Specification for Subsea Structure and Spool Installation Ps4

8/9/2019 Specification for Subsea Structure and Spool Installation Ps4

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SPECIFICATION FOR

SUBSEA STRUCTURE AND SPOOL INSTALLATION

WEST NATUNA PIPELINE PROJECT

INDONESIA TO SINGAPORE

PREPARED FOR

WEST NATUNA GROUP

INTEC PROJECT H-0879.01

MARCH 1998

0 30-Mar-98 ISSUED FOR CLIENT APPROVALLSW CDK RJP WNG

B1 27-Mar-98 ISSUED FOR CLIENT REVIEWLSW CDK RJP WNG

REV. DATE DESCRIPTION BY CHKD APPD CLIENT

SPECIFICATION NO.

8791/09-PS4


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Specification No. 8791/09-PS4Rev. 0/Page i

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TABLE OF CONTENTS

1. GENERAL......................... .................................................. .....................................................1

2. PROCEDURES ................................................................ ........................................................1

3. LIFTING AND TRANSPORTATION ................................................................ ..................1

4. SEABED PREPARATION ................................................................ .....................................2

5. STRUCTURE INSTALLATION ................................................................ ...........................2

6. SPOOL FABRICATION.................................................................... .....................................3

7. SPOOL INSTALLATION ................................................................ ......................................5

8. SURVEY ................................................................ ........................................................ ...........5

9. RECORDS ................................................................ ................................................................ 6

(This Specification consists of 8 pages)


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Specification No. 8791/09-PS4Rev. 0/Page 1 of 6

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1. GENERAL

This specification defines minimum quality and technical standards governing theinstallation of subsea structures and the fabrication, testing and installation of field-fitspools. This specification is to be used in conjunction with the following documents:

Design Basis Memorandum 8791/02-DBM001General Specification 8791/09-GS1 - Definitions and Specification DirectoryGeneral Specification 8791/09-GS2 - Quality Assurance / Quality ControlGeneral Specification 8791/09-GS3 - General Offshore SpecificationGeneral Specification 8791/09-GS4 - Offshore SurveyGeneral Specification 8791/09-GS5 - Offshore Positioning

2. PROCEDURES

CONTRACTOR shall prepare for COMPANY approval detailed procedures, drawingsand associated calculations describing methods used to control installation operations.The procedures listed below shall be submitted as a minimum:

Structure handling and seafasteningsStructure installation and pilingSpool fabricationSpool metrologySpool handling and seafasteningsSpool installation

Welding procedures and qualificationRadiography and NDE

2.1 Procedures shall be supported by appropriate calculations showing compliance withrelevant Codes, Standards and SPECIFICATIONS, identifying the calculation basis andany assumptions used. CONTRACTOR shall furnish all inputs and outputs for computer

programs and calculations.

3. LIFTING AND TRANSPORTATION

CONTRACTOR shall provide a suitable lifting and transportation equipment to ensurecompliance with relevant codes, standards and specifications.

3.1 CONTRACTOR shall only lift the structure and spoolpiece in accordance withCOMPANY-approved procedures, using lifting points designed for dynamic loads.

3.2 CONTRACTOR shall demonstrate by calculation that all spreader bars, braces, liftingclamps, padeyes, slings, ratchets, shackles and other lifting equipment are capable of


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holding the load in a dynamic situation. No lifts shall be undertaken before COMPANYhas approved the calculations.

3.3 Lifting points shall be designed to spread the load such that the structure and/or spoolpiece are balanced and that no one lifting point is overloaded. This may beachieved by using ratchets or other equipment subject to COMPANY approval. Thelifting points shall be positioned such that the maximum dynamic stresses in the pipingand pipeline components are less than 72% SMYS.

3.4 CONTRACTOR shall seafasten the structure and spoolpieces during transportation atsea. All seafastenings shall be surveyed and approved by a third party prior totransportation. All supports, outriggers or other temporary fixtures shall be designed andcalculated to withstand dynamic loads. All critical support welds shall be examinedusing magnetic particle techniques. Defective welds shall be re-strengthened.

3.5 CONTRACTOR shall use only certified lifting equipment. Equipment with expiredcertification or equipment that has suffered any damage since certification shall not beused.

4. SEABED PREPARATION

CONTRACTOR shall inspect the seabed prior to overboarding structures and spools.The seabed shall be flat and smooth. Any seabed irregularies and debris, natural or otherwise which may interfere with the footprint of the structure and spoolpieces shall beremoved to COMPANY satisfaction.

5. STRUCTURE INSTALLATION

CONTRACTOR shall only install structures during a period of calm weather and whenno adverse weather is forecast for the installation period.

5.1 Any coating damage shall be repaired in accordance with COMPANY-approved procedures after removal of seafastenings.

5.2 CONTRACTOR shall install structures to the following tolerances:

Within 2.5 m of target locationWithin 1 orientationWithin 3 horizontal plane

If these tolerances are exceeded, CONTRACTOR shall reposition the structure and/ or perform additional seabed preparation.


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5.3 CONTRACTOR shall advise COMPANY when the structure is ready to be lifted. Nolifting operations shall commence without COMPANY approval.

5.4 During lifting operations, the structure shall be prevented from rotation and its depthabove the seabed shall be monitored.

5.5 The structure shall not be detached from the lifting equipment until CONTRACTOR demonstrates to COMPANY satisfaction that it conforms to specified installationtolerances.

5.6 CONTRACTOR shall perform a pile driving analysis to confirm suitability of the piledriving equipment for the pile size and soils encountered.

5.7 CONTRACTOR shall calculate a stroke estimation for the predicted soils. If the actualstroke count is less than 50% of the stroke estimation, it shall be assumed that the soils

are weaker than predicted and the pile shall be re-designed to suit.

5.8 The pile hammer shall be purpose built and have a mechanism that ensures that in theevent of hydraulic failure, the pile gripper jaws remain locked shut.

5.9 Once piling has been completed, the structure shall again be checked for installation towithin the required tolerances.

5.10 The piles shall be cut to length and pinned to the structure using a COMPANY-approvedmethod.

6. SPOOL FABRICATION

CONTRACTOR shall perform the final welds on the spoolpiece in compliance withCOMPANY-approved metrology results. The metrology shall be performed bothacoustically and by using taut wire systems. When the spoolpiece is welded and coated,it shall be hydrotested prior to installation.

6.1 Each pipe and bend shall be internally cleaned and gauged, by a COMPANY approvedmethod immediately prior to welding, to remove dirt, loose rust and to ensure acceptableovality. Gauging plates shall be sized to comply with Specification For Cleaning,Gauging and Hydrostatic Pressure Testing, Specification 8791/09-PC1. Pipe failing the

pre-installation gauging test shall be rejected.

6.2 All bevels shall be cleaned by COMPANY approved methods, and CONTRACTOR shallfurnish labor, equipment and materials to cut and rebevel defective or damaged bevelsdiscovered prior to, or during, line-up.

6.3 CONTRACTOR shall mark each pipe joint with unique numbers, when added to the tie-in or field-fit spool. Numbers shall be painted clearly on both sides of the pipeline outer


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coating adjacent to the field joint at one end of the pipe, using COMPANY approved paint.

6.4 CONTRACTOR shall maintain a record of each pipe joint, elbow or fitting or partthereof, incorporated into a tie-in or field-fit spool, and shall submit this record toCOMPANY, with the following information:

Pipe joint / elbow / fitting identification number Pipe joint / elbow / fitting heat number Pipe joint / elbow / fitting lengthCumulative lengthWeld number Time and date the pipe joint / elbow / fitting is added on and welded

NDE results

Weld repairsWeld cutouts with amended pipe joint length recordsConcrete weight-coating thickness (if applicable)

Tie-in or field-fit spool record shall also include weld inspection and weld radiographyresults corresponding to pipe joint / elbow / fitting welding sequences. Record formatand documentation procedures, shall be approved by COMPANY prior to mobilization.

6.5 CONTRACTOR shall not release external line-up clamps until both root bead and hot pass have been completed.

6.6 CONTRACTOR shall perform pipeline welding in strict accordance with Specificationfor Pipeline Welding, Specification 8791/09-WS1.

6.7 CONTRACTOR shall perform pipeline welding radiography and other non-destructiveexamination (N.D.E.) methods in strict accordance with Specification for WeldRadiography / N.D.E, Specification 8791/09-WS2.

6.8 CONTRACTOR shall repair all damaged factory applied coatings in accordance with theSpecification for Pipeline Anti-Corrosion Coatings, 8791/09-LP3, and the Specificationfor Concrete Weight Coating, 8791/09-LP5. Spool field joints shall be coated usingRaychem HTLP 60 heat-shrink sleeves or COMPANY-approved equivalent. Applicationof the heat-shrink sleeves shall be in accordance with manufacturers recommendations.

6.9 CONTRACTOR shall hydrotest each spool to 17.2 MPa for a hold period of 24 hours.COMPANY shall witness and approve the hydrotest before the spool can be installed.


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7. SPOOL INSTALLATION

CONTRACTOR shall clear all debris, natural or otherwise, which will interfere with pipeline spool installation, prior to installation. Pipeline tie-ins and field-fit spools shall be installed in accordance with COMPANY approved procedures.

7.1 CONTRACTOR shall lower spools to the seabed alongside, not over, existing seabedfacilities.

7.2 CONTRACTOR shall provide temporary protection over the flange faces which shallonly be removed immediately prior to final alignment and flange mating. Any damage toflange faces must be immediately reported to COMPANY.

7.3 CONTRACTOR shall install subsea flanges in accordance with COMPANY-approved procedures and as set forth below:

Remove burrs or other foreign particles from flange facing, boltholes, and studs.Using drift pins to align flanges, insert one stud at bottom center and one 90 degreeseach side of bottom center. Carefully insert the gasket to ensure no damage occurs.Insert three studs 120 degrees apart, assemble nuts on these three studs and handtighten to align the flanges. Insert remaining studs and nuts and hand tighten.Complete make-up of the flange using a "Hydratite" or similar, COMPANY-approved hydraulic stud tensioner.Stud tensions and tensioning sequence shall be approved by COMPANY.

7.4 CONTRACTOR shall first attach the structure/spool flange to allow for minor errors inspool dimensions being accommodated by adjustments in the pipeline position whenmaking the pipeline/spool connection.

7.5 CONTRACTOR shall not use excessive force when making the final connection. If, inthe opinion of COMPANY, excessive force is required, CONTRACTOR shall retrievethe spool to the surface and adjust its dimensions in accordance with new metrology data.

7.6 Spoolpiece protection shall be installed in accordance with good industry practices,COMPANY-approved procedures and Contract Drawings.

8. SURVEY

CONTRACTOR shall perform surveys of the spoolpieces before and after spool protection installation shall also encompass the structure and the pipelines for 100 meterseach side of each spool.

The surveys may be made either with diver cameras or using an ROV.


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9. RECORDS

CONTRACTOR shall provide for COMPANY approval, as-built records which shallinclude as a minimum:

As-built drawings of the structuresAs-built drawings of the spoolpiecesAs-built videoMaterials certificatesInspection and test reportsWeld NDT recordsWeld radiographic recordsWelder qualification recordsPile driving records

Stud tensioning recordsSpool material records in accordance with Section 6.3

Documents

Specification for Subsea Structure and Spool Installation Ps4