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PHEONWJ-W-PRC-0011~0 (Guidance on Offshore Pipeline Installation)
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Transcript of PHEONWJ-W-PRC-0011~0 (Guidance on Offshore Pipeline Installation)
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PT. PHE ONWJ Guidance on Offshore Pipeline Installation
PHEONWJ-W-PRC-0011 Rev.0 Page 2 of 27
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Revision Log Register
Revisions had been performed on following pages:
Page Date Revision
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Table of Content
Revision Log Register ........................................................................................................................... 2
Table of Content .................................................................................................................................... 3
1. Scope ............................................................................................................................................. 5
2. References .................................................................................................................................... 5
2.1 Local Regulation and Standards ............................................................................................. 5
2.2 Company Specification ........................................................................................................... 5
2.3 International Standards and Codes ........................................................................................ 6
3. Definition of Terms ......................................................................................................................... 6
4. Abbreviations ................................................................................................................................. 6
5. Health, Safety and Environment .................................................................................................... 6
6. Competence Assurance ................................................................................................................ 6
7. Operational Organization ............................................................................................................... 6
8. Design Data ................................................................................................................................... 7
9. Installation Equipment ................................................................................................................... 7
10. Construction Engineering and Procedures .................................................................................... 7
10.1 Engineering ......................................................................................................................... 7
10.2 Procedures .......................................................................................................................... 9
11. Pre-lay Survey ............................................................................................................................. 10
11.1 General .............................................................................................................................. 10
11.2 Scope Considerations ....................................................................................................... 10
12. Pipe Lay ....................................................................................................................................... 10
12.1 Transportation ................................................................................................................... 10
12.2 Alignment .......................................................................................................................... 10
12.3 Shallow Water Pipelines.................................................................................................... 11
12.4 Lay Operations .................................................................................................................. 11
12.5 Pipelay Equipment Check ................................................................................................. 11
12.6 Tension Control ................................................................................................................. 12
12.7 Monitoring and Control of Pipe Configuration ................................................................... 12
12.8 Strip Chart Records ........................................................................................................... 13
12.9 Abandonment and Recovery of Pipeline ........................................................................... 13
12.10 Wet and Dry Buckle Repair ........................................................................................... 14
12.11 Diving ............................................................................................................................. 14
12.12 Pipeline Initiation and Termination ................................................................................ 14
12.13 Pipe Laying Records ...................................................................................................... 15
13. Crossing ....................................................................................................................................... 15
14. Welding ........................................................................................................................................ 15
14.1 General .............................................................................................................................. 15
14.2 Equipment ......................................................................................................................... 15
14.3 Welding Consumables ...................................................................................................... 16
14.4 Welding Procedure Specification (WPS) ........................................................................... 16
14.5 Welding Procedure Qualification (WPQ) ........................................................................... 16
14.6 Qualification of Welders .................................................................................................... 16
14.7 Production Welding ........................................................................................................... 16
14.8 Repair Welding .................................................................................................................. 17
14.9 Non-Destructive Testing (NDT) ......................................................................................... 18
14.10 Field Joint Coating ......................................................................................................... 18
15. Anodes ......................................................................................................................................... 18
16. Protection Coatings—Inspection and Repair .............................................................................. 18
17. Field Joint Coating ....................................................................................................................... 18
17.1 Properties .......................................................................................................................... 18
17.2 Storage and Handling of Material ...................................................................................... 19
17.3 Surface Preparation .......................................................................................................... 19
17.4 Application of Heat Shrink Sleeves & In-Fill Material ........................................................ 19
17.5 Inspection, testing and Repair ........................................................................................... 20
18. Risers ........................................................................................................................................... 21
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18.1 Installation ......................................................................................................................... 21
18.2 Testing ............................................................................................................................... 21
19. Pipeline Stabilization and Burial .................................................................................................. 21
19.1 Procedures ........................................................................................................................ 21
19.2 Rock Dumping ................................................................................................................... 22
19.3 Inspection/Testing ............................................................................................................. 22
20. Shore Approach ........................................................................................................................... 22
20.1 Included Activities .............................................................................................................. 22
20.2 Welding and Coating Requirements ................................................................................. 22
20.3 Documentation .................................................................................................................. 22
20.4 Trenching and Burial ......................................................................................................... 22
21. Post Lay Survey ........................................................................................................................... 23
21.1 Accuracy ............................................................................................................................ 23
21.2 Survey Vessel ................................................................................................................... 23
21.3 Documentation Requirements ........................................................................................... 23
22. Maximum Span Lengths and Span Correction ............................................................................ 24
23. Hydrostatic Testing ...................................................................................................................... 24
23.1 General .............................................................................................................................. 24
23.2 Material and Equipment .................................................................................................... 24
23.3 Filling the Pipeline ............................................................................................................. 25
23.4 Restriction Test ................................................................................................................. 25
23.5 Hydrostatic Pressure Test ................................................................................................. 25
23.6 Test Records ..................................................................................................................... 26
23.7 Repair of Defects ............................................................................................................... 26
23.8 Sealing the Pipeline ........................................................................................................... 27
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1. Scope
This specification specifies requirements for the installation of offshore pipeline. It applies to
rigid metallic pipeline on offshore, and shore approach where applicable.
2. References
Design, manufacture, performance and testing shall be in compliance with the following codes
and standard, except where otherwise specified. The following documents shall form an
integral part of this specification:
2.1 Local Regulation and Standards
Peraturan Menteri ESDM
No.15 Tahun 2008
Pemberlakuan Standar Nasional Indonesia Mengenai
Sistem Transportasi Cairan Untuk Hidrokarbond dan
Standar Nasional Indonesia Mengenai Perpipaan
Transmisi dan Distribusi Gas Sebagai Standar Wajib
Decree of Mines and Energy
300.K/38/M.PE/1997
Work Safety of Oil and Gas Distribution Pipelines
Decree 84.K/38/DJM/1998 Inspection Guidelines for Safety on Facilities, Equipment
and Technology Used in Oil and Gas and Geothermal
Activity
Regulation
06P/0746/M.PE/1991 Safety Audit to Inspection, Equipment and Technique
used In Oil and Gas Mining and geothermal Activities.
Regulation Number 11-
Year 1979
Working safely on Refinery and Processing Oil and Gas
Decree of Transportation
PM No. 68 year 2011
Alur-Pelayaran di laut
SNI 3473: 2011 Sistem Transportasi Pipa Penyalur untuk Cairan
Hidrokarbon dan Cairan Lain
SNI 3474: 2009 Sistem Penyaluran dan Distribusi Pipa Gas
2.2 Company Specification
The following COMPANY Specifications shall be applied to the subject work.
x PHEONWJ-W-PRC-0005 Pipeline Welding
x PHEONWJ-W-PRC-0012 Offshore Pipeline Design
x PHEONWJ-W-PRC-0013 Offshore Pipeline Surveying
x PHEONWJ-W-PRC-0014 Pipeline Test and Pre-commissioning.
x PHEONWJ-W-SPE-0001 Pipeline Induction Bends
x PHEONWJ-W-SPE-0003 Offshore Pipeline Crossing
x PHEONWJ-W-SPE-0005 Line Pipe
x PHEONWJ-W-SPE-0006 Pipeline Corrosion Protection Coating
x PHEONWJ-W-SPE-0007 Offshore Pipeline Weight Coating
x PHEONWJ-W-SPE-0009 Riser Corrosion Protection Coating
x PHEONWJ-W-SPE-0010 Pipeline Clamp
x PHEONWJ-W-SPE-0012 Pipeline Cathodic Protection
x PHEONWJ-W-SPE-0014 Pipeline Flanges and Fittings
x PHEONWJ-W-SPE-0015 Subsea Ball Valve
x PHEONWJ-W-SPE-0016 Field Joint Coating
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2.3 International Standards and Codes
Except where otherwise noted, the latest edition of the following codes and standards
should apply:
x API RP 1111 Design, Construction, Operation, and Maintenance of
Offshore Hydrocarbon Pipelines (Limit State Design)
x ASME B31.4 Pipeline Transportation Systems for Liquid
Hydrocarbons and Other Liquids
x ASME B31.8 Gas Transmission and Distribution Piping Systems
x DNV OS-F101 Submarine Pipeline Systems
x DNV-RP-F105 Free Spanning Pipelines
x DNV-RP-F109 On-Bottom Stability Design of Submarine Pipelines
x DNV-RP-F204 Riser Fatigue
x ISO 13623 Pipeline Transportation Systems
3. Definition of Terms
COMPANY PT. Pertamina Hulu Energi Offshore North West Java
CONTRACTOR The party that carries out all or part of the design, engineering,
procurement, construction, commissioning or management of a
project.
VENDOR The party that manufactures or supplies equipment and/or services
to perform the duties specified by CONTRACTOR.
4. Abbreviations
API American Petroleum Institute
ASME American Society of Mechanical Engineers
DNV Det Norske Veritas
ISO International Organization for Standardization
SNI Standar Nasional Indonesia
5. Health, Safety and Environment
The work shall be such that the risk to personnel and environment is as low as is reasonably
practicable.
6. Competence Assurance
The work shall be carried out by suitably qualified and competent persons.
7. Operational Organization
Operational organization shall be limited to the parties actually involved and be consistent with
the size or complexity of the project. The responsibilities and duties of each function shall be
clearly defined and published to minimize uncertainties and overlapping responsibilities. The
organization chart shall indicate, as appropriate, the functional links among the following:
a) COMPANY’s representative; b) Project and Operational management;
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c) towing vessels, mooring systems and marine spread
d) weather forecasting and support services;
e) advisory panel providing expertise as required;
f) HSE;
g) Statutory, regulatory and approving bodies.
Where transfer of responsibility to another organization (e.g. from fabrication to marine
operation, or onshore to offshore), smooth hand-over shall be carried-out. Changes of
personnel during critical stages of the operation shall be avoided. Personnel as a result of shift
changes shall be identified.
8. Design Data
Pipeline design data are given on the part of Project Design Basis. Environmental data are
given to CONTRACTOR for information only. CONTRACTOR shall obtain any verification or
additional data necessary to perform installation engineering and install the pipeline(s).
9. Installation Equipment
CONTRACTOR shall provide the number, type and capacity of equipment sufficient to install
the pipeline(s) in a safe and expedient manner.
CONTRACTOR shall demonstrate in the bid the adequacy of the equipment based on the
preliminary engineering analysis. Engineering shall take into account physical conditions,
including water depth, bottom soil properties and maximum environmental conditions
anticipated during installation. Pipeline stresses during installation and testing shall not exceed
those given in Section 10.1.3 of this Guidance.
CONTRACTOR shall clearly state all environmental criteria and stresses used in the
engineering. This shall include safety factors for equipment capacity and pipeline stresses.
Following completion of detailed installation engineering, CONTRACTOR shall review all these
safety factors and demonstrate their adequacy. Should any safety factor(s) prove to be
inadequate, CONTRACTOR shall upgrade equipment as necessary.
CONTRACTOR shall ensure that all equipment proposed in the project is adequate for the use
intended and will meet or exceed any and all applicable governmental, industry, environmental,
safety and health standards and regulations. It is CONTRACTOR’s responsibility to determine
existing regulatory requirements and ensure compliance.
COMPANY reserves the right to audit all marine vessels and other construction equipment
proposed for use by CONTRACTOR. Any equipment failing to comply with either the job
specifications or environmental or safety requirements, as determined by COMPANY, shall be
replaced or modified by CONTRACTOR prior to use.
10. Construction Engineering and Procedures
10.1 Engineering
Engineering shall demonstrate the feasibility, adequacy and safety of the intended
installation methods. It shall include the preparation of the following:
x Procedures
x Manuals
x Calculations
x Descriptions and drawings
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10.1.1. Covered Activities
The following activities (where applicable) shall be covered:
1. Pre-survey engineering (detail pre-survey for subsea positioning)
2. Survey and position fixing (including subsea positioning)
3. Seabed preparation
4. Pipeline crossing preparation and completion
5. Storage, handling and transportation of materials supplied by COMPANY
and CONTRACTOR
6. Pipe tracking
7. Pipelay (including start-up, laydown, temporary protection of existing
pipelines/cables and temporary installation aids)
8. Pipelay over crossings
9. Pipelay abandonment/recovery
10. Onshore approach installation method.
11. Riser Installation
12. Pipe welding (automatic and/or manual), including weld repair
13. Welder/welding machine operator qualification
14. Radiography
15. Radiographer qualification
16. Ultrasonic examination
17. Field joint coating and protection (HSS & In-fill material)
18. Corrosion coating repair
19. Concrete coating repair
20. Span correction
21. Trenching
22. Rock dumping
23. Flooding, cleaning and gauging
24. Hydrostatic testing
25. Dewatering
26. Anchor handling and anchor patterns (including layaway pipeline/crossings
and laydown)
27. Anchoring-up at any location (e.g., commencement of operations)
28. Dynamic positioning
29. Installation of mechanical subsea connection tools
30. Spool piece installation
31. Diving operations
32. ROV operations
33. Contingency operations
a) Wet/dry pipeline buckle
b) Incorrect positioning of line
c) Anchor wire failure or jettisoning
d) Pennant failure and buoy loss
e) Damage repair to existing pipelines/cables
34. Post / As-Build Survey
10.1.2. Analysis and Calculation
As a minimum, analyses and calculations for the following activities shall be
prepared by CONTRACTOR:
1. Detail route survey to determine the requirement (if any) for seabed
preparation
2. Pipelay static and dynamic stresses to determine operating pipelay
configurations, pipe stresses and lay tensions for all pipelay conditions
(including abandonment/recovery and startup/laydown)
3. Riser and subsea spool installation
4. Pipeline trenching
5. Allowable span
6. Rock dump installation design
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7. For the bottom pull method: pull forces, buoyancy, anchor forces,
equipment capacity and safety factors
8. For the tow method: pull, buoyancy, alignment and final positioning forces,
equipment capacity and safety factors
10.1.3. Stresses and Design Formulae
Allowable stresses and design formulae for installation shall be in accordance
with the equations and limits given in Table 10.1
Table 10.1 Allowable criteria for design and installation
Activities Maximum allowable criteria
Handling, shipping, storing
Static load stress ≤ ;
as per SNI 3474:2009 and SNI 3473:2011
Overbend while Pipelaying
inc. start-up, abandonment &
recovery*
Calculated strain ≤ 0.205 % ;
as per DNV OS F-101
Sagbend while Pipelaying
inc. start-up, abandonment &
recovery*
0.87 x SMYS ;
as per DNV OS F-101
Riser
Hoop stress ≤ 0.5 SMYS for Gas
Hoop stress ≤ 0.6 SMYS for liquid
Longitudinal stress ≤ 0.8 SMYS
Combined stress ≤ 0.9 SMYS
as per SNI 3474:2009 and SNI 3473:2011
Pipeline
Hoop stress ≤ 0.72 SMYS
Longitudinal stress ≤ 0.8 SMYS
Combined stress ≤ 0.9 SMYS
as per SNI 3474:2009 and SNI 3473:2011
10.2 Procedures
CONTRACTOR shall develop all procedures required for the installation, inspection and
testing of the pipeline system.
CONTRACTOR shall ensure that no damage is done to existing pipelines and cables by
submitting and following fully developed installation procedures and installing temporary
protection where necessary. Specific anchor patterns and placement procedures shall
be developed.
10.2.1. Installation Manuals
CONTRACTOR shall prepare and submit installation manuals to cover all
aspects of the installation. These manuals shall incorporate all engineering
calculations and procedures required to define the proposed method of
installation and to demonstrate compliance.
CONTRACTOR shall prepare and submit a full index of the installation manuals
for Company review and approval.
The manuals shall include the following elements:
1. Quality plan
2. Diving manuals
3. Safety manuals
4. Document and report formats
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5. Record and inspection forms
6. Calibration procedures and certificates
7. Equipment, rigging and material certificates
8. Final documentation formats
Individual Installation Manuals shall be prepared for the following, as applicable:
1. Pre-survey
2. Shore approach preparation and landline installation
3. Pipelay
4. Assemblies installation and tie-in
5. Post trenching and rock dump
6. Cleaning, gauging and hydrotest
7. Precommissioning
8. Shore makeup yard and facilities for bottom-pull and tow methods
9. Post Survey
11. Pre-lay Survey
11.1 General
Pre-lay Survey shall be in accordance with COMPANY specification PHEONWJ-W-PRC-
0013 Guidance on Offshore Pipeline Surveying clause 5.1
11.2 Scope Considerations
The scope of the prelay survey shall be determined by specific job site conditions.
Various factors shall affect the extent of prelay survey required along the proposed
pipeline route.
These include:
x Seabed contour & conditions
x Existing obstructions (such as foreign pipelines, cables, structures, etc.)
x Archeological features
x Government regulations
x Lay techniques
x Anchor patterns
12. Pipe Lay
12.1 Transportation
Company –furnished line pipe and materials transportation shall be in accordance with
COMPANY specification, PHEONWJ-W-PRC-0009 Guidance on Pipe Handling, Storage
and Transportation section 7.
CONTRACTOR shall assume responsibility and custody for all COMPANY-furnished
materials and shall develop and maintain an inventory and tracking system for these
items.
12.2 Alignment
The final on-bottom position of the pipeline shall be located within ±10 m (33 ft) of the
approved route centerline.
The pipeline shall be laid along the predetermined route except in the vicinity of the
platform approaches and crossings. There, the on-bottom placement of the pipeline
shall have a nominal spacing of 90 m (300 ft) from other objects and shall not be closer
than 30 m (100 ft) to any adjacent pipeline. Separation between a pipeline and a
platform to which the pipeline does not have a connection is 90 m (300 ft) minimum.
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The minimum on-bottom lateral radius shall be determined and analyzed for COMPANY
review and approval.
If the sea floor is too congested to adhere to these requirements, COMPANY shall be
advised in writing and a proposed pipeline alignment shall be presented to COMPANY
for approval.
12.3 Shallow Water Pipelines
On shallow water pipelines installation, CONTRACTOR shall install and maintain lighted
buoys marking the pipeline alignment at intervals of 305 m (1000 ft) or less to drive post
laying survey.
Coordinates locating each buoy to within a 3 m (10 ft) radius circle shall be provided to
COMPANY by CONTRACTOR.
CONTRACTOR shall install and maintain buoys to locate the exact positions of all
existing pipelines, cables, obstructions or obstacles within 305 m (1000 ft) in any
direction of the pipeline right-of-way and other activity areas.
All information obtained by CONTRACTOR on the location of the various obstructions
shall be made available to COMPANY.
In lieu of buoys, CONTRACTOR may use on-board real time positioning/navigation
systems, subject to Company approval. If used, such systems shall be operational
during the entire installation period.
12.4 Lay Operations
CONTRACTOR shall perform the following as applicable:
1. Provide temporary protection, as approved by COMPANY, to existing pipelines and
structures at startup, during lay and at lay down.
2. Identify and remove obstructions within the pipelay corridor. Seabed preparation
may be required, such as boulder removal and sand wave sweep.
3. Continuously monitoring barge movement and considering marine traffic during lay
operation to avoid clashing with another boat/barge
CONTRACTOR shall provide, for COMPANY review and approval, details of all buckle
detection methods, including internal buckle detectors, diver / ROV inspection beyond
the touchdown point or constant tension monitoring and recording.
Buckle detectors shall have a diameter 95% of the minimum internal diameter of the pipe
and shall be designed to ensure that no damage is caused to the internal surfaces of the
pipelines. The buckle detector shall be pulled continuously through the pipelines on a
cable of sufficient length to ensure the pipelines are in the final configuration on the
seabed when the buckle detector passes.
CONTRACTOR shall immediately notify COMPANY if the buckle detector system fails or
is suspected to have failed and when buckle detector loads are higher than expected. In
such circumstances, CONTRACTOR shall remove the buckle detector for inspection.
12.5 Pipelay Equipment Check
CONTRACTOR shall demonstrate to the satisfaction of COMPANY that all equipment,
including associated instrumentation and controls on the lay vessel, are of a proven
design, in good condition and in full working order. The equipment capabilities shall be
demonstrated prior to leaving base and at other such times as required by COMPANY.
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CONTRACTOR shall demonstrate the accuracy of tensioner and constant tension winch
load cells prior to lay. The tension control systems shall be shown to be accurate,
efficient and reliable.
Prior to start of pipelaying, CONTRACTOR shall check the height, location and condition
of each roller support on the pipelay vessel for adherence to drawings and installation
procedures.
Rollers shall be soft-faced with molded polypropylene or similar material. Worn rollers
and tensioner shoes shall be replaced.
The rollers on the stinger shall be inspected and tested (but not limited to be witnessed
by COMPANY) prior to the start of the pipe lay and at regular intervals thereafter. No
additional inspections may be required if the job is short in duration; e.g., one week.
The inspection may be conducted by ROV (Remote Operated Vehicle) or by air divers.
Deepwater stingers, which tend to be exposed to high environmental loadings, shall be
inspected regularly.
Prior to the start of pipelay, CONTRACTOR shall check and demonstrate that the
tensioners and roller supports are precisely aligned on the centerline of the pipe ramp.
CONTRACTOR shall demonstrate the operability of the pipelay stinger prior to the
commencement of pipelay. This shall include testing loadcells, cameras and other
monitoring equipment.
All testing and checking of installation equipment shall be witness by COMPANY.
12.6 Tension Control
The force applied by the pipe tensioning equipment for control of the suspended pipe
configuration shall satisfy the following requirements:
The lowest and highest level of tension in dynamic conditions, including environmental
loading on the suspended pipe length, shall be sufficient to keep the pipe stresses within
limits prescribed in Section 10.1.3 of this Guidance.
The tensioner squeeze pressure on the pipe shall be kept below a level where the pipe
coating or anodes may be damaged.
Prior to commencement of the pipelaying, CONTRACTOR shall provide COMPANY with
a schedule of proposed tensioner settings for application along the pipeline route.
12.7 Monitoring and Control of Pipe Configuration
The pipe tension, stinger depth and angle, pipe departure angle, maximum sagbend and
overbend stresses and the water depth shall be continuously monitored.
CONTRACTOR shall propose a procedure to determine the actual suspended pipe
configuration and location of the touchdown point. The determination shall consist of
graphs or tables prepared specifically for the pipeline and shall include the following:
x Effect of pipe tension and tension variation
x Effect of variation in submerged pipe weight including wet buckle
x Effect of current induced drag on the suspended pipeline for any direction of current
x Effect of changes in lay vessel attitude orientation and position
x Abandonment and recovery of pipe
x The effect of sea state
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The pipelay operation shall be monitored by ROV a minimum of twice per day,
depending on prevailing weather conditions. At critical locations, continuous monitoring
by ROV may be required.
12.8 Strip Chart Records
CONTRACTOR shall maintain a continuous paper strip chart record of the tension
applied to the pipe at all times during pipelaying abandonment and recovery operations.
The strip chart record shall be adequately marked with the time and date at periodic
intervals and indicate the operation being carried out.
The strip chart shall record the tension applied to the pipe by each of the tensioning
devices and the tension in the cable shall be used to tension the pipe during
abandonment and recovery operation.
Numerical tension values shall be recorded on the strip chart every hour.
12.9 Abandonment and Recovery of Pipeline
CONTRACTOR shall convey the limiting sea state and operational conditions at which
pipeline abandonment should commence as well as the elapsed time required to prepare
the pipeline for abandonment.
CONTRACTOR shall monitor deteriorating weather conditions and increasing sea states
when operating conditions may exceed the operational capabilities of the lay operation.
CONTRACTOR shall initiate procedures in time to complete abandonment before the
sea state reaches the limiting conditions for safety of the pipeline.
The operating sea state limitation for a lay vessel may not be representative of the
operating capabilities of the support vessels. For example, third generation North Sea
lay vessels can lay pipe in sea states in which the anchor handling tugs and pipe haul
vessels cannot operate.
12.9.1 Required Equipment
CONTRACTOR shall ensure that the pipelaying vessel is equipped to carry out a
pipeline abandonment and recovery procedure. The minimum equipment that
shall be carried in readiness is:
x Laydown winch
x Sufficient cable length
x Abandonment/recovery heads
x Instrumentation for monitoring the A/R winch tensions during abandonment
and recovery operations shall be provided and working properly. Subject to
be tested and witnessed by COMPANY.
12.9.2 Calculations
CONTRACTOR shall prepare abandonment/recovery calculations that determine
stress levels in the pipe on the barge, stinger and sagbend; the reactions on the
barge and stinger rollers; and the forces in the abandonment/recovery cable.
Abandonment/recovery calculations shall be performed for the most critical water
depth for each different pipe diameter/wall thickness/concrete combination.
The calculations shall indicate barge and stinger configuration, roller heights,
pipe profiles and the expected pipe tension for all stages of the
abandonment/recovery operations.
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All results shall be tabulated and presented in graphic form for ease of use by
field personnel and their subsequent usage shall become an integral part of the
approved procedures.
Stresses during abandonment and recovery shall comply with Section 10.1.3 of
this Specification.
12.9.3 Heads
Any pipe end lowered in the water shall have abandonment/recovery heads.
The installation and removal of abandonment/recovery heads shall be performed
by CONTRACTOR as part of the normal pipelaying operation.
Abandonment/recovery heads shall always be on board the pipe lay barge and
kept in ready status.
Abandonment/recovery heads shall be designed and fabricated by
CONTRACTOR and be subject to COMPANY approval.
The heads shall have all necessary contingency facilities required to flood and
dewater the pipeline. These facilities shall be protected from damage by a
protective cage or equivalent.
In addition, the heads shall be equipped with suitable Company-approved
marker systems to facilitate their relocation.
12.10 Wet and Dry Buckle Repair
Wet or dry repair shall follow approved procedures. CONTRACTOR shall make all
provisions to repair a pipeline in case of buckling by installing dewatering pigs, valves in
abandonment/recovery heads, etc. as required.
All buckles shall be repaired as soon as they are discovered, unless otherwise agreed by
COMPANY.
12.11 Diving
It shall be the sole responsibility of CONTRACTOR to ensure that all diving activities are
performed in accordance with statutory diving and COMPANY regulations.
12.12 Pipeline Initiation and Termination
At commencement and termination of laying, CONTRACTOR shall be required to
position the end of the pipeline within the target areas as shown on the contract
drawings. On completion of pipe lay down, CONTRACTOR shall accurately measure
the position of the pipe end. The method for taking these measurements shall be
reviewed and approved by COMPANY prior to its use.
1. CONTRACTOR shall move or adjust the length of the pipeline if the target area is
missed during pipeline initiation and termination operations. CONTRACTOR’s
proposed procedure for moving or length adjustment shall be reviewed and
approved by COMPANY prior to commencement.
2. Existing structures shall not be used for any purposes during pipeline initiation and
termination operations other than as specifically permitted by COMPANY.
3. During initiation and termination activities, CONTRACTOR shall use cables that do
not twist when tensioned. Alternatively, swivel connectors shall be used to prevent
the transmission of cable twist to the pipe.
4. The holding power of the deadman anchor or pile startup system shall be proved by
load testing to 1.5 times the maximum predicted load, holding for 30 minutes.
CONTRACTOR shall be responsible for clearing the seabed of deadman anchor or
pile startup system.
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12.13 Pipe Laying Records
At all times during pipelay operations, CONTRACTOR shall keep accurate pipe laying
records. These records shall contain the pipe as-laid sequential number with pipe
description data that include the following:
x Pipe identification number
x Length
x Wall thickness
x Negative buoyancy
x Whether an anode is fitted
x Any other information required by COMPANY
The records shall be kept in a neat and orderly manner on recording forms previously
approved by COMPANY as part of the pipeline installation procedures. At the end of
each day, the records, including the total length and number of pipes laid, shall be
tallied and two copies supplied to COMPANY.
The sequential pipe number, referring to the pipe and adjacent field joint, shall be
clearly painted in white on both sides of each pipe near the field joint. The paint shall
be suitable for long term immersion in sea water. The digits shall be a minimum of
150 mm (6 in) high.
13. Crossing
Installation for offshore pipeline crossing shall be in accordance with COMPANY specification
PHEONWJ-W-SPE-0003 Specification for Offshore Pipeline Crossing clause 8.
The following activities shall be undertaken:
1. A detailed survey of the crossing location shall be performed comprised of a bathymetric
and side-scan sonar survey, a sub-bottom profiling video survey and the procurement of
soil samples.
2. Contour plans and longitudinal sections shall be prepared, at scales to be approved by
COMPANY, displaying all pertinent data. These shall include the location of pipelines to
be crossed, depth of burial/degree of exposure, the condition of exposed pipeline and any
obstructions in the vicinity of the proposed crossing location.
3. Details of crossing design shall be finalized, based on detailed survey results and
calculated bearing pressure (including design of gravel and rock layers in rock dump) and
submitted for Company approval.
4. Obstacles shall be removed from the vicinity of crossings and the line to be crossed shall
be lowered if required.
5. After their installation, a survey of the installed mattresses shall be performed and "as-
installed" drawings submitted for Company approval. The separation between pipelines
shall be a minimum of 0.5 m (1.6 ft).
14. Welding
14.1 General
All welding and weld inspection shall be on accordance with COMPANY specification
PHEONWJ-W-PRC-0005 Site Technical Practice (STP) Pipeline welding
14.2 Equipment
Welding equipment specification shall be in accordance with COMPANY specification
PHEONWJ-W-PRC-0005 Site Technical Practice (STP) Pipeline welding clause 4.1
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14.3 Welding Consumables
Welding equipment specification shall be in accordance with COMPANY specification
PHEONWJ-W-PRC-0005 Site Technical Practice (STP) Pipeline welding clause 4.2
14.4 Welding Procedure Specification (WPS)
WPS shall be in accordance with COMPANY specification PHEONWJ-W-PRC-0005
Site Technical Practice (STP) Pipeline welding clause 5.3
14.5 Welding Procedure Qualification (WPQ)
Procedure qualification tests shall be in accordance with COMPANY specification
PHEONWJ-W-PRC-0005 Site Technical Practice (STP) Pipeline welding clause 5.3
14.5.1 Test Failures
Each test weld shall be non-destructively inspected in accordance with this
Specification. Should the soundness of the test weld fail to meet the
acceptance criteria, the weld shall not be submitted for mechanical testing.
Failures due to lack of fusion or due to cracking shall be investigated and
explained to the satisfaction of COMPANY. The WPS shall then be changed
to eliminate the problems before a new qualification test weld is made.
14.5.2 Specimen Requirements
Test specimen requirements and acceptance criteria for welding procedure
qualification shall be in accordance with API STD 1104 with the following
exception: pipe diameters 114 mm (4.5 in) OD and less shall require two
tensile strength tests and the additional requirements given on the Pipeline
Design. Failure shall require a change in the WPS unless a reason apart
from the WPS is accepted by COMPANY.
14.5.3 Hyperbaric Weld WPS
Welding procedure qualification for hyperbaric welding shall be conducted in
a pressure chamber using the equipment, gas composition and gas pressure
that accurately simulates both the equipment to be used and the anticipated
conditions during the actual tie-in.
14.5.4 Consumables
Welding consumables used for the procedure qualifications and production
welds shall be from the same batch. CONTRACTOR shall ensure that
sufficient welding consumables from a single batch are available for both the
welding procedure qualification and for production welding.
14.6 Qualification of Welders
Welder qualification shall be in accordance with COMPANY specification PHEONWJ-
W-PRC-0005 Site Technical Practice (STP) Pipeline welding clause 6
14.7 Production Welding
Design and preparation of a joint for production welding shall be in accordance with
COMPANY specification PHEONWJ-W-PRC-0005 Site Technical Practice (STP)
Pipeline welding clause 7
14.7.1 End Preparation
Pipe lengths shall be supplied with the standard API SPEC 5L, 30 degree
bevel configuration, unless otherwise specified on the Pipeline Design Basis.
For pipe-to-pipe welds where wall thickness changes are involved, the joint
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design shall be approved by COMPANY. The taper shall be 1:4 between
different wall thicknesses. Pipe bevels shall be checked by means of bevel
gauges at regular intervals to ensure uniformity in bevel profiles.
14.7.2 End Inspection
A visual inspection of the pipe ends, up to a distance of 50 mm (2 in) from the
ends, shall be carried out. Any pipe bevel showing harmful effects or
evidence of end area lamination exceeding the acceptance criteria in API
SPEC 5L, shall be cut back until the defect is removed and then re-bevelled.
After re-bevelling and removing 19 mm (3/4 in) or more from the pipe, the
pipe end shall be ultrasonically inspected using an approved procedure.
14.7.3 End Cleaning
All bevels shall be cleaned by power tools to a bright finish prior to lining up
the pipe.
14.7.4 Identification and Interior Cleaning
All welds shall be identified according to the sequential field joint number
painted on the pipe coating adjacent to the field joint.
Prior to pipe alignment, but after end beveling, the inside of each pipe shall
be cleaned to remove all debris and loose material.
Each joint shall be swabbed immediately prior to aligning with the pipeline to
remove all dirt, loose mill scale and other foreign substances inside the
pipeline.
The swab shall incorporate a steel ring, 6 mm (1/4 in) thick minimum, with a
diameter 3 mm (1/8 in) less than the nominal inside pipe diameter.
In the event that the support ring will not pass through a joint, that joint shall
not be incorporated in the pipeline. It shall be clearly marked as a reject, and
then removed from the work site.
14.7.5 Alignment
Pipe end alignment shall be in accordance with COMPANY specification
PHEONWJ-W-PRC-0005 Site Technical Practice (STP) Pipeline welding
clause 7.2.
14.7.6 Pre- heat treatment
Pre-heat treatment shall be in accordance with COMPANY specification
PHEONWJ-W-PRC-0005 Site Technical Practice (STP) Pipeline welding
clause 7.11.1. Preheat and interpass temperatures shall be in accordance
with COMPANY Approved WPS
14.7.7 Post-Weld Heat Treatment (PWHT)
Post-heat (including PWHT) shall be in accordance with COMPANY
specification PHEONWJ-W-PRC-0005 Site Technical Practice (STP) Pipeline
welding clause 7.11.2.
14.8 Repair Welding
Repair and defects removal shall be in accordance with COMPANY specification
PHEONWJ-W-PRC-0005 Site Technical Practice (STP) Pipeline welding clause 10.
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14.9 Non-Destructive Testing (NDT)
NDT procedures shall be in accordance with COMPANY specification PHEONWJ-W-
PRC-0005 Site Technical Practice (STP) Pipeline welding clause 10.
14.10 Field Joint Coating
Field joint coating material, minimum procedure requirements, joint preparation,
coating and application procedures, and testing shall be in accordance with
COMPANY specification PHEONWJ-W-SPE-0016.
15. Anodes
Anodes installation shall be in accordance with COMPANY specification PHEONWJ-W-SPE-
0012.
16. Protection Coatings—Inspection and Repair
The inspection and repair of corrosion protection coating from damage during all phase of the
installation and prior to lowering the pipe into the water shall be in accordance with COMPANY
specification PHEONWJ-W-SPE-0006 and accordance with manufacturer recommendation.
CONTRACTOR shall complete the repair by applying approved filler placed in a pre-installed
metal form to round out the joint coating to the dimensions of the concrete. These repairs shall
be completed prior to the overbend area with adequate curing time provided.
The decision to repair damaged pipe shall be taken on a case-by-case basis. Concrete weight
coating repairs shall be in accordance with COMPANY specification PHEONWJ-W-SPE-0007
and accordance with manufacturer recommendation. Repairs are not required on a joint if:
1. The total damaged area does not exceed 300 cm2 (46.5 in2)
2. The maximum depth of a damaged area does not exceed 25 percent of the total concrete
thickness
3. There is less than 20 total damaged areas
Repeated weight coating damage shall be immediately investigated so that the cause can be
identified and remedial action taken to COMPANY’s satisfaction.
17. Field Joint Coating
17.1 Properties
The VENDOR shall provide a heat shrink sleeve which has a proven track record in
offshore pipeline construction and suitable for a minimum 10 year design life which is
suitable for a sustained operating temperature of 200°F (93.33°C) in a subsea
environment. The VENDOR shall demonstrate the track record by submitting
performance test data, including but not limited to peel strength, cathodic disbandment
and ageing for CONTRACTOR evaluation order to have COMPANY approval.
With heat shrink sleeve as the infill system, the sleeve shall be demonstrated to be
compatible with the corrosion coating and its application procedure. The dimensions
and type of the shrink sleeve shall be proposed by the VENDOR for CONTRACTOR
evaluation in order to have COMPANY approval and shall be capable of completely
covering the exposed pipe and coating cut back with a minimum coating overlap at
each side of the joint of 150 +20/-0 mm.
The VENDOR shall carry out a procedure qualification test for COMPANY approval, to
meet the field joint coating requirements..
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17.2 Storage and Handling of Material
Sleeve storage and application shall be in accordance with Manufacturer’srecommendations with the following minimum requirements:
1. On delivery of the material packages, all packages shall be visually inspected for
absence of obvious damage, integrity and acceptance for use in the project.
2. The materials shall be stored is suitable covered warehouses, raised from the
ground in order to avoid flooding, sheltered from direct sunlight and rain and shall
be stored away from any external heat source.
3. Sleeve materials shall remain in their packaging until required and shall be stored
in a dry protective environment at less than 35°C.
4. All materials shall be stored at all times in accordance with the Manufacturer’srecommendations.
5. When the materials are removed from the warehouse and delivered on the work
site, the materials shall be kept under cover protected from rain and direct sunlight,
shall be kept well closed in their original packages and raised up from the ground.
6. Materials shall be used and applied before their expiry date otherwise they shall be
discarded.
17.3 Surface Preparation
1. Surface preparation shall be in accordance with the Manufacturer’s requirementsat the time of sleeve application. Level of surface preparation required to achieve
required sleeve properties once installed shall be confirmed based on pre-
qualified testing results.
2. Prior to the commencement of the surface preparation, a visual inspection shall be
performed in order to detect any presence of defects on the field joint coating area.
3. All weld spatter, weld slag, sharp edges, etc. shall be removed from the surface of
the pipe.
4. Any contamination, visually detected, such as grease, oil, and similar
contaminants, shall be removed prior to the cleaning using a suitable solvent
according to the SSPC SP 1 specification or any other suitable mean (detergents,
water, power brushes, etc.) depending on the convenience.
5. The surface of the field joints shall be cleaned by power tool cleaning as per the
SSPC-SP-3 specification in order to obtain a minimum finishing grade of St 3 as
per the ISO 8501-1 standard.
6. After cleaning, the cleaned field joint shall be thoroughly inspected for surface
imperfections such as slivers, scabs, burrs and sharp edged defects.
7. The total area of the corrosion coating to be covered shall be wiped clean and
abraded using emery cloth prior to application. Each end of the corrosion coating
adjacent to the weld shall be feathered to exclude air pockets as the sleeve and
tape is applied.
8. Following shrinking of the sleeve, and cooling to less than 95°C, the total surface
area shall be made free of wrinkles or voids with particular attention paid to the
weld seam, corrosion coating cutback and closure strip/ overlap areas.
17.4 Application of Heat Shrink Sleeves & In-Fill Material
Heat shrink sleeves shall be applied in accordance with Manufacturer’s instructionsand in accordance with approved procedure.
Application of the in-fill material shall be performed only on concrete coated pipes after
acceptance of installation of the heat shrink sleeve. Non-reusable metallic mould shall
be used for application of the in-fill material and minimum four bands shall be used to
fix the mould onto the field joint area. Application of in-fill material shall be performed in
accordance with approved procedure and/or in accordance with the polyurethane foam
Manufacturer’s instructions.
Contractor shall fully qualify field joint coating at the early phase of the detailed
engineering. The qualification shall include at least:
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x Qualification of product material
x Qualification of applicator
x Qualification of application procedure
x Qualification in condition of use of the field joint
If necessary, preheating can be used to heat the joint up. The steel temperature locally
on welds shall not exceed 1500C
The temperature of the joint shall be at least 3°C above the dew point. At the time of
application, the temperature at the surface of the joint shall be within the temperature
range specified by the MANUFACTURER. The temperature of the joint shall be
monitored using suitable means in order to make sure that the application conditions
are fully satisfied (steel substrate and plant applied coating). During bad weather (rain,
wind, etc.) cleaning operations may only continue if effective protective awnings are
installed.
17.5 Inspection, testing and Repair
The inspection, testing and repair of heat shrink sleeves shall be in accordance with
Table 12.1 and the following requirements:
1. Surface preparation shall be inspected visually to ensure compliance with section
12.2 of this specification.
2. The field joint surface area to be covered by the sleeve shall be uniformly
preheated, if required, to the Manufacturer’s temperature requirements. A suitabletemperature probe shall be used to verify that the required preheat condition has
been achieved.
3. Immediately after shrinking, the entire surface of the sleeve shall be inspected for
surface flaws. Where present, these shall be removed in accordance with a
procedure developed by VENDOR and approved by CONTRACTOR.
4. Adhesive flow shall be evident on both sides of the sleeve.
5. Applied sleeves shall be subjected to a standard Peel Test conducted in
accordance with ASTM D-1000. Repairs must be in accordance with the
Manufacturer’s instruction and to the satisfaction of COMPANY. 6. Field joints shall be holiday detected using approved holiday detector set to a test
voltage in accordance with manufacturer’s recommendations. 7. Calibration of the holiday detector shall be performed as necessary.
8. Heat shrink sleeves, once applied, shall not be repaired. In case one holiday is
detected with holiday detector or the application of the heat shrink sleeve did not
pass visual inspection in accordance with this specification, a new heat shrink
sleeve shall be applied
9. Repair of The Field joint in-fill material, Maximum two voids per each field joint
having 75 mm in diameter or less and whose depth at the same time does not
exceed 50% of the concrete coating thickness on that pipe shall not be repaired.
Other voids shall be repaired using the same in-fill material as during the
production.
10. In case the in-fill material is damaged in a manner that it cannot be repaired, the
in-fill material (and the heat shrink sleeve if damaged during the removal of the in-
fill material) shall be removed from the field joint area. In case the heat shrink
sleeve has to be removed together with the in-fill material, the field joint coating
area shall be re-cleaned and re-coated in accordance with this specification.
11. Inspection and testing equipment shall be calibrated as required by
CONTRACTOR.
12. The VENDOR shall submit equipment calibration procedures for CONTRACTOR
review in order to have COMPANY for approval.
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Table 17.1 Inspection and Testing of Heat Shrink Sleeves
ITEM TEST TEST LOCATION ACCEPTANCE
FREQUENCY CRITERIA
Surface Preparation:
Visual Each Field Joint
100% of Field Joint
Surface Area
Free of contaminates,
surface prepared to
Manufacturer’s requirement
Preheat Temperature Each Field Joint Check at 3,6,9,12
o’clock position
Uniform Temperature ≥specified manufacturer
minimum
Shrink Sleeve Bond
to Weld Margin Each Field Joint
100% of Field Joint
Surface Area
Uniform Shrinkage and
Free of Surface Flaws
Peel Test During Qualification
Test 12 o’clock Position 2.75N/mm(ASTM D1000)
Holiday Detection Each Field Joint 100 % of Field Joint
Surface Area
Absence of Holidays at test
voltage
18. Risers
CONTRACTOR shall fabricate risers in accordance with this Specification and the job
specifications. All riser bends shall have a minimum radius of five pipe diameters. Girth welds
shall be no closer than 1.5 m (5 ft) from the centerline of any riser clamp.
18.1 Installation
CONTRACTOR shall provide sufficient bracing at installation to prevent the cathodic
protection insulating flange from supporting the riser weight.
Riser clamps shall be installed in accordance with this Specification and the job
specifications. If the clamps are to be installed on an existing structure, all marine
growth on the structure shall be removed from the structure surface where the clamp is
to be located immediately before installation.
If the riser is installed offshore, it shall be installed in accordance with procedures
approved by COMPANY.
18.2 Testing
Each riser shall be hydrostatically tested in accordance with COMPANY guidance
PHEONWJ-W-PRC-0014.
19. Pipeline Stabilization and Burial
Pipelines shall be placed below the seabed as required by applicable local marine pipeline
codes and COMPANY.
CONTRACTOR shall bottom-stabilize and/or bury the pipeline where required in accordance
with the job description and this Specification.
CONTRACTOR shall use sand/cement bags, rock dumping, grout mattresses, trenching,
jetting or other Company approved methods to fulfill the requirements of this Section.
Sandbags used for stabilization shall be 3:1 sand/cement mix. The ends of the bags shall be
folded and sewn.
19.1 Procedures
CONTRACTOR shall include detailed procedures, design drawings and calculations
relating to pipeline trenching, jetting, sandbagging or rock dumping operations in the
appropriate Installation Manual.
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Design and procedures for jetting and trenching operations shall ensure that excessive
stresses are not imposed on the pipeline due to the formation of unsupported spans or
contact between the pipeline and trenching/jetting equipment.
19.2 Rock Dumping
Rock dumping shall be designed so that impingement damage to the pipeline is
minimized. Where necessary, a sand pad shall be placed over the line prior to rock
placement.
Rock size shall be selected to ensure that the final cover profile over the pipeline and
the fill around or under the line can be achieved.
19.3 Inspection/Testing
Post-lay trenching and jetting operations shall be continuously monitored by ROV,
fixed video cameras or divers.
Inspection using ROV or other approved methods shall be made following
burial/stabilization activities to verify that the design requirements have been met.
Hydrostatic testing shall be accomplished after stabilization/burial is complete.
Verification of pipeline integrity after laying but before stabilization/burial shall be
performed as required by COMPANY.
20. Shore Approach
20.1 Included Activities
Shore approach activities shall consist of the following, as applicable:
x Pulling a section of pipeline to shore
x Trenching in foreshore including surf zone and beach
x Dredging
x Burial, using existing bottom soils or borrow materials, including rock protection
x Sheet piling, cofferdams and other temporary works
x Removal and replacement of existing shore rock protection
x Provision of signs marking onshore line route
x Fencing and securing on shore route and construction area
x Restoration of onshore facilities and topography to original conditions
x Other activities specific to the site and project
20.2 Welding and Coating Requirements
Requirements for field joint welding and coating shall be identical to the requirements
given for the offshore line unless otherwise specified.
20.3 Documentation
CONTRACTOR shall provide details of proposed equipment for pulling the shore
approach section of line in accordance with Section 4 of this Specification. Refer to
Section 7.11, Item 4 of this Specification for capacity of deadman anchors.
In addition to the procedures, installation manuals, etc. required by Section 5,
CONTRACTOR shall provide similar documentation for the shore approach as
applicable to the specific project and as required by the job specifications.
20.4 Trenching and Burial
Requirements for trenching, burial, rock protection and all other activities given in this
Section shall comply with the project specifications and drawings.
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Trenching and burial requirements shall strictly comply with applicable CFR and/or any
other authority having jurisdiction.
Any obstructions encountered shall be immediately brought to COMPANY’s attention
for resolution. CONTRACTOR shall take every precaution not to damage existing
obstructions, but in the event of their damage, shall replace or repair them at
contractor’s cost to COMPANY’s satisfaction.
21. Post Lay Survey
Post lay survey shall be in accordance with COMPANY specification PHEONWJ-W-PRC-0013
Guidance on Offshore Pipeline Surveying.
CONTRACTOR shall perform a post lay survey of the pipeline, risers, tie-ins, etc. in order to
document the as-built condition of the pipeline system. This survey shall use ROVs equipped’
with video and position-fixing equipment and/or divers where applicable. The activity shall
include, but not be limited to, the following:
x Perform a video survey of the pipeline and subsea assemblies to determine the as-built
condition.
x Determine any adverse condition such as spanning, proximity of obstructions, etc.
x Construct details of crossings.
x Remove all construction debris from the seabed.
x Perform an acoustic scanning survey of buried sections of the pipeline.
x Perform a final as-built survey and prepare as-built drawings for the entire pipeline route
showing all pertinent data and submit to COMPANY for approval.
21.1 Accuracy
x Accuracy of the survey shall be ±3 in (±1.0 ft) in the horizontal planes.
x CONTRCATOR shall resurvey any areas where post lay conditions such as
spanning or insufficient burial depth were previously identified to verify repairs.
21.2 Survey Vessel
x CONTRACTOR shall provide a survey vessel(s) to perform the as-built survey and
to assist the lay and support vessels during pipeline installation activities.
x The survey vessel shall be continuously on site during the specified operations to
monitor the as-laid position of the pipeline system; both in the horizontal and the
vertical plane.
21.3 Documentation Requirements
x As-built video surveys shall show both sides of the line and verify the on-bottom
conditions, crossing separation, joint markings where visible, etc. CONTRACTOR
shall document results of the survey activities and transmit them to COMPANY on
a daily basis.
x CONTRACTOR shall prepare scale drawings of all crossings, tie-ins, spans, etc.
showing final configuration, mat or rock dump profiles and other explanatory data.
x CONTRACTOR shall prepare as-built survey plots showing final horizontal and
vertical pipe positions, locations of important features such as anodes, crossings,
tie-ins, etc. and other information as requested by COMPANY or required by local
regulatory agencies.
CONTRACTOR shall provide COMPANY with two copies of all survey video tapes. The tapes
shall be annotated to show time, date, position and project name. Voice-over commentary may
be added to further describe the tape contents. Each tape shall be accompanied with a written
log describing contents and summarizing major conditions documented on the video.
CONTRACTOR shall also provide an index referencing the areas shown on each tape.
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PHEONWJ-W-PRC-0011 Rev.0 Page 24 of 27
Paper Copies are Uncontrolled
22. Maximum Span Lengths and Span Correction
Design and Operation of Span correction shall be in accordance with COMPANY specification,
PHEONWJ-W-PRC-0010 Guidance on Pipeline free span correction. Maximum permissible
span lengths for pipelines shall be calculated in separate Pipeline Free span analysis.
CONTRACTOR shall be responsible for surveying the pipeline immediately after pipelay to
ensure that no freespan lengths exceed the maximum permissible after pipelaying.
All spans greater than maximum permissible span length shall be rectified prior to filling the
pipeline with water.
In the event that excessive spans are observed, CONTRACTOR shall rectify the spans by
"jetting-in" the pipeline, placement of inflating concrete bags or by suitably graded gravel/rock
dumping.
23. Hydrostatic Testing
23.1 General
Pipeline testing (including hydrostatic testing) shall be in accordance with COMPANY
guidance PHEONWJ-W-PRC-0014.
CONTRACTOR shall clean, gauge and hydrostatically test the pipeline and risers in
accordance with this Section. The test pressure shall be as specified on the Project
Design Basis at a test temperature between 2-38°C (40-100°F).
x CONTRACTOR shall submit for approval a detailed step by step procedure and
testing operations schedule a minimum of six weeks prior to the start of the test.
The procedure shall state the required equipment type and size, number and type
of pipeline pigs, inhibitor type and quantity and a description of the test monitoring
equipment.
x Prior to the start of the hydrostatic test, all riser clamp bolting shall be loose and all
riser elbow braces shall be removed. Following the completion of the test, all riser
clamps shall be tightened and the riser stop ring shall be in contact with the fixed
clamp.
x The testing operations shall be conducted diligently and thoroughly in a safe
professional manner in accordance with COMPANY approved pipeline testing
practices. Any work by CONTRACTOR or test conditions deemed by COMPANY
to be unsafe shall be corrected. The testing operations shall not continue until the
unsafe conditions have been corrected to the satisfaction of COMPANY. Nor shall
CONTRACTOR receive additional compensation for time lost due to unsafe
conditions.
x If testing is subcontracted, CONTRACTOR shall be responsible for supervising the
testing operations. COMPANY shall witness and approve all tests.
x The resulting stress from the hydrostatic test pressure, combined with other
relevant simultaneously acting stresses on the pipeline, shall not exceed 96
percent of SMYS.
23.2 Material and Equipment
CONTRACTOR shall furnish all materials and equipment for testing, including the
following items:
x Temporary pig launchers and receivers ® Cleaning and gauging pigs
x Chemicals and inhibitors
x Test instruments
x Water strainers and filters
x Fill and pressure pumps
x Meters
x Air compressors
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PT. PHE ONWJ Guidance on Offshore Pipeline Installation
PHEONWJ-W-PRC-0011 Rev.0 Page 25 of 27
Paper Copies are Uncontrolled
x Scrapers,. extra scraper brushes and cups
x All piping incidental to filling, sectionizing and transferring of water
x Portable communications equipment for use by CONTRACTOR and COMPANY
During the testing operations, CONTRACTOR shall furnish a weather proof enclosure
for pressure recorders, calibration equipment and test personnel at the data collection
site of each test section. CONTRACTOR shall also furnish sufficient lighting in the
compressor pump enclosure and test header areas. during periods of darkness when
testing operations are in progress.
23.3 Filling the Pipeline
All water injected into the pipeline shall be clean and free from suspended matter.
x A meter of sufficient size and accuracy shall be used to measure the :quantity of
water injected into the test section.
x Before water is injected into the pipeline, suspended matter in the water shall be
extracted by a filter capable of removing 99 percent of all particles 92 T (3.6 mil) in
diameter and larger or equivalent to using a 100 x 100 T (4 x 4 mil) wire-mesh
screen.
x If foreign material is pumped into the line because of faulty equipment or careless
work, CONTRACTOR shall flush the line with clean. water at no cost to
COMPANY.
x The test water may be analyzed by COMPANY to determine its suitability for use
in the testing operations and to. determine the water treatment requirements.
- Corrosion inhibitor, oxygen scavenger and biocide treatment may be used
except where environmental discharge problems of hydrotest water prevent
their use.
- Chemical treatments shall be reviewed and approved by a COMPANY early in
the project to facilitate timely injection of the chemicals into the system.
- The required chemical additives shall be injected with the water by
CONTRACTOR (immediately behind the gauging scraper pig) in
concentrations sufficient to protect the pipeline for a minimum of 6 months.
Any nearby offshore installations involved in water-making operations shall
also be notified.
23.4 Restriction Test
After running the cleaning scraper, a gauging scraper with an aluminium gauging plate
shall be forced through the line at a minimum velocity of 1 m/s (3 ft/sec).
x The gauging plate shall be no less than 6 mm thick with a diameter not over 95
percent of the minimum ID of the pipe to be tested.
x If the scraper becomes lodged and will not move by the water pressure,
CONTRACTOR shall repair the pipeline as needed to permit the scraper to make a
complete transit at the specified velocity.
Before CONTRACTOR can consider the line as having passed the test, the sizing
plate used shall be presented to COMPANY and written acceptance of the adequacy
of the restriction test shall be obtained. A deformed, bent or severely nicked plate shall
be evidence of test failure, at the discretion of COMPANY.
23.5 Hydrostatic Pressure Test
On satisfactory completion of the restriction test, CONTRACTOR shall hydrostatically
test each pipeline and riser in accordance with the following test procedures. Test
pressure and duration are given on the PHEONWJ Data Sheets for this Specification.
1. The pressure shall be raised to the test pressure specified on the PHEONWJ Data
Sheets for this Specification, allowed to stabilize then held for 15 minutes. The rate
of pressure increase shall not exceed 100 kPa (15 psi) per minute during all
operations.
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PT. PHE ONWJ Guidance on Offshore Pipeline Installation
PHEONWJ-W-PRC-0011 Rev.0 Page 26 of 27
Paper Copies are Uncontrolled
2. The pressure shall be lowered to approximately 25 percent of test pressure,
allowed to stabilize then held for 15 minutes. Rate of pressure decrease shall not
exceed 200 kPa (30 psi) per minute during all operations.
3. The pressure shall be raised to an amount approaching the test pressure and
again allowed to stabilize before it is finally raised to the test pressure. The
pressure shall not decrease more than 0.2 percent after compensating for
temperature. None of this or the foregoing shall be included in the test duration.
4. Water shall be injected or withdrawn from the test section to maintain pressure
within the specified limits. The volume of these injections and/or withdrawals shall
be measured and recorded.
5. Pressure-volume-temperature (PVT) calculations shall be performed to show any
observed pressure loss due to a temperature change or a leak.
6. A pressure recorder and temperature recorder shall be used to continuously record
the test pressure, fluid temperature and ambient temperature. In addition,
pressures shall be read and recorded to the nearest 7 kPa (1 psi), using a
deadweight tester furnished by CONTRACTOR. The pressure shall be recorded
every 15 minutes until it has stabilized; then it can be recorded every 30 minutes.
23.6 Test Records
CONTRACTOR shall furnish all testing equipment, 24 hour recording instruments and
all necessary supplies as well as maintain accurate and permanent records. The
testing and recording equipment shall be subject to Company approval. Pressure
recordings shall serve only as information data and may not be used to determine
pressure drop for pipeline leakage. Tests shall not be accepted until the specified test
duration can be recorded without pressure loss exceeding 0.2 percent of specified test
pressure.
x All recorders and dead weight testers shall be calibrated immediately prior to use.
Calibration certification shall be provided for each recorder and dead weight tester
used. Recorders shall have calibration verified following the hydrotest. Post-test
calibration failure for any recorder shall be grounds for the hydrotest to be rejected
by COMPANY.
x A time-pressure plot and pressure-volume plot shall be made during’, the pressure
test to visually record its progress. This record shall be made using the dead
weight pressure measurements and shall be used to determine if the test is
satisfactory.
x All records, data and charts clearly marked with the following information shall be
furnished to COMPANY:
- COMPANY authorized representative
- Testing contractor’s name and authorized representative
- Description of facilities tested
- Date and time of test
- Test pressure and duration Test medium used
- Explanation of any pressure discontinuities that appear on any chart
- Signatures of COMPANY’s and the testing contractor’s authorized
representatives
23.7 Repair of Defects
Failures in the line disclosed by the loss of pressure shall be located and repaired by
CONTRACTOR.
CONTRACTOR shall, at contractor’s expense, repair all defects found whether resulting
from inferior workmanship or from defective materials furnished by CONTRACTOR.
Repairs by CONTRACTOR on defective materials furnished by COMPANY shall be
compensated on a mutually acceptable basis.
After repairs have been made, the pressure test shall be repeated until the pipeline and
risers have been determined acceptable by COMPANY.
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PT. PHE ONWJ Guidance on Offshore Pipeline Installation
PHEONWJ-W-PRC-0011 Rev.0 Page 27 of 27
Paper Copies are Uncontrolled
23.8 Sealing the Pipeline
After acceptance of the hydrostatic strength and leak test, the pressure shall be released
until atmospheric pressure has been reached.
Reduction of pressure shall be conducted slowly (205 kPa [30 psi] per minute maximum) to
prevent severe piping vibration.
CONTRACTOR may be required to obtain samples of the test water to confirm that the
concentration of chemicals is adequate to protect the pipeline from internal corrosion for a
minimum of 12 months.
On Company approval of the chemical concentrations, CONTRACTOR shall seal the risers
with weld caps at the top of the jacket.
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