Subsea Pipeline Inspection

GUJARAT STATE PETROLEUM CORPORATION LIMITED

Doc. No. : GSPC/SubPPL/IP&CL/01 Rev. No. : 00 Issued : 12-03-2015

Title : Procedure cum Check List for Inspection of Subsea Pipeline

PROCEDURE CUM CHECK LIST

FOR

INSPECTION OF SUBSEA PIPELINES

Approved By : Verified By : Reviewed By : Prepared By :

Mr. N.K. Mitra (C.O.O) Mr. Ravi T Job (SVP-Offshore Operations) & Mr. Nag Mani (VP-IMR) Mr. Shashikant Singh (Manager-Pipeline) & M/s ABS Mr. Praveen Kumar Choudhary (Officer-E&P)

Doc. No. : GSPC/SubPPL/IP&CL/01 Rev. No. : 00 Issued

: 12-03-2015

SCOPE OF WORK FOR INSPECTION Subsea Pipeline

Table of Contents 1.0 Introduction ................................................................................................................................ 2 1.1 Scope ....................................................................................................................................... 2 1.2 Reference Documents .............................................................................................................. 2 1.3 Abbreviations……………………………………………………………………………………………………………………………2 2.0 Technical Description .................................................................................................................. 3 2.1 DDW-Field ............................................................................................................................... 3 3.0 Inspection Scopes ....................................................................................................................... 3 3.1 Inspection Procedures ............................................................................................................ 4 3.1.1 Process of General Visual Inspection ............................................................................ 5 a). In High seas up to approximately 15 Meters of Draft..................................................5 b). Shallow Water Inspection (Draft Less than 15 meters) …………………………………………...6 c). Near Shore Survey…………………………………………………………………………………………………...6 d). Task Matrix……………………………………..…………………………………………………………………….…7 4.0 Pipelines ..................................................................................................................................... 7 4.1 Recording and Measurement for General Visual Inspection .................................................... 7 4.2 Engineering Analysis Tasks…………………..………………………………………………………………………………….8 A. Pipeline Field Procedures ............................................................................................................ .9 A.1 Pipeline general Visual Inspection………………………………………………..…………………………………….….9

1


1.0 Introduction This document is prepared to identify the scope of activities for inspection of subsea pipeline to enable capturing of data for Risk Based Assessment of system along with Engineering criticality assessments (ECA) , as per requirement. This Inspection activity is to ensure GSPC to Operate and manage their assets continuously with the highest levels of integrity and safety. Optical fibre cable is piggy back. One umbilical is also laid alongside from PLQP to SSIV.

1.1 Scope This document is applicable to the Deen Dayal Field (Block KGOSN/2001/03) situated offshore from the Yanam – Kakinada coast of Andhra Pradesh, India This document is concerned with the subsea Pipelines.

1.2 Reference Documents Document Number

Title DRAWINGS

D-3-POIN.02-001-140-Rev-02 D-3-POIN.02-001-180-Rev-A D-3-POIN.02-001-175-Rev-A

Alignment sheet for 20 Ǿ Submarine pipeline from KP0.0 to 2.5 sheet from 1 to 8 Lateral General Arrangement SSIV General Arrangement

PROCEDURES OISD-STD-139 OISD-STD-188 GSPC/AIMS/UW/IRR-01

Inspection of pipelines -Offshore Corrosion Monitoring of Offshore and Onshore pipeline Integrity Management Manual & Inspection Reporting Requirements Underwater Installations

1.3 Abbreviations Abbreviations

Description

CP

Corrosion Protection

DGPS DP m mm MSL PTW ROV SSIV WT

Differential Global Positioning System Dynamic Positioning Meters Millimetres Mean Sea Level Permit To Work Remotely Operated Vehicle Sub Sea Isolation Valve Wall Thickness

2


2.0 Technical Description 2.1 DDW-Field The Company has discovered a significant reserve of gas in the western part of the Contract Area and discovery has been named as Deen Dayal West (DDW) with the KG#8 discovery well located 15 KM offshore in 60 meters of water depth. The reservoir is characterized by high temperature and high pressure. Surface facilities for Deen Dayal West Development have four components (i) Wellhead Platform (WHP), (ii) Process cum Living Quarters Platform (PLQP) (iii) Multiphase subsea pipeline to OGT with slug catcher and (iv) Onshore Gas Terminal (OGT).

  





Subsea Pipeline network consists of following associated facilities: 20” Multi Phase Pipeline of approx. 24.5 Km length (21.5 Km submarine section and 3 Km Onshore section) from PLQP to OGT. 10” Effluent Disposal Pipeline of approx. 15 Km length (12 km submarine section and 3 Km Onshore section) from Effluent Treatment Plant in OGT to disposal point in sea. Associated above ground facilities at Isolation Valve Station (IVS) and OGT namely Slug Catcher, Pig Receiver, Close Blow Down Drum, Valves etc including associated Electrical and Instrumentation works for 20” multiphase pipeline. Optical Fiber Cabling of approx. 24.5 Km length (21.5 km submarine section and 3 Km Onshore section) from PLQP to OGT Control Room etc including associated Electrical and Instrumentation works. Laying of approx. 3 km of Power cable from OGT to IVS. Sub Surface Isolation Valve (SSIV), Station Isolation Valve (SIV) and Umbilical for 20” multiphase pipeline at (a) above.

3.0 Inspection Scopes This Inspection scope provides detail of Inspection, maintenance and monitoring activities required to Identify, locate and /or mitigate any threat to the system / asset. In-service Inspection during steady state operation after base line survey becomes an important tool for assessment and prioritisation of Inspection & maintenance activities by Risk Based Assessment / Inspection. General Visual Inspections (GVIs) during steady state operation will provide information / highlight any threats / damage to the production assets visual externally. Examination and analysis will lead to proper action for mitigation or to leave with the same in case it emerges that, it will not affect the operation in time to come. Special inspection would be required, in case of any significant environmental event or when third party damage is reported, to confirm location and orientation of the assets and to record any damage or debris. Possibility of integrating any other relevant job with special inspection will be explored at that point of time. This will help in optimising the cost. 3


3.1 Inspection Procedures Inspection procedure will capture all the requirement, which is required to perform the activity satisfactorily, in terms of Equipment, tools, measuring Instrument, Vessel and personnel. The procedure will also detail method of capturing the information. Inspector shall have appropriate 3.4 U certification. A detailed technical description of the event is also captured along with any related or linked events. Inspection events can be scheduled as tasks and would be considered work orders that could be entered into a Maintenance Management system.

      

Inspection of export trunk pipelines will involve the following activities to either confirm the adequacy or condition/status of items mentioned below: Adequacy of the CP system; Damage or deformation to the lines; Areas of free-spanning or buckling or determine the extent; Monitoring stabilization including rock protection berms; Debris around pipeline; Marine growth measurements ,if any; and, Internal pig inspection. The inspection of pipelines requires traversing the total route of subsea pipeline either by flying the ROV or Diver, and so it is different from that of static or Rotary equipment, the ROV should have boom arms fitted with lights and cameras for total coverage in single trip, as pipeline is of 20”diameters. In case the same ROV system is required for carrying out baseline survey then two runs will be required: 1. To plot the position of the pipeline 2. To record any events or anomalies. Done by other group. Internal pig inspections will be conducted to establish baseline wall thickness and defects measurements for trending and future risk based inspection scheduling. Then, optionally, will be repeated after 5 years, on basis of assessment of result of maintenance pigging analysis along with Iron count & SRB. A side-scan sonar inspection of the shallow water section of the export trunk lines and Effluent line will be required in order to establish any exposures. Pipelines End Terminations are treated as integral sub-components of the pipelines. Risers will be treated and inspected with Platform jacket inspection, as the requirement will differ. More over this forms part of structure section than pipeline. Risers and appurtenances will be inspected as part of the PLQP jacket inspection. 4


3.1.1 Process of General Visual Inspection a)

In High seas up to approximately 15 Meters of Draft MSV with suitable diver or ROV and Dynamic Positioning 2 capability to perform inspection on the Pipelines for pipeline section in sea will be mobilised along with suitable diver / ROV compliment. In the river section big boats like MSV will not be very helpful. Small boat with survey with Sonar facility will be required for this section.

1. 2.

3. 4. 5.

6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.

The Inspection shall be started after proper location of Diver/ ROV Start pipeline inspection from the end facing the structure (PLQP) to which the first end is connected. Connector or flange to be inspected for indications of damage or other anomaly. Alignment of the flange to be confirmed and bolts (In case of Bolted flanges) are in place and note the presence of any grease bands or flange protectors. Take CP readings on either sides of the flange. Diver/ROV to fly out along the length of the pipeline with the camera centred on the pipeline and vessel DP in “Follow Target” mode, centred on the Diver/ROV beacon. Adjust ROVs both port and starboard boom arms to a height to enable viewing of both sides of the pipeline on the displays. NOTE: Maximum coverage of inspection of pipeline shall be better for QA purpose during visual Recording , so “ Flying Vee “ formation of Camera with Optimal set up of Boom camera and central Camera will be required.. Or Diver will have to adjust the camera to take photo of both sides of pipeline in same fashion. In case of completely buried pipeline, pipeline tracker to be deployed for confirming the pipeline status. Inspect and indentify any features or anomalies associated with Wet Coating Damage on pipeline. Note position, length, etc. Locate free span and note position, length, gap and soil condition. Note: Free Span Survey shall be carried out annually as per OISD-STD-139. Condition, security and wastage of bracelet anodes. CP reading and CP profiling. Note: Anodes shall be inspected once in three years as per OISD-STD-139. Any buckles or evidence of trenching which would indicate relative movement are to be noted. Inspect the pipeline in buried section under rock dump or berm, Identify exposed section, if any, and length of the exposure, thereof. In case of suspicion regarding Coating damage, Coating Damage survey will be done by suitable method like DC VG etc. Take position fixes at any turns, features or snake-lay sections and at every 500m. Fix the start and end of any stabilised section, noting the type of stabilization. Sonar survey with ROV / Diver to be conducted for proper identification of Debris out of visual range of the camera, if any, within 15m either side of the pipeline. Follow the pipeline upto the second end of the connector. Repeat step 2 at other end also. 5


b)

Shallow Water Inspection (Draft Less than 15 meters) Barge / small boat will be mobilised with suitable deployed Side scan Sonar (SSS), preferably deployed on a pole to perform the SSS inspection on the shallow water sections including river section (Draft less than approximately 15 meters) of the pipelines. Feasibility of using Multi Beal Swath Bathymetry can also be evaluated at the time of survey for better result. Multiple runs of the pipeline route may be required to cover the entire width of the estuarine section where the water is very shallow on account of properties and design of SSS profilers. The following steps to be followed: 1. 2. 3. 4. 5.

c)

Mobilize the barge / small boat. Deploy, setup, calibrate and test the survey equipment. Start survey from the shallowest section possible Record and plot the SSS swath using the survey equipment. . Follow the route of the pipeline to complete survey of this section of the pipeline route. Terminate the inspection when in 15m of water or till measurement /Inspection is possible in estuarine section.

Near Shore Survey A shallow draft vessel with draft of less than 1.5 meters with sufficient space for 4 additional personnel apart from Marine crew will be required for this section. Inspection of this portion will be done with a reduced spread of inspection equipment to determine the level of cover of the pipelines in the estuarine region. The vessel should have sufficient office space to setup equipment and record the results of the survey. The primary survey spread will be side scan sonar or preferably multi-beam swath bathymetry. The main advantage of multi beam swath bathymetry, like Kongsberg GeoSwath plus System, is the accuracy of mapping, the ease of deployment (pole mounted sensor heads) and high speed mapping of features.

d)

Task Matrix Minimum Activities required to complete this inspection are listed below, in place of an exhaustive workscope. SSS

Exposure

Damage

Scour

Free Span

Debris

Burial

Fix

Coating

Anode

CP

GVI

Component

6


Pipeline (On Bottom) Pipeline (Rock Dumped) Pipeline (Shallow Water) Stabilization

X

X

X

X

X

X

X X X

X

X

X

X

X X X X

X X X

X X

4.0 Pipelines 4.1 Recording and Measurement for General Visual Inspection The following needs to be recorded:        

Burials of the pipeline in sand seabed sections with any exception. Any exposures of the pipeline in rock protection berms. Free spans of the pipeline. Apparent lateral movement of the pipeline as evidenced by trenching and/or self burial. Signs of damage or deformation. Weightcoat or coating damage. Location and size of any debris present on or in the vicinity of the pipeline, if any. Check CP system on the pipeline with appropriate CP equipment. Only any exposed steelwork and/or anodes at regular intervals should be considered as reference stabs. As per requirement either stab or CP profiling will be done. The following events are important component: Anode /CP Condition  Berm  Bolted item  Burial  Coating Condition / damage

 Damage  Free Span  Leak Observations  Scour  Stabilization

 Crossing The deliverables expected from inspection on this type of asset include: 1. Report of all events recorded, all anomalies observed and all measurements required at the recorded KP from the baseline surveyed line-file. 2. Executive summary of the recorded events and anomalies. 3. Digital Video Media Files of the Inspection.

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4.2 Data Evaluation & Assessment of Fitness  Remaining Anode Life Calculations based on trended CP and anode wastage readings.  MAOP (Maximum Allowable Operating pressure) assessment based on remaining wall thickness measurements from UT and internal pigging inspections.  Pipeline buckling and bending resistance.  On-bottom stability, VIV investigation and interacting span analysis.

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A. Pipeline Field Procedures A.1 Pipeline General Visual Inspection WORK INSTRUCTION SHEET Job Title:

Pipeline General Visual Inspection

Pipeline ID

Date of Survey

PTW No. Reference Document Number

Title

Reference Documents

History:

The primary function of the pipeline is to convey the gas from the PLQP/WHP to Onshore Gas Terminal (OGT).

Aim:

General Visual Inspection (GVI) is carried out to identify and locate any damage or upset conditions which may have occurred in the system during service period with potential to affect the production and protective systems. After GVI, different methodology can be deployed for further ascertaining the Integrity of pipeline system. Inspection / survey will be carried out as per methods described elsewhere in document in different water section.

Duration:

Task Duration will be dependent on pipeline length.

Materials:

Work Class ROV  7 Function Manipulators and 5 function Grabber  Colour Centre Camera on Pan & Tilt Module  Sonar (Tritech or Equiv)  Port & Starboard Boom Arms fitted with Cameras & Lights HIPAP Survey Spread with Beacons interfacing with Vessel (or Independent) DGPS Dual cell CP Probe with Remote Cell and CP Recording Software (Isis CPDAS or Equiv) Dual Head scanning Sonar for (Pipe line Survey) with Profiler and Recording Software – (Tritech SCU3 or Equiv) Pipeline tracking system (TSS 440 or equivalent) Recording reading Software 3K PSI Water Blaster Ultrasonic Wall Thickness Meter ( Cygnus for ROV and Diver) Contact CP System 9


Field CP Gradient system with qualified qualified Inspector having minimum 500 hrs of Inspection experience. Coating Damage Inspection equipment ( DCVG or equiv) [Optional] Rotary Hydraulic Brushes (or Equiv) [Optional] ROV Work Blast Or Equivalent Diver spread

GVI of Risers Damage Survey Anode Activity & Wastage CP Readings on Steelwork Field Gradient Debris Survey Burial Survey Freespan Survey Structural orientation and scour survey Corrosion Spool inspection (Where applicable) Coating Damage Hydrate Survey Scour Survey Inspection for Leaks

Tasks:

Work Permit: Step 1.

2.

1 Survey Included with GVI Readings at set interval on the pipeline and on sub-components. Readings on sub-components plus at exposed steel Continuous Reading during survey 5m either side of the pipeline Included with GVI Included with GVI Included with GVI Included with GVI Included with GVI Included with GVI Included with GVI Included with GVI

PTW required in accordance with Subsea Pipeline requirement

Discipline Diving Spread /ROV Diver (Inspectors) /ROV

3.

Diver (Inspectors) /ROV

4.


Description of Activity Start by positioning Diver/ ROV close to the structure.

Initial

Capture identity of Pipeline and position the Diver/ROV on the start point of the pipeline near PLQP. Also capture the tie back Optical Fibre and follow throughout the pipeline. Diver/ROV to fly out along the length of the pipeline with the camera centred on the pipeline Adjust ROVs both port and starboard boom arms to a height to enable viewing of both sides of the pipeline on the displays. As per 3.1.1 a. 5 above Inspection to Identify the following features but not limited to:  Anodes  Coating  Deformation/ buckling  Field joints (every 10th) 10


Step

Discipline      

5.

6.

7.

Diver (Inspectors) /ROV Diver (Inspectors) /ROV


Description of Activity Repair works Corrosion monitoring spools In-line Tees Crossing Stabilization features Span supports

Initial

Follow 3.1.1 a. 13

Anodes: Accessible anodes to be visually inspected and record the following :  Location  Secure (Y/N)  Active (Y/N)  Wastage (%) Note: Anodes shall be inspected once in three years as per OISD-STD-139. Berms: Visually inspect berms and record the following :  Start [KP]  End [KP]  Height [m]  Supporting [Y/N]  Supported length  Exposures The dual head profiler shall be used to profile the berms.

8.


9.


11.


Burial: Visually inspect f pipeline burial and record the following:  Start [KP]  End [KP]  Depth [m]  Length [m]  Burial Percentage [%] The dual head profiler shall be used to profile the seabed condition. Coating Damage: Inspect the Coatings on the pipeline and note the presence of any damage, delamination, abrasion, bubbles or other upset condition. Record  Damage (Y/N)  Type [Blisters, Bubbles, Bare Metal, Impact, Coating Defect]  Extent (%) CP Monitoring: The field gradient is to be recorded continuously along the full length of the Pipeline and around all features. 11


Step

Discipline

Description of Activity Take cathodic potential readings as follows: - on each anode field joint welds. - on all areas of exposed bare metal. - on either side of any mechanical pipe joints. - at the back of all uncoated tubeturns.

Initial

CP contact readings shall be taken at areas of exposed steel

12.


13.


14.


15.


During the survey, intermittent CP contact stabs on anodes will be performed, as required, for more precise readings. Typically, readings will be taken at every anode within 500m from structure, then every 1km within 20km of a structure for exposed pipeline. If the pipeline is buried then the Divers/ ROV shall continue with the inspection and take a CP Anode stab at the next possible location as convenient and possible. Crossings: Visually inspect any crossing and record the following:  KP Location  Line crossing [Name]  Separation Distance [mm]  Supported [Y/N] The dual head profiler shall be used to profile the crossing. Damage: Inspect the pipeline and record the event criteria. For damages found and record the following.  KP Location  Damage Type  Extent (Length x Breadth)  Leakage (if applicable)  CP stab of bare metal/damage (where applicable) Debris: Follow 3.1.1 a. 14 and record the following  KP Location  Type of Debris  Contact [Y/N]  Distance form Component [m]  Damage Type  Size Note: A sonar shall be used on the RO such that items of debris can be identified out of visual range of the camera. Debris cleaning should be done once in six months as per OISD-STD-139. Freespans: Identify freespans and Record the following :  Start [KP] for each touchdown point  End [KP] for each touchdown point  Length (M) for each touchdown point  Start Seabed Type [Silt, Sand, Clay, Coral, Rock] 12


Step

Discipline  

Description of Activity End Seabed Type [Silt, Sand, Clay, Coral, Rock] Touchdown Point [Sub-Event]

Initial

The dual head profiler shall be used to profile the pipeline relative to the seabed. Note: Free Span Survey shall be carried out annually as per

16.


17.


18.


19.


20.

21.



OISD-STD-139. Leaks & Hydrates: Visually inspect the accessible pipelines for Leaks  Location  Estimate of the Leak Rate  Hydrate Formation [Y/N] Note: Leak Detection System shall be calibrated for accuracy and effectiveness of operation before every operation Marine Growth: Identify and record the presence of marine growth.  Type (Hard/Soft)  Coverage  Height (mm) Scour: Visually Inspect for scour. Record the following:  Scour Present (Y/N)  Depth (mm) The dual head profiler shall be used to profile the scour. Stabilization: Visually inspect the stabilization. Orbit the entire emplacement with ROV / Diver, check scouring at the base of the support. Record the following:  Start [KP]  End [KP]  Type  Supporting [Y/N] The dual head profiler shall be used to profile the pipeline relative to the seabed. Trenching: visually inspected rock berms and record the following :  Start [KP]  End [KP]  Backfill Start [KP]  Backfill End [KP] The dual head profiler shall be used to profile the trench. Corrosion Monitor (If present): Inspect for corrosion, general condition and damage. Perform CP readings on the corrosion monitor frame at locations provided at the time of inspection. Perform CP 13


Step 22.

23.

24.

Discipline Diver (Inspectors) /ROV

Description of Activity readings on one anode. Anchor Bracelets (If present): Inspect pipeline anchor bracelets and record the condition, damage, anode usage and security of anchor connection.


Perform CP reading on the anchor bracelet frame at locations provided at the time of inspection. Perform CP readings on one anode. Anchor Box (If present): Inspect pipeline anchor box and record condition, damage, anode usage and condition of interface with the anchor bracelet.


Take CP Readings on the pipeline anchor at locations provided at the time of inspection. In-Line Tee or Lateral: Inspect In-line Tee or Lateral and record condition, damage, coating condition, anode usage, valve condition, mud mat condition and leaks.

Initial

Take CP Readings on the In-line Tee or Lateral on appropriate locations as provided at the time of inspection. 25.

26.

27.

Diver (Inspectors) /ROV Diver (Inspectors) /ROV Diver (Inspectors) /ROV

Confirm Diver /ROV Interface are clear of debris, marine growth and damage Confirm Identification markers are present and visible.

Flanges & Connectors: Inspect the connector or flange for indications of damage or other anomalies. Confirm the alignment of the flange, that all bolts are in place and note the presence of any grease bands or flange protectors. Take CP readings on either side of the flange

28.


Recover the DIVER/ROV.

Reporting: The following shall be handed over on completion of the inspection: 1. Visual Media file containing: a. Video Capture of all inspection activities b. Processed Survey and inspection files c. Event Logs using the approved event format. 2. Field Report Detailing: a. Summary of inspection and survey results b. Job work Break Down i. Operational Summary 14


ii. Standby and Operational time break with brief iii. Risk assessment Report iv. Threat perception of Survey team v. Constraint’s faced during Survey vi. Safety Events vii. Incidents viii. Permit to Work c. Summary of the vessel activities and durations d. Daily Progress Reports e. Calibration Details 3. Updated field Layout drawing in a native file format and pdf format.

COMPLETION: Inspectors Name Client Name

Signature

Date

Signature

Date

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Subsea Pipeline Inspection

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