 drilling programme is shown in Figure F.13. The impact from all wells at all sites in the Quad204 phase 1 development have been added together to produce an EIF for the drilling program. The maximum EIF was 31, which is equivalent to a total area of 0.31 km2 from all drill sites together, experiencing a risk of greater than 5% likelihood of impact. The greater than 5% risk zones at each drill centre all extended less than 750 by 300 m across in the SW-NE and NW-SE directions, respectively. Similar to the results from the single 4 string well modelling the Phase 1 modelling predicts that grain size change (79%) and thickness (21%) are the predominant stress factors contributing to the cumulative sediment EIF. When the cumulative impacts of the entire Phase 1 infill well drilling programme were considered by the modelling undertaken, it was necessary, due to the limitation of the model, for the entire programme to occur within 1 year. This very different from the actual duration of this November 2010
programme which is scheduled to occur over 6 years. As such the modelling compounds the impacts of the impact of the phase 1 drilling programme. Size distributions of particulates used in the Quad 204 drilling discharge modelling of the predicted deposition of the drilling mud and cuttings from the phase 1 drilling programme is shown in Figure F.12. This map shows that there is unlikely to be a cumulative impact from the Quad204 phase 1 infill well drilling programme due to the distances between the four drill centres (Central, North, West and Loyal) involved. When this is considered against the longer period of the drilling programme (than simulated by the model) it is highly unlikely that there will be a cumulative impact from the drilling activity. The predicted impact at each of the drill centres considered is similar to that modelled for a singe 4 string well and discussed above. The EIF methodology also provides an estimate of the recovery potential of the sediments to return to normal (background in the model) i.e. the duration Page F.11
Summary of the DREAM Model
Figure F.13: Maximum cumulative sediment EIF for the Quad204 Project Phase 1 infill wells
of the impact on the sediment layer. This restitution time expresses the time needed for the sediment to recover from the impact as defined by the four stressors: burial depth, grain size change, toxicity and oxygen depletion. Assuming that this restitution is the result of natural processes, a number of natural processes will contribute to bring the sediment layer back to original conditions. The processes accounted for in the EIF simulation are: h Biodegradation of organic chemicals in the sediment
depletes the sediment layer for its content of oxygen. Figure F.14 shows cumulative sediment risk maps from one drill site at various time intervals after completing the last infill well. Using the inbuilt model defaults for sediment restoration rates, it is predicted that the seabed is likely to return to its original condition (background modelled) within 4 years. This is representative of all the wells in the Quad204 Project Phase 1 infill well programme.
h Re-suspension and re-distribution of matter on the sea floor h Re-colonization of the biota after disturbance on the sea floor The biodegradation rates are of importance for the restitution of the sediment layer. A large biodegradation rate will reduce the content of organic compounds in the sediment originating from different chemicals added to the mud. The biodegradation also consumes oxygen and thus Page F.12
November 2010
Summary of the DREAM Model
Figure F.14: Snapshots showing sediment risk maps at various time intervals after the cessation of discharge from the last well of the 9 drilled at the Schiehallion West drill centre
There are a variety of timescales for the recovery of benthic sediments from deposition, which will be related to the scale of the deposition and the sediment type and macrobenthic community. Documented recovery times are 1 year from exploratory drilling in Canada (CEAA, 2004); 3 months to more than 2 years at dredge disposal sites (OSPAR 2009).
November 2010
The modelling simulations were carried out assuming the wells were all to be drilled immediately after each other, which is unrealistic. The spacing of the 25 wells throughout the 6 year period will allow some time for recovery of the sediment between impacts. Although this area has received some deposition from the drilling of the Schiehallion wells there will also be time between deposition and the new wells to allow some Page F.13
Summary of the DREAM Model recovery of the sediment from deposition. The time intervals between drilling operations will limit the potential for cumulative impact at the individual drill sites. As the discharges to sea will be separated temporally for all the wells it is very unlikely that there will be cumulative impact on the water column from the drilling discharges.
Produced water discharge during PWRI unavailability In order to model the discharge of produced water it was necessary to devise a scenario in which the total specified annual PWRI down time was modelled as a single occurrence (5% downtime (18.25 days)) which resulted in a continuous discharge from the FPSO. The dispersed oil in water composition of the discharge was calculated from the average values of the last eight biannual analyses taken pursuant to the OPPC consent requirements for the Schiehallion field, from the 2nd half of 2006 to the first half of 2010. In addition this data was extrapolated to the maximum compliance level for dispersed oil in water of 30mg/l to provide the theoretical legal maximum oil in water composition. This approximation was also applied to the heavy metal content of the produced water. In the following text these two scenarios will be referred to as the 9.9 mg/l and 30 mg/l scenarios, respectively. The production chemical package was also considered in the modelling. Four products were included based upon the data in their Cefas templates; a scale corrosion inhibitor (KI-3821), a scale inhibitor (SCALETREAT 8063), a reverse demulsifier (EC6029A) and an H2S scavenger (SCAVTREAT 7103). The concentration of produced water chemicals in the plume after 18.25 days of continuous discharge using the 30mg/l discharge scenario are shown in Figure F.17 and Figure F.18. The plume moves to the north east with the currents and remains in the upper 50 m of the water column. It is rapidly dissipated to give a combined concentration of all components of less that 100 ppb. The resulting risk map for the 9.9 mg/l and 30mg/l and associated cross section from this discharge are shown in Figure F.20.
Page F.14
Produced water components
Concentration (mg/l) Average measured 1 values
30mg/l equivalent
Aliphatic
9.9
30
BTEX
6.861
20.792
Naphthalene
0.513
1.556
Phenols C0-C3 alkylated
0.760
2.302
Phenols C4-C5 alkylated
0.375
1.137
Phenols C6-C9 alkylated
0.193
0.585
PAH 2-3 ring
0.267
0.808
PAH 4-5 ring
0.004
0.011
Copper
0.003
0.009
Zinc
0.038
0.115
Nickel
0.004
0.012
Lead
0.003
0.009
Cadmium
0.0002
0.0007
Mercury
0.0002
0.0007
Note 1: Based on the last 8 biannual produced water samples from Schiehallion Table F.1 Naturally occurring produced water component concentrations used in the DREAM produced water modelling scenarios
The instantaneous EIF values predicted for a continuous discharges lasting 18.25 day are 2170 and 15194 for the 9.9 mg/l and 30 mg/l scenarios, respectively. These are equivalent to a maximum volume of water impacted where the risk of a toxic affect on a sensitive species exceeds 5% of 0.2170 km3 and 1.5194 km3. These values are indicative of a small plume volume where toxicity thresholds are exceeded, and the rapid dissipation of the dissolved chemicals in the plume as it moves away from the point of discharge. The plume is located in the upper 50 m of the water column and would therefore only interact with those species found in this position in the water column, thus reducing the likely impact of the discharge of produced water in reality. Further it is unlikely that this level of impact would be seen in reality as the design of the new FPSO is based on lessons learned from the current Schiehallion FPSO. This improved design should result in lower levels of produced water components and reduced duration and reduced volume of the discharge when compared to that modelled (due to the November 2010
Summary of the DREAM Model buffering of the off spec cargo tank and the improved availability of the PWRI system). The contributions of the various components of the discharge to the 30 mg/l scenario EIF are shown in Figure F.20. This shows that 78.7% of the predicted EIF is related to the alkylphenols with a further 16.0% of the EIF related to the polyaromatic hydrocarbons. The production chemical package contributes less than 0.6% to the predicted EIF. Similar proportional contributions to the EIF are seen for the 9.9 mg/l scenario in Figure F.19.
approximately 30 hours after the discharge ceases in this scenario, as illustrated in Figure F.21. This indicates that the transient nature of the discharges is unlikely to result in any cumulative impact.
Cumulative impacts
9.9 mg/l Scenario
Figure F.15: Water column concentration map for continuous discharge of produced water for 18 days based on the extreme worst case unavailability of PWRI scenario
30 mg/l Scenario
Figure F.16: Water column concentration cross section (along vector in figure) for continuous discharge of produced water for 18 days based on the extreme worst case unavailability of PWRI scenario
Figure F.17: Water column risk map for continuous discharge of produced water for 18 days based on the extreme worst case unavailability of PWRI scenario
The predicted risk in the 9.9 mg/l scenario reduces rapidly after the cessation of the discharge. The risk level reduces to less than 5% in all locations November 2010
Page F.15
Summary of the DREAM Model
9.9 mg/l Scenario
30 mg/l scenario Figure F.18: Water column risk cross section (along vector in figure) for continuous discharge of produced water for 18 days based on the extreme worst case unavailability of PWRI scenario
Page F.16
November 2010
Summary of the DREAM Model EIF_PAH2 0.6%
Contribution to risk, EIF = 2170
EIF_PAH2 0.7% EIF_MERCURY 0.2% EIF_LEAD 0.1%
EC6029A 0.0%
Scaletreat8063 0.0% KI3821 0.2%
Scavtreat7103 1.3%
EIF_ALIFATER 1.2% EIF_BTEX EIF_PHENOL1 0.2% 0.1% EIF_NAPHTHL 0.3% EIF_PAH1 15.7%
EIF_CADMIUM 0.0% EIF_COPPER 1.4% EIF_ZINC 0.7%
EIF_MERCURY 0.2% EIF_LEAD 0.1% EIF_CADMIUM 0.1%
EIF_BTEX EIF_ALIFATER
Contribution to risk, EIF = 15194 Scaletreat8063 0.0% KI3821 0.1%
EIF_COPPER 1.4% EIF_ZINC 0.7%
EIF_PHENOL1 EIF_NAPHTHL EIF_PAH1
EC6029A 0.0%
Scavtreat7103 0.4% EIF_ALIFATER 1.2% EIF_PHENOL1 0.1% EIF_NAPHTHL 0.3% EIF_PAH1 16.0%
EIF_BTEX 0.2%
EIF_PHENOL1 EIF_NAPHTHL EIF_PHENOL2
EIF_PHENOL2 7.0%
EIF_PHENOL3 EIF_ZINC
EIF_PHENOL3 EIF_ZINC
EIF_COPPER
EIF_COPPER
EIF_LEAD
EIF_LEAD
EIF_CADMIUM
EIF_CADMIUM
EIF_MERCURY
EIF_MERCURY EIF_PAH2
EIF_PAH2 KI3821
EIF_PHENOL3 71.0%
EIF_ALIFATER
EIF_PAH1
EIF_PHENOL2 EIF_PHENOL2 6.8%
EIF_BTEX
KI3821
EIF_PHENOL3 71.7%
Scaletreat8063
Scaletreat8063
EC6029A
EC6029A
Scavtreat7103
Scavtreat7103
Figure F.19: The contributions to the EIF of produced water components in the 9.9mg/l scenario
Figure F.20: The contributions to the EIF of produced water components in the 30mg/l scenario
Time development chart 2500 Temperature Scavtreat7103 EC6029A Scaletreat8063 KI3821 EIF_PAH2 EIF_MERCURY EIF_CADMIUM EIF_LEAD EIF_COPPER EIF_ZINC EIF_PHENOL3 EIF_PHENOL2 EIF_PAH1 EIF_NAPHTHL EIF_PHENOL1 EIF_ALIFATER EIF_BTEX
Weighted EIF
2000
1500
1000
500
30
28 29
26
25
23 24
21
20
18 19
16
15
13 14
11
9 10
8
6
4
5
3
0
1
0
Time (days)
Figure F.21: The time development of the EIF of produced water components in the 9.9mg/l scenario
Produced sand batch discharge In order to quantitatively predict the likely deposition of produced sand and to aid in the assessment of the environmental impact of this discharge the water column and sediment models of the DREAM package were used in conjunction to produce a 1 year simulation. The modelled particle size distribution of the sand discharged by the Quad204 FPSO was derived from ongoing Schiehallion operations. An extreme worst case scenario was investigated that assumed 6.625 tonnes of sand containing 1% Schiehallion oil November 2010
Page F.17
Summary of the DREAM Model 3°50'W
3°40'W
3°30'W
4°00'W
3°50'W
3°40'W
3°30'W
60°40'N 60°35'N 60°30'N
60°20'N
60°20'N
60°25'N
60°25'N
60°30'N 365d00:00 4°10'W
Figure F.22: FPSO Sand Discharge Total Sediment Thickness over one year 4°10'W
4°00'W
3°50'W
3°40'W
3°30'W
60°40'N
10 km
60°20'N
60°20'N
60°25'N
60°25'N
60°30'N
60°30'N
60°35'N
60°35'N
60°40'N
The modelling also predicted that the discharge of 1% oil on sand as modelled is unlikely to cause a significant impact on the environment, thus indicating that the lower discharge rates of sand containing a maximum specified 0.15% oil on sand from the new FPSO will also have no predicted impact.
4°00'W
10 km
60°35'N
The sand deposition pattern over 1 year is shown in Figure F.22. 95% of the material discharged remains within 25 km of the release point from the FPSO in a thin layer, with coarser material remaining closer to the release point. This is contrasted by the modelling of the drilling discharges which predicted a layer of sediment greater than 1 mm and centred on the well that measures 440 m x 140 m in the SW-NE x NW-SE directions at its maximum extent was produced with maximum thickness predicted to be 130 mm in the immediate vicinity of the drilling release point. The deposition layer from the sand by contrast is so thin (0.02 mm), and with such low levels of oil, that the EIF is at no point greater than 1 i.e. there is no risk exceeding the 5% level from this discharge, and the risk to the environment is in fact below a level of 0.01. Given normal sediment recovery rates and sediment deposition rates in the area, it is unlikely that long term batch discharge of sand will have significant effect on the sediments in this area.
4°10'W
60°40'N
attached to it, will be discharged in a batch process over 3 hours each week. This scenario is based upon the highest sand production rate and an oil on sand value that is 6.6 times the design specification of the new FPSO and therefore by far the worst case. This discharge scenario however represents a small amount of particulate material when compared to the project discharge from drilling the 25 new Quad204 infill wells of 2900 to 4700 tonnes per well over a 6 year period.
Water Column Risk Map: Total
The risk to the water column over 1 year from the sand discharges is shown in Figure F.23. This map shows a time integrated result where there is limited risk to the water column from the sand discharge, with no EIF value being calculated for the water column as a result of a year of extreme worst case discharges. There is unlikely to be a significant impact from the discharge of produced sand from the Quad204 FPSO.
Page F.18
365d00:00 4°10'W
4°00'W
3°50'W
3°40'W
3°30'W
Figure F.23: FPSO Sand Discharge - Maximum Water Column Risk over 1 Year
November 2010
Atmospheric Emissions Quantification Data
Appendix G Atmospheric Emissions Quantification Data The following sections present the calculations that have been undertaken in order to forecast the Quad204 Project atmospheric emissions. In particular they detail: h Drilling rig and vessel emission calculation data tables, conversion factors and assumptions h Power generation emissions data tables, conversion factors and assumptions
CO2 equivalent emission factors CO2
1
CO
2
NOX
40
N2O
296
SO2
0
CH4
23
VOC
0
Table G.2: CO2e emission factors in tonne/tonne
h Flaring emissions data tables, conversion factors and assumptions
The following assumptions were made in order to forecast drilling rig and vessel emissions:
h VOC emissions data tables, conversion factors and assumptions
h From operating experience BP estimated that a 4th generation semi-submersible drilling rig will use 550 tonnes of diesel per month;
Drilling rig and installation / commissioning vessel emissions
h PI guidelines were used to estimate the following vessel fuel consumption:
Vessels atmospheric emissions factors Tables G.1 and G.2 show the emission factors used to calculate atmospheric emissions for CO2, CO, NOX, N2O, SO2, CH4, and VOC and CO2 equivalent (CO2e) for the drilling rig, installation and commissioning vessels. The Oil & Gas UK Environmental Emissions Monitoring System (EEMS) Atmospheric Emission Calculations document provided the emissions factors for CO2, CO, NOX, N2O, SO2, CH4, and VOC, while the 2001 IPPC guideline the CO2 equivalent (CO2e) factors.
Emissions factors CO2
3.2
CO
0.008
NOX
0.059
N2O
0.00022
SO2
0.004
CH4
0.00027
VOC
0.0024
h safety vessel used for stand-by vessel h multi support vessel used for riser vessel h supply vessel used for an inspection repair and maintenance vessel h drilling rig anchor handling vessels h multi support vessel in transit used for a skip and ship vessel h Three anchor handling vessels will be required to manoeuvre the drilling rig; and Table G.3 presents the information that was used to prepare Figure 9.1. The annual CO2 emissions were calculated using the number of drill rig days, the daily rig fuel use consumption of 18.1 tonnes per day and the drilling rig emissions factor of 3.2.
Table G.1: Emission factors in tonne/tonne diesel fuel
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Page G.1
Atmospheric Emissions Quantification Data
Power generation
Year
Drilling rig days
Drill rig CO2 emissions (t)
2014
308
17,822
2015
523
30,262
2016
518
29,973
2017
629
36,396
2018
365
21,120
2019
365
21,120
NOX
Correlation*
0.0576
0.01724
0.0594
2020
366
21,178
CO
0.003
0.0076
0.00092
0.0157
2021
155
8,969
CH4
0.00092
0.0198
0.0000328
0.00018
NMVOC
0.000036
0.0032
0.000295
0.002
SO2 (LSD)***
0.000193
0.000193
0.002
0.002
SO2 (ULSD)****
0.000193
0.000193
0.00009987
0.00009987
Table G.3: Annual drilling rig CO2 emissions
Table G.4 below informs Figure 9.2. Using the method presented for Table G.3, the peak year (2014) CO2 emissions for vessel activity was estimated using an emission factor of 3.2.
Table G.5 shows the CO2, NOX, CO, CH4, SO2 and VOC emission factors used to calculate the power generation emissions in Tables 9.3 and 9.4 of Chapter 9. Fuel Gas Pollutant
Turbine
Diesel
Engine
Turbine**
Engine
tonne of pollutant per tonne of fuel
Fuel consumption (tonnes/day)
Table G.5: Power generation emission factors CO2 (tonnes)
* Correlation for NOX: EF = 0.000161*(MWth) (assuming aeroderivative generic gas turbine)
15
6,384
** For NOx, using EEMS default factor for aeroderivative gas turbine operating on diesel
133
5
2,128
Anchor handling vessel
186
5
2,976
Standby vessel
365
5
5,840
Survey vessel
20
5
320
Skip and ship vessel
108
18
6,221
Riser vessel
159
18
9,158
Tug
62
5
992
Construction vessel
241
10
7,712
Inspection repair and maintenance vessel
20
5
320
Seismic vessel
56
15
2,688
Diesel
Shuttle tanker
56
7
1,254
Diesel CO2 EF
Vessel days
Reel pipelay vessel
133
Pipelay support vessel
Vessel type
*** SO2 emission factor for fuel gas: SO2 EF = 0.0188 * H2S wt% **** SO2 emission factor for diesel: SO2 EF = 0.02 * S wt%
In conjunction to the above equations, the conversion factors in Table G.6 were used during the calculations.
Fuel Gas
Total
1,539
45,994
Density
0.0203
kg/scf
LHV
49.22
MJ/kg
CO2 EF
2.72
tonne CO2/ tonne fuel gas
3.19
tonne CO2/ tonne diesel
Table G.6: Fuel gas and diesel conversion factors
Table G.4: Peak year (2014) CO2 emissions by vessel activity
Page G.2
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Atmospheric Emissions Quantification Data
Table G.7 informs Figure 9.5 in Chapter 9.
Turbines (fuel gas)
Turbines (diesel)
Miscellaneous diesel
Total
tonnes/yr
tonnes/yr
tonnes/yr
tonnes/yr
2015
253,945
6,575
4,377
264,896
2016
362,203
9,347
4,463
376,013
2017
364,077
9,426
4,377
377,880
2018
363,802
9,420
4,377
377,598
2019
364,077
9,426
4,377
377,880
2020
364,518
9,407
4,463
378,388
2021
364,904
9,446
4,377
378,726
2022
362,975
9,398
4,377
376,749
2023
363,691
9,417
4,377
377,485
2024
365,290
9,426
4,463
379,179
2025
262,874
6,804
4,377
274,055
2026
263,922
6,833
4,377
275,131
2027
261,000
6,756
4,377
272,133
2028
261,937
6,760
4,463
273,160
2029
261,276
6,763
4,377
272,415
2030
260,394
6,740
4,377
271,511
2031
261,000
6,756
4,377
272,133
2032
260,339
6,718
4,463
271,520
2033
260,835
6,753
4,377
271,965
2034
261,496
6,769
4,377
272,642
2035
260,890
6,753
4,377
272,020
Total
6,405,445
165,695
92,341
6,663,481
Year
Table G.7: Breakdown of CO2 emissions (fuel gas and diesel)
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Page G.3
Atmospheric Emissions Quantification Data
Flaring Table G.8 shows the flare incident release rate for one release and over a period of 25 years.
Per release Flare incidents
Rate
Duration
Quantification over 25 years Volume
CO2
no off
mmscf
mmscfd
minutes
hours
mmscf
Tonnes
4 x major release of 220 mmscfd lasting 30 minutes each
220
30
0.5
4.6
-
100
458
8 x compressor trips of 110 mmscfd lasting 20 minutes each
110
20
0.3
1.5
-
200
30 x slug catcher PCV releases of 30 mmscfd lasting 5 minutes
30
5
0.0833
0.1
-
750
Total
CO2
kmol mol wt
kg
Tonnes
547,885
18
9,861,930
9,862
306
365,257
18
65,74,620
6,575
78
93,389
18
1,681,011
1,681
133.7
Total
18,118
Table G.8: Flare incident release rates
Page G.4
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Atmospheric Emissions Quantification Data
Venting
Annual VOC emissions (tonnes/year)
Table G.9 shows the emission factors used to calculate VOC emissions (factors taken from Akhirst, 1997).
Activity
Emission factor (tonnes of VOC per tonne of oil produced)
Production and storage
0.0007
Cargo off-take (no VOC recovery)
0.00028
Cargo off-take (with VOC recovery)
0.000024
Transit
0.000006
Table G.9: VOC emissions factors
Table G.10 informs Figure 9.6 in Chapter 9. The calculations are based upon peak oil production rates (Chapter 3) and the emission factors presented in Table G.9.
Production and storage
Cargo offtake
Cargo transit (assumed to SVT)
Total
2010
1,384
554
12
1,950
2011
1,420
568
12
2,001
2012
1,936
774
17
2,727
2013
1,418
567
12
1,997
2014
217
87
2
305
2015
7
16
4
28
2016
76
174
44
294
2017
64
146
36
246
2018
57
131
33
222
2019
55
125
31
212
2020
48
109
27
185
2021
41
93
23
156
2022
35
81
20
136
2023
31
72
18
121
2024
28
63
16
107
2025
25
56
14
95
2026
23
52
13
88
2027
22
50
12
84
2028
20
46
11
77
2029
19
44
11
74
2030
18
42
10
71
2031
18
41
10
70
2032
20
45
11
76
2033
17
38
9
64
2034
15
34
9
58
2035
14
33
8
56
Year
Table G.10: VOC emissions comparison between Schiehallion and Quad204
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Atmospheric Emissions Quantification Data
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Page G.6
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Summary of Atmospheric Dispersion Model
Appendix H Summary of Atmospheric Dispersion Model ADMS4
In addition, ADMS4 is able to: h calculate long-term concentration statistics, typically for periods of one or more years, for direct comparison with air quality standards and objectives
The information presented below is a summary from the ADMS4 (Atmospheric Dispersion Modelling System Version 4) Users Guide which is available from the CERC website at http://www.cerc.co.uk/environmentalsoftware/ADMS-model.html (accessed 09/09/2010).
h take into account the often very significant effects that a nearby receptor can have on the dispersion of emissions
ADMS4 is a dispersion model used to model the air quality impact of existing and proposed industrial installations as part of environmental impact assessments, IPPC (Integrated Pollution Prevention and Control) authorisations, stack height determination, odour modelling, safety and emergency planning or for other regulatory purposes.
h allow for the effects of complex terrain and changes in surface roughness on wind speed and direction, and on the levels of turbulence in the atmosphere
ADMS4 simulates a wide range of buoyant and passive releases to the atmosphere either individually or in combination of sources. This allows the impacts of emissions from industrial and other facilities to be thoroughly investigated
h model the effect of the sea or ocean on the atmospheric boundary layer
The ADMS4 dispersion model uses two parameters: h the boundary layer height (h) h the Monin-Obukhov length (LMO) to describe the atmospheric boundary layer using skewed Gaussian concentration distribution to calculate dispersion under convective conditions ADMS4 calculates boundary layer information from input of meteorological data; it also calculates long-term and short-term concentrations and dispersion fluxes from continuous point, jet (directional release), line, area and volume sources. Sources can be time varying on an hourly, period or seasonal basis. Emission from these sources may result in buoyant emissions. These buoyant emissions, and those with vertical momentum, rise in the atmosphere after emission. This movement, which is referred to as plume rise, also results in additional dilution and can result in the emission penetrating the top of the atmospheric boundary layer and being lost from the local area. These effects are included in the modelling using an integral solution of the conservation equations for the plume’s mass, momentum and heat. The possibility of entrainment behind the stack, known as downwash, which can lower the effective height of the emission, is also included in the calculation.
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h model the chemical conversions that occur in the atmosphere between nitrogen oxides (NOx), nitrogen dioxide (NO2), nitrogen oxide (NO) and ozone (O3)
h determine the quantities of an emission deposited to the ground by both dry and wet deposition processes
h model dispersion in a 3-D wind and turbulence field h model concentration in units of ou or oue for odour studies h include the decay of radioactive emissions and determine the gamma dose at a location received from passing material h report the extent to which a moist plume will be visible For most situations ADMS4 is used to model the fate of emissions for a large number of different meteorological conditions. Typically, meteorological data are input for every hour during a year or for a set of conditions representing all those occurring at a given location. ADMS4 uses these individual results to calculate statistics for the whole data set. These are usually average values, including rolling averages, percentiles and the number of hours for which specified concentration thresholds are exceeded. This allows concentrations to be calculated for direct comparison with air quality limits, guidelines and objectives, in whatever form they are specified. Results can be presented as numerical values at specified locations. In addition, by calculating concentrations over a grid of locations, results can be presented graphically as concentration contours or isopleths.
Page H.1
