Ghanas Jubilee Gas Export Pipeline Project

saipem

JUBILEE GAS EXPORT PIPELINE PROJECT CONCEPTUAL DESIGN REPORT

Page 1 of 26

Date May 2010

JOB: 045942

00-LA-E-80000 Rev. 1


10/05 /10

1

As noted

UFF TEC

M. FRATTINI (P/L dpt)

G. LANZA (P/L dpt)

23/04 /10

0

Issued for Comments

UFF TEC

M. FRATTINI (P/L dpt)

G. LANZA (P/L dpt)

Date

Revision

Description of Revision

Prepared

Checked

file: 310453835.doc This document is the property of Saipem SpA all rights reserved. Violators will be pursued under civil and criminal law.

Approved

saipem


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Date May 2010

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Revision Summary Approved Date April 2010 MAY 2010

Issue Date -----

Revision No.

Section/Page Revised

0

N/A

Issued for Comments

1

N/A

As noted

Description of Revision


Approved By

saipem


Page 3 of 26

Date May 2010

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CONTENTS 0.

EXECUTIVE SUMMARY

1.

SCOPE

2.

ACRONYMS AND ABBREVETIONS

3.

PROCESS AND UTILITY SYSTEM DESIGN DATA AND CRITERIA

4.

ROUTE SELECTION 4.1.

Description Offshore Pipeline Route

4.2.

Description of 18” pipeline route section from onshore plant to Takoradi plant

4.3.

Description of 12” pipeline route section from onshore plant to Effasu

4.4.

Description of 16” pipeline route section from LTE to onshore plant

4.5.

Proposed location for onshore plant closed to Bonyere

4.6.

Pipeline route findings

4.7.

Onshore pipeline constructability

5.

PROPOSED DESIGN CONFIGURATION 5.1.

Offshore Gas Export Pipeline System Description

5.2.

On shore pipeline Design Configuration

6.

EXECUTION SCHEDULE 6.1.

Onshore pipeline detail design work schedule (site survey, eng, proc, const)

ON SHORE PLANT SCHEDULE (HOLD) 7.

ATTTACHMENTS 7.1.

Steady State Flow Assurance Study (00-ZA-E-08002)

7.2.

On shore Plant Process Report

7.3.

Off-shore Gas export pipelines route map

7.4.

18” Pipeline route map from onshore plant to Takoradi from KP 0.00 to kp 50.00 (00-LCD-81001)

(00-ZA-E-3000)


saipem


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7.5.

18” Pipeline route map from onshore plant to Takoradi from KP 50.00 to kp 132.50 (00-LC-D-81002)

7.6.

12” Pipeline route map from onshore plant to Effasu from KP 0.00 to kp 42.80 (00-LC-D-81003)

7.7.

Map of proposed location for onshore plant near Bunyere (00LC-D-81014)

7.8.

Typical pipelines ROW Design (00-LC-D-81010)

7.9.

Typical ditch dimension

7.10.

Typical main line block valve scheme (00-LC-D-81012)

7.11.

Launcher/Receiver typical layout (00-LC-D-81013)

7.12.

Metering station typical layout

(00-LC-D-81011)


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Page 5 of 26

Date May 2010

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EXECUTIVE SUMMARY General overview of the system A Pipeline Transmission System and Central Processing Facility (CPF) configuration is proposed in this study for the transport and treatment of gas produced from the Jubilee Field, located in the Deepwater Tano (DT) and West Cape Three Points (WCTP) blocks, approximately 60 km offshore Ghana, West Africa. The gas export pipeline will run from the FPSO via a gas export flexible riser and a rigid gas export pipeline to Bonyere. Tie-in facilities are considered between 80 meter and 100 meter water mark location. The fluid is separated and partially treated by FPSO process facilities. Length of the offshore pipeline from FPSO to onshore receiving terminal is approx. 50 km. The offshore pipeline receiving terminal at Bonyere will include a slug catcher, to handle possible slugging, and a CPF to treat the gas. In the CPF the gas will be treated, and LPG, Butane and Propane Fluids will be separated in order to be sold as per market standards. Lean gas, produced by the plant, will be delivered, by means of two pipelines, to Effasu Power Plant and to Takoradi Thermal Plant, with an approximate length of 43 km and 124/132 km (two alternatives are considered for the route to Takoradi) respectively, plus possibly other market users. The gas treatment capacity is 300 MMSCFD during full development. A scheme of the system is shown in Figure 0.1. Offshore pipeline sections The size of offshore pipeline (including 12” sections from FPSOs to tie-in, followed by a 16” section to landfall) was derived from previous pre-engineering studies by INTECSEA; in this study, this size has been verified according to the expected production profile and pressure conditions. It has been verified that the pipeline can transport a maximum flow rate exceeding the target design flow rate, i.e. ultimate flow rate is about 450 MMSCFD. Normal operating condition is with the gas in dense phase. However, possible Off-Spec gas compositions have been analyzed also, and chemical inhibition requirements have been obtained to avoid hydrate issues. Offshore pipeline constructability The construction process of the offshore pipeline is determined by the simultaneous presence of a deep water section and a shallow water one. This leads to the use of a construction vessel able to perform both S-Lay and J–Lay or to the use of two different vessels. Based on a preliminary analysis the offshore pipeline construction process can be summarized as follow:  a pull-in will be performed from shore and then the pipeline laying will start with the S-Lay method till a Water Depth of about 200m where the pipeline will be abandoned;


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After performing the pipeline recovery, the lay process will continue in J-Lay method till PLET abandonment.

The necessity of an above water tie-in will be evaluated in a more detailed analysis based on vessel characteristic and seabed morphology of the shore approach. Onshore pipeline sections Sizing of onshore pipeline has been calculated on the basis of the expected fuel gas consumption at Effasu and Takoradi plants, and considering a maximum operating pressure of 100 barg for the optimized system. Hence, a system composed by a 12” line to Effasu and a 18” line to Takoradi is proposed as onshore configuration. The on shore pipelines routes have been described in chapter 4.0 while the on shore pipeline constructability has been detailed in section 4.8 of this report. The main aspects of constructability are concerning to the pipeline installation equipments suitable both for dry land sections and swamp sections. In swamp section an appropriate overweighing system for all pipelines sections have been designed for the on bottom stability. A site survey should confirm the conceptual design routes selection Consideration on Central Processing Facility (CPF) The offshore pipeline receiving terminal at Bonyere will include inlet facilities (slug catcher, pig receiver) and a Gas Processing Plant. The Gas Processing Plant will be constituted of two trains where the gas will be treated and propane and butane liquids and stabilised condensate will be separated in order to be sold as per market standards. Sales gas, produced by the plant, will be delivered, by means of two pipelines, to Effasu Power Plant and to Takoradi Thermal Plant. Liquid products will be exported from processing plant through pipelines to an offshore export buoy required for mooring off-take tankers. It has been assumed that liquid products will be exported from processing plant through pipelines to an offshore export buoy required for mooring off-take tankers. The development of the Jubilee Field is foreseen to be divided in two steps: the First Phase and the Second Phase (or Final Configuration). The First Phase foresees the installation of one gas treatment unit (one train), where the gas coming from one FPSO will be treated and LPG and condensates will be separated in order to be sold as per market standards. The capacity of plant in this phase is 150 MMScfd of gas to be treated.


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In the Second Phase another train with the same units and the same capacity of the previous one (150 MMScfd) will be installed, in order to treat all the gas coming from the two FPSO’s. Design capacity of plant in final configuration is of 300 MMScfd of gas to be treated. In its final configuration the CPF will then consist of two identical gas treatment trains and common units for the two trains (inlet facilities, liquids storages and metering stations). The CPF will be constituted of the following simplified processing units: 1. Gas Inlet Facilities, comprising slug catcher and pig receiver, to receive the gas coming from FPSO. This unit will be common for the two trains. 2. Gas Dehydration Unit, where water contained in raw gas will be removed. It is foreseen one dehydration unit for each train. 3. Gas HC Dew Point Control, where the gas meets the sales gas specification through low temperature separation and C2 is recovered in a De-Ethaniser. One unit per train will be installed. 4. LPG Recovery Unit, where C3 and C4 and stabilised condensate are recovered. One unit per train will be installed. 5. C3 and C4 Storage and Export units. This unit will be common for the two trains. 6. Stabilised Condensate Storage and Export Units. This unit will be common for the two trains. 7. All the utilities units needed to support with auxiliary fluids will be foreseen in Gas Plant.


JUBILEE GAS EXPORT

saipem

PIPELINE PROJECT CONCEPTUAL DESIGN REPORT

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Date May 2010

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Figure 0.1 : Scheme of Jubilee Gas Transport System - Maximum Bonyere Pressure = 100 barg


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1

Page 9 of 26

Date May 2010

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SCOPE The Jubilee Unit Partners are developing the Jubilee Field situated in the Deepwater Tano (DT) and West Cape Three Points (WCTP) blocks, approximately 60 km offshore Ghana, West Africa. This document deals the conceptual design to define the pipeline transportation system configuration both for the off-shore and on-shore section. The pipeline transportation system is composed of an off-shore 16” sealine (about 60 km), an onshore plant near Bunyere and on shore pipeline system to Taloradi and Effasu locations along the coast of Ghana. The lean gas, produced by the on shore plant, will be delivered, by means of two pipelines, to Effasu Power Plant and to Takoradi Thermal Plant, with an approximate length of 43 km and 124/132 km (a base case and an alternative are considered for the route to Takoradi) respectively.

2

ACRONYMS AND ABBREVETIONS A/G CPF FOC LTE FOC GPS KP MSL NDT IP P/L RoW SMYS U/G WGS84 FPSO PLET WD

3

Above Ground Central Processing Facility Fibre Optic Cable Land Terminal End Fibre Optic Cable Global Positioning System Kilometric Point Mean Sea Level, reference plane for elevations Not Destructive Test Intersection Point Pipeline Right of Way Specified Minimum Yield Strength Under Ground World Global System 1984 for co-ordinates reference Floating Production Storage Offloading Vessel Pipeline End Termination Water Depth

PROCESS AND UTILITY SYSTEM DESIGN DATA AND CRITERIA Refer to Jubilee Gas Export Pipeline Project Steady State Flow Assurance Study (Doc 00-ZA-E-08002 rev0) enclosed. Refer to Process study by Saipem Roma (Doc 00-ZAE-3000 rev0).


saipem


4

ROUTE SELECTION

5

Description Offshore Pipeline Route

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Date May 2010

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The Offshore Section of the Jubilee Gas Export System is constituted by a flexible riser that runs from the FPSO vessel to a PLET and then by a rigid pipeline to Bonyere. The pipeline overall length is 53.8 km. The system is designed to allow also the future tie-in of the export line relevant to a second FPSO. For this reason the export pipeline is divided in two section characterized by a different external diameter, respectively 12” and 16”. An In-Line SLED is installed at the end of the 12” section to allow the tie-in of the future line coming from the second FPSO. The 12” section is designed for the gas transportation of a single FPSO instead the 16” section is designed for the combined transportation of two FPSO. A further In-Line SLED may be installed along the 16” section to allow the tie-in of possible future developments. More details about offshore pipeline are depicted in the following paragraphs. The proposed route is enclosed in Section 7.1 of this report. In this document the bathymetric data of the area is shown, the pipeline section length and the seabed profile. 6

Description of Deep Water Section The deep water section of the export pipeline is characterized by an external diameter of 12.75-inch. The battery limits of this section are respectively:  the PLET that allow the connection with the rigid goose-neck of the riser;  the In-Line SLED where the subsea tie-in with the shallow water section is performed. The water depth range is comprises between 800m reached at PLET location to the 80 or 100m where the in-line SLED will be located. The length of the 12” section is:  15.0 km in case of diameter change performed at WD 80m;  18.0 km in case of diameter change performed at WD 100m. The seabed profile is characterized by a constant average slope of 5.2° from KP 0.0 to KP 6.0 and 0.72° from KP 6.0 to the tie-in location as shown enclosed in Section 7.1 of this report.

7

Description of Shallow Water Section The shallow water section of the export pipeline is characterized by an external diameter of 16-inch. The battery limits of this section are respectively:  the In-Line SLED;  the pipeline Land Terminal End (LTE) located near Bonyere. The water depth range is comprises between 80-100m reached at the tie-in location to the 0.0 m at the pipeline LTE. The length of the 16” section is:


saipem


 

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35.8 km in case of diameter change performed at WD 80m; 38.8 km in case of diameter change performed at WD 100m.

The seabed profile is characterized by a wide flat area from KP 18.0 to KP 33.0 where the average slope is 0.2°. A seabed depression is individuated from KP 33.0 to KP 48.0. This seabed feature seems to be not critical since the maximum slope is about 1.0°. From KP 48.0 to LTE the profile is quite flat. See enclosed in Section 7.1 of this report for details.


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Date May 2010

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Description of 18” pipeline route section from onshore plant to Takoradi plant From KP 0.00 TO KP 50.00 (refer to DWG n. 00-LB-A-81001) This pipeline route section that goes from Onshore Plant near Bunyere to Takoradi plant has been selected based on desk study on Ghana maps at scale 1:250000 scale and satellite pictures available on web. The pipeline route length is equal to 50. km. The main features of this on shore pipeline route is the position of itself in a pipeline corridor of existing pipelines that run from west to East along to cost in the dry land area with a clearance of 6 meter from existing ones (Refer to Typical pipelines RoW design, dwg n. 00-LC-D-81010). The pipeline route selection philosophy has been based on the arrangement of the new pipeline in parallel to the existing ones in the same pipeline corridor in manner to minimize and simplify the pipeline installation problems for which minor problems might also occur for the land acquisition. This on land pipeline section, even if a bit longer of the alternative one from onshore plant to Takoradi Plant of about 5 km, it has just 4 km of swamp/seasonal swamp while the rest of routing should be firm terrain. Typical soil of tropical areas should be the laterite soil, even if, further geotechnical investigation should be finalized to confirm the type of soil and for the evaluation of possible rock or outcrop rocks strata. The onshore pipeline ground profile can be considered almost flat with elevations ranging from 0.00 m to about 70.00 m above msl. The main pipeline features of this section can be summarized as follows: 1. 2. 3.

P/L length Dry land section Swamp section SMYS) 4. Gunite section

= =

50 km 48 km (18”/ wthk 7.9 mm DF 0.72 SMYS) = 2 km, (18”/ wthk 9.5 mm DF 0.6

=

5. Mainline Block Valve (MBV)

=

6. Parallelism section 7. Main roads crossings 8. Main creek/river xings

=

2 km, (5 cm of continuous concrete coating for the on bottom stability in swamp & river crossing sections) 1 @ KP 31 (1 every 20 miles as per Asme B31.8 para. 846) = 45 km (Clearance of 6.0 m) = 3 of National Road n. 312 4 (Eiule River, Bosoke Creek, Eia River, Ebi River) Location class 1

9. Location Class (Asme B31.8) =

Note: A detailed site recce survey along the pipeline route is highly recommended to finalise the pipeline route, the pipeline engineering and simplify construction problems. The environmental protected areas shall be investigated as well as the sacre groves that might be crossed along the pipeline route to avoid problems with Local Community and delay during construction. file: 310453835.doc This document is the property of Saipem SpA all rights reserved. Violators will be pursued under civil and criminal law.

saipem


Page 13 of 26

Date May 2010

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From KP 50.00 TO KP 132.50 (refer to DWG n. 00-LB-A-81002) This pipeline route section that goes from KP 50.00 to Takoradi Plant at KP 132.50 has been selected based on desk study on Ghana maps at scale 1:250000 scale and satellite pictures available on web. The pipeline route length of this section is equal to 82.50 km. The main features of this onshore pipeline route is the position of itself in the coast area of South of Ghana with main West–East direction. The pipeline route across the landscape with the presence of dense hydrographical system composed of primary and secondary rivers and creeks. Also in this pipeline section the routing has been located in a pipeline corridor of existing pipelines that run from west to East with a clearance of 6 meters. Therefore, the pipeline route selection philosophy has been based on the arrangement of the new pipeline in parallel to the existing ones, in the same pipeline corridor, in manner to minimize and simplify the pipeline installation problems for which minor problems might also occur for the land acquisition. Typical soil of tropical areas should be the laterite soil, even if, further geotechnical investigation should be finalized to confirm the type of soil and for the evaluation of possible rock or outcrop rocks strata. The onshore pipeline ground profile can be considered almost flat with elevations ranging from 0.00 m to about 70.00 m above msl. The main pipeline features of this section can be summarized as follows: 1. 2. 3. 4. 5. 6. 7. 8. 9.

P/L length = 82.5 km Dry land section = 80.5 km, (18”/ wthk 7.9mm DF 0.72 SMYS) Swamp section = 2 km, (18”/ wthk 9.5mm DF 0.6 SMYS) Gunite section = 2 km, (5 cm of continuous concrete coating for the on bottom stability in swamp & river crossing sections) Mainline Block Valve (MBV) = 3 @ KP 60, KP90, KP 120 (1 every 20 miles as per Asme B31.8 para. 846) Parallelism section = 80 km (Clearance of 6.0 m) Main roads crossings = 5 of National Road n. 312, 320, 300, 315 Main creek/river xings = 8 (Yiri River, Aukivao River, Nyan River, Bufre River, Hwini River, Aiyire River) Location Class (Asme B31.8) = Location class 1

Note: Also for this pipeline section a detailed site recce survey along the pipeline route is highly recommended to finalise the pipeline route, the pipeline engineering and simplify construction problems. The environmental protected areas shall be investigated as well as the sacre groves that might be crossed along the pipeline route to avoid problems with Local Community and delay during construction.


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Date May 2010

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00-LA-E-80000 Rev. 1

Alternative route From KP 0.00 TO KP 124.60 (refer to DWG n. 00-LB-A-81001) As shown in the enclosed project dwg n. 00-LB-A-81001, an alternative onshore pipeline route along the Gulf of Ghana coast to Takoradi Plant have been found. Even if this alternative route is shorter then the base case one to Tokoradi Plant (124.60 km Vs 132.50) in this section the length of swamp area reaches 16 km. The alternative route, from KP 0.00 to KP 50.00 section, runs sub-parallel to the coast with an offset of about 1-1.5 km. Problem with local community might be arisen since new pipeline corridor has been defined and it might create project impact in the land acquisition phase and in the construction time schedule and costs. The main pipeline installation equipments are concerning of installation suitable for swamp areas or creek and river crossings. The main pipeline features of this section can be summarized as follows: 1. P/L length 2. Dry land section 3. Swamp section 4. Gunite section

= = = =

5. Mainline Block Valve (MBV) = 6. Parallelism section 7. Main roads crossings 8. Main creek/river xings

= =

9. Location Class (Asme B31.8)=

124.60 km 108.60 km, (18”/ wthk 7.9mm DF 0.72 SMYS) 16 km, (18”/ wthk 9.5mm DF 0.6 SMYS) 16 km, (5 cm of continuous concrete coating for the on bottom stability in swamp & river crossing sections) 5 @ KP 31, KP 60, KP90, KP 120 (1 every 20 miles as per Asme B31.8 para. 846) = 25 km 5 of National Road n. 312, 320, 300, 315 10 (Amonsuri River, Yiri River, Aukivao River, Nyan River, Unnamed River, Bufre River, Hwini River, Aiyire River ) Location class 1

Note: A detailed site recce survey along the pipeline route is highly recommended to finalise the pipeline route, the pipeline engineering and simplify construction problems. The recce survey should be finalized for the understanding of status of swamp area if any along the coast if seasonal swamp or not in manner to finalize properly the engineering. The environmental protected areas shall be investigated as well as the sacre groves that might be crossed along the pipeline route to avoid problems with Local Community and delay during construction.


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Date May 2010

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00-LA-E-80000 Rev. 1

Description of 12” pipeline route section from onshore plant to Effasu From KP 0.00 TO KP 42.80 (refer to DWG n. 00-LB-A-81001) Also this pipeline section route section that goes from Onshore Plant near bunyere to arrival point near to Effasu has been selected based on desk study on Ghana maps at scale 1:250000 scale and satellite pictures available on web. The pipeline route length is equal to 42.8 km. The main feature of this pipeline route section is its position along the coast border that goes from East to West starting form Buyere to Effasu of Ghana state with the routing sub parallel to the coast. Most of the pipeline section is characterized from swamp or on land near shore areas, typical soil, along the pipeline route, should be laterite soil, for which a further soil investigation should be assessed for the evaluation of water table, seasonal swamp, and soil baring capacity. The ground profile can be considered almost flat with elevations ranging from 0.00 m to about 13.00 m above msl. The main pipeline features of this section can be summarized as follows: 10. P/L length 11. Dry land section 12. Swamp section 13. Gunite section

= = = =

14. Mainline Block Valve (MBV) = 15. Parallelism section 16. Main roads crossings 17. Main creek/river xings

= =

18. Location Class (Asme B31.8)=

42.80 km 22.80 km (12”/ wthk 5.6mm DF 0.72 SMYS) 20 km, (12”/ wthk 6.4mm DF 0.6 SMYS) 20 km, (2 cm of continuous concrete coating for the on bottom stability in swamp & river crossing sections) 23 @ KP 31 (1 every 20 miles as per Asme B31.8 para. 846) = 35 km 1 of National Road n. 312 4 (Eiule River, Bosoke Creek, Eia River, Ebi River) Location class 1

Note: A detailed site recce survey along the pipeline route is highly recommended to evaluate the status of swamp sections (length, and water density, etc) and the elevation of water table with impact in the project time schedule and costs.


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Date May 2010

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Description of 16” pipeline route section from LTE to onshore plant From LTE to proposed onshore plant near Bunyere (refer to dwg n. 00-LB-A-81014) As shown in the enclosed project dwg n. 00-LB-A-81014, an interconnecting 16” line that goes from LTE to the Onshore Plant location near Bunyere is foreseen with an approximate length of 1200 meter, where a major road is crossed. The LTE is defined has the point on the beach profile with the elevation 1 meter above the highest tide sea level with sealine ground intersection. The pipeline installation equipments for this near shore pipeline section are concerning to installation, for swamp areas or creek crossings as highlighted in the desk study by web images.

11

Proposed location for onshore plant closed to Bonyere As shown in the enclosed project dwg n. 00-LB-A-81014, the onshore plant near to Bunyere is proposed. The preliminary 700mx700m square area has been fixed considering the location suitable for on shore plant area. The selected area should have an easy access also for heavy vehicles since this one located near a main road that goes from Bonyere to Nauli and Effasu locations. A dedicate site recce survey should confirm the suitability of the proposed area as well as the soil property if adequate to the on shore plant installation equipments and loads.

12

Pipeline route findings The highlighted findings as follows:  Proposed 6 meter of pipeline clearance from existing pipelines in the parallelism section  All the pipeline routes should be further investigated by dedicate site survey to finalize and confirm the selected routes.  The “protected Local Communities Areas” should be defined along the pipelines routes to avoid problems with Local Community and delay during construction.  The swamp area in all pipeline sections should be assessed in manner to define construction time schedule & costs.  The soil properties should be carefully evaluated as well as the presence of rock or outcrop strata and their hardness to support the pipeline design and construction.

13

Onshore pipeline constructability The highlighted findings as follows:  

Pipeline installation equipments suitable for dry land section Pipeline installation equipments suitable in swamp sections. The type of swamp or seasonal swamp should be evaluated by a dedicate recce survey since this fact implies different installation equipments (small pontoons & cranes or swamp buggies)


JUBILEE GAS EXPORT

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Onshore plant & construction should be facilitated from an easy road network. However, the road conditions are unknown.

14

PROPOSED DESIGN CONFIGURATION

15

Offshore Gas Export Pipeline System Description As described in Sec. 4.1 the Offshore Section of the Jubilee Gas Export System is mainly constituted by:  a flexible Gas Export riser that runs from the FPSO vessel to a PLET located at about 800m WD;  a rigid flowline that runs with an external diameter of 12” from the PLET to an InLine SLED and then with a 16” external diameter to shore. The pipeline Wall Thickness selection and the pipeline On-Bottom Stability will be investigated in detail in dedicated technical reports. In this paragraph are reported a brief description of:  pipeline construction methodologies;  shore approach design;  pipeline third party interaction and protection requirement;  subsea structures (PLET and In-Line Sled). Description of Proposed Construction Methodologies The construction process of the offshore pipeline is determined by the simultaneous presence of a deep water section and a shallow water one. This leads to the use of a construction vessel able to perform both S-Lay and J–Lay or to the use of two different vessels. Based on a preliminary analysis the offshore pipeline construction process can be summarized as follow: a pull-in will be performed from shore and then the pipeline laying will start with the SLay method till a Water Depth of about 200m where the pipeline will be abandoned; After performing the pipeline recovery, the lay process will continue in J-Lay method till PLET abandonment. For both scenarios the necessity of an above water tie-in will be evaluated in a more detailed analysis based on vessel characteristic and seabed morphology of the shore approach. The necessity of an above water tie-in will be evaluated in a more detailed analysis based on vessel characteristic and seabed morphology of the shore approach. The gas export flexible line will be laid from the FPSO to the PLET subsea. The FPSO operator will deploy a messanger line through the FPSO I-tube. Construction vessel, set at adequate distance, will recover the messanger line onboard the vessel, attach it to the riser pulling head and start the deployment. FPSO operator will pay-in on the messanger line while riser is paid-out from construction vessel in steps, maintaining the desired U-shape of the catenary. At the end of the pull-in, once pulling head is secured at HOC on the FPSO, construction vessel will continue laying. Buoys will be attached to create the desired lazy wave shape and the gooseneck c/w RT will be connected on the 2nd end for PLET connection.


JUBILEE GAS EXPORT

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An alternative solution for the connection of the FPSO with the PLET will be proposed, in a dedicated document, with the aim of reducing the flexible riser length in order to minimize the overall project cost.


JUBILEE GAS EXPORT

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Date May 2010

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Description of Shore Approach The shore approach will be characterized by a dredge section till a WD of about 15m from where the pipeline post-trenching will be performed. For the pipeline section comprises in the WD range 0 – 30m a pipe specific gravity in empty condition of 1.4 will be guaranteed in order to avoid any risk of pipe outcrop. For WD deeper than 30m a specific gravity value of 1.2 is considered appropriate. Pipeline third party interaction and protection requirement The pipeline route develops in an area with an extensive fishing activity. For this reason the post-trenching of the entire 16” section is recommended. The requirement of post trench should be extended also to a section of the 12” pipeline. The extension of the post trenching section for the 12” pipeline will be defined after more detailed analysis. Subsea Structure Description Two tipe of subsea structure are required in the Offshore Gas Export Pipeline. A PLET is required for the connection of the export riser to the pipeline. The PLET has to be equipped with a connector hub able to perform the connection with the rigid gooseneck of the riser. The wide water depth in which the PLET is located (800 m) allows the use of a Vertical Connection System. Based on preliminary risk assessment study the PLET will be equipped with a choke and a ball valve. Here below is reported a photo that shows a PLET used in a deepwater project performed by Saipem.

An In-Line SLED is required at the end of the 12” section to allow the tie-in of the future line coming from the second FPSO. In this area the WD is 80 or 100m then this structure has to be designed taking into account the possible interaction with the fishing activity. Then the In-Line SLED will be equipped with a horizontal connection system (flange) and protected with an over-trawable structure or mattresses. Here below is reported a figure that shows the piping of a typical In-Line SLED.


JUBILEE GAS EXPORT

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A further In-Line SLED may be installed along the 16” section to allow the tie-in of possible future developments.


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Page 21 of 26

Date May 2010

JOB: 045942

00-LA-E-80000 Rev. 1

On shore pipeline Design Configuration Unless differently stated the onshore pipeline design shall be in compliance with ASME B31.8 latest edition and good pipeline engineering practice. Herein the proposed design configuration: i.e.:  

Pipeline piping rating will 600#



RoW design as detailed in enclosed typical dgw 00-LC-D-81010



Pipe cover will be 1 meter in firm terrain, 0.6 meter in swamp area, and 1.5 meter. in the road crossings.



MBVS will have just welded piping no flanges



The main roads crossings will be done by casing pipe with open cup method



The Anchor block design will be based on stress analysis results





17

Line pipe will be API 5L-X65, DF= 0.72 (line), 0.6 (swamp) & 0.5 (xings) of SMYS

On bottom stability by continuous concrete coating based output results of swamp areas report and geotechnical investigation results. (water specific density assumed equal to 10.25 kN/m3, concrete coating density equal to 23.54 kN/m3 , Continuous concrete coating specific gravity value = 1.15 All mainline block valves shall be equipped with solar panels for energy supply.



The pipelines system shall have the local corrosion monitoring system with data logger type microcor or equivalent



The pipelines system will be isolated by isolating joint at start and end point of each line unless define differently form the client



The pipelines system will be protected by cathodic protection system by impressed current system.



Ground bed will be placed near to the onshore plant area or wherever it will be established during the detail design based on resistivity survey results.



External coating by 3 layers PE coating



Internal liner not required



The pipelines system shall be equipped with FOC

Pipeline design codes American Society of Mechanical Engineers (ASME) ASME B 31.8 ASME B 30.14 ASME ASME B 16.34

Gas transmission and distribution piping system Side Boom Tractors Boiler and Pressure Vessel Code Section VIII, Division 1, Rules for Construction of Pressure Vessels Section IX, Welding and Brazing Qualification Requirements Valves-Flanged, Threaded and Welding Ends


JUBILEE GAS EXPORT

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ASME B 16.5 ASME B 16.9

Page 22 of 26

Date May 2010

JOB: 045942

00-LA-E-80000 Rev. 1

Pipe Flanges and Flanged Fittings/ Factory-Made Wrought Steel Butt Welding Fittings

American Petroleum Institute (API) API Spec 5L API RP 1102 API Std 1104 API RP 1110 API Spec 6D API Spec 6FA API Std 598

Specification for Line Pipe Recommended Practice for Liquid Petroleum Pipelines Crossing Railroads and Highways Standard for Welding Pipelines and Related Facilities Recommended Practice for the Pressure Testing of Liquid Petroleum Pipelines Specification for Pipeline Valves (Gate, Plug, Ball and Check Valves) Specification for Fire Test for Valves Tanks and Piping Systems Valves Inspection and Test

American Society for Testing and Materials (ASTM) ASTM A 36 ASTM A 105 ASTM A 350 ASTM A 370 ASTM A 515 ASTM A 707 ASTM E 125 ASTM E 747 ASTM G 14 ASTM G 39

Standard Specification for Structural Steel Standard Specification for Forgings, Carbon Steel, for Piping Components Standard Specification for Forgings, Carbon and Low-Alloy Steel, Requiring Notch Toughness Testing for Piping Components Standard Specification for Mechanical Testing of Steel Products Standard Specification for Pressure Vessel Plates, Carbon Steel, for Intermediate -and Higher-Temperature Service Standard Specification for Flanges, Forged, Carbon and Alloy Steel for Low-Temperature Service Standard Reference Photographs for Magnetic Particle Indications on Ferrous Castings Controlling Quality of Radiographic Testing Using Wire Penetrometers Standard Test Method for Impact Resistance of Pipeline Coatings (Falling Weight Test) Standard Practice for Preparation and Use of Bent-Beam Stress Corrosion Test Specimens

Manufacturers Standardization Society (MSS) MSS SP-6 MSS SP-25 MSS SP-53 MSS SP-54 MSS SP-55 MSS SP-75 MSS SP-93

Standard Finishes for Contact Faces of Pipe Flanges and Connecting-End Flanges of Valves and Fittings Standard Marking System for Valves, Fittings, Flanges and Unions Magnetic Particle Examination Radiographic Examination Quality Standards for Steel Castings for Valves, Flanges and Other Piping Components (Visual Method) Specification for High Test Wrought Butt Welding Fittings Liquid Penetrant Examination


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MSS SP-94

Page 23 of 26

Date May 2010

JOB: 045942

00-LA-E-80000 Rev. 1

Ultrasonic Examination

American Welding Society (AWS) AWS QC1 AWS D1.1

Standard and Guide for Qualification and Certification of Welding Inspectors Structural Welding Code

Pipe Fabrication Institute (PFI) PFI ES3

Fabricating Tolerances

National Association of Corrosion Engineers (NACE) NACE MR 0169 NACE MR 0175 NACE RP 0177 NACE RP 0274 NACE TM 0284 NACE RP 0286 NACE RP 0287 NACE RP 0490 NACE RP 0572

Control of External Corrosion on Underground or Submerged Metallic Piping Systems Sulfide Stress Cracking Resistant Metallic Materials for Oil Field Equipment Metallic Structures and Corrosion Control Systems High-Voltage Electrical Inspection of Pipeline Coatings Prior to Installation Evaluation of Pipeline Steels for Resistance to Stepwise Cracking The Electrical Isolation of Cathodically Protected Pipelines Field Measurement of Surface Profile of Abrasive Blast Cleaned Steel Surfaces Using a Replica Tape Holiday Detection of Fusion - Bonded Epoxy External Pipeline Coatings of 10 to 30 Mills (0.25 to 0.76 mm) Design, Installation, Operation and Maintenance of Impressed Deep Current Ground Beds

Institute of Petroleum (IP) Electrical Safety Code, Part 1 and Part 15 International Electro technical Commission (IEC) No. 19200.72.63.001

Onshore Pipeline Cathodic Protection

International Organization for Standardization (ISO) ISO 9000 to 9004

Quality Systems

DIN 30670

Polyethylene coatings of steel pipes and fittings; requirements and testing.


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Page 24 of 26

Date May 2010

JOB: 045942

00-LA-E-80000 Rev. 1

18

EXECUTION SCHEDULE

19

Onshore pipeline detail design work schedule (site survey, eng, proc, const) Herein the on shore pipelines work schedule of level 1.


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Page 25 of 26

Date May 2010

JOB: 045942

00-LA-E-80000 Rev. 1

1

ON SHORE PLANT SCHEDULE (HOLD)


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Page 26 of 26

Date May 2010

JOB: 045942

00-LA-E-80000 Rev. 1

ATTTACHMENTS 21

Steady State Flow Assurance Study

(00-ZA-E-08002)

22

On shore Plant Process Report

(00-ZA-E-3000)

23

Off-shore Gas export pipelines route map

24


25


26

12” Pipeline route map from onshore plant to Effasu from KP 0.00 to kp 42.80 (00-LC-D-81003)

27

Map of proposed location for onshore plant near Bunyere (00-LC-D81014)

28

Typical pipelines ROW Design

(00-LC-D-81010)

29

Typical ditch dimension

(00-LC-D-81011)

30

Typical main line block valve scheme

(00-LC-D-81012)

31

Launcher/Receiver typical layout

(00-LC-D-81013)

32

Metering station typical layout


Ghanas Jubilee Gas Export Pipeline Project

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