Chim Sao Field Development

  • January 23, 2017
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COMPANY: EMAS-AMC

PROJECT TITLE: Chim Sao Field Development

CLIENT: Premier Oil Vietnam

LOCATION: Vietnam

YEAR: 2014

VESSEL: Diving Support Vessel (DSV) Toisa Paladin

SCOPE OF WORK:

This document describes the 4 x 10” spools installation procedure at PLEM 3 and TPAM ends that will be applied including all preparatory works that need to be performed by all parties involved in operations. Installation of the 10” spools will be carried out by the DSV Toisa Paladin during Phase 3 of the DUA Subsea Development Project.

MY INVOLVEMENT:

I develop the procedure and executed the spool installation offshore

INTRODUCTION

Premier Oil Vietnam Offshore (POVO) is the operator of the Chim Sao field in Block 12W Offshore Vietnam. The Chim Sao field is located in the Nam Con Son Basin approximately 400km south east of Ho Chi Minh City. The existing Chim Sao development comprises the Lewek Emas FPSO host facility in approximately 94m seawater with a WHP to the South West in approximately 95m water depth, the WHP being minimal facilities and controlled from the Lewek Emas FPSO. Infield flowlines transfer produced fluids from the WHP to the FPSO, and utilities (water for water injection, gas for gas lift and controls umbilical) from the FPSO to the WHP.

POVO intends to develop the Dua subsea field as a subsea tieback to the Lewek Emas FPSO. The Dua development comprises a 17km subsea tieback of 3 wells with dual 10” flowlines, with the production flowline requiring thermal insulation to minimise the volume of waxing tendency of the crude and the criteria adopted to mitigate wax build up. The second (uninsulated) pigging/gas lift flowline is provided to allow round trip pigging and also for gas lift capacility.

POVO has awarded the EPCI of Dua development to PTSC and PTSC has in turn awarded the T&I scope to EMAS AMC.

The Dua Subsea Development Project is integrated into the Block12W infrastructure and is shown schematically in Figure 1-1.

Installation Data

TPAM (Twin Pipeline Active Manifold) and PLEM

Two 10” spools will be tied in to PLEM 3 that will be within 250m radius from the FPSO turret nominal centreline and two 10” spools will be tied in to the TPAM, which will be approximately 17 km away from the FPSO turret. The proposed coordinates for the centreline of PLEM3 and TPAM are defined in Table 4.1.1.

Object Easting (m) Northing (m) Heading (º from N)
PLEM 203,442.00 812,840.00 60.1
TPAM 214,746.77 824,995.43 45.0

10” Spools at PLEM 3

  Production Pipeline Pigging/ Gas Lift Pipeline
Water Depth 93.2m LAT
Spool Dia. and wall thickness 273.1mm OD. X 15.9mm WT (seamless linepipe)

273.1mm OD. X 18.3mm WT (bend)
Anti-Corrosion Coating 35.3mm insulation coating on straights

26mm SPU coatings on bends

 2.5mm 3LPE coating
Concrete Weight Coating N.A.
Steel Material API 5L Grade X65 (SMYS @ T≤50º =448MPa)
Max. Design Length 64.1m 66.9m
Bend 90 deg. 5D bend x 1ea

79.46 deg. 5D bend x 1 ea

30 deg. 5D bend x 2 ea

 90 deg. 5D bend x 1ea

70.87 deg. 5D bend x 1 ea

30 deg. 5D bend x 2 ea
Flange 10” swivel ASME B16.5 Class 1500# 241.3mm dia. bore (to pipeline)

10” swivel ASME B16.5 Class 1500# 236.5mm dia. bore (to PLEM 3)
Bolt/ Nut 1-7/8” x 610mm lg. studbolts A320M L7M c/w 2 nuts
Gasket R54 Octagonal gasket drilled to prevent hydrolock- ANSI B16.20
Air Weight (Empty) 9.1 T 7.7 MT
Submerged weight (Free Flooded) 7.9 MT 6.7 MT
Section 1 1
Anode N.A.

 

Spool Installation Sequence

4 nos. of 10” spools will be installed as per Table 7.2.1.

Sequence Spool No Description
#1 Spool #1 10’’ Production Pipeline Spool @ PLEM 3
#2 Spool #2 10’’ Pigging/Gas Lift Pipeline Spool @ PLEM 3
#3 Spool #3 10’’ Production Pipeline Spool @ TPAM
#4 Spool #4 10’’ Pigging/Gas Lift Pipeline Spool @ TPAM

FIELD  & TRANSPORTATION

 

LOADOUT & TRANSPORTATION

General

The 10” spools will be fabricated by PTSC in Vung Tau, Vietnam. Upon completion of fabrication, field joint coating and NDT, the 10” spools will be loaded onto 250’ cargo barge in PTSC Jetty, Vung Tau. Load out and tie-down of the 10” spools will be done by PTSC. Lifting rigging will be pre-rigged during load out. Voyage summary is presented in Table 5.1.1.

Voyage Barge Ocean Tug Main Cargo
1 “Maritime Swift”1

(250 ft x 80 ft)

 

 “Ocean Union” 1

(65T Bollard Pull)

 

 1) 10” tie-in spools x 4 ea.

Cargo weight is approx. 40MT

 

Table 5.1.1: Voyage Summary

Notes:

  1. Barge and tug have not been confirmed. Actual barge and tug will be updated after confirmation of barge and tugs charter party.
  2. Material barge layout and seafastening for the spools are covered in Ref. /41./

Transportation & Seafastening Configuration

The material barge detailed ballasting condition (to be ballasted to 2m freeboard) and seafastening of the spools transportation barge will be performed in accordance with Ref. /46./. Details of the transportation is presented in Ref. /41./. For spools transportation and seafastening drawings, refer to drawing no. 12012-AMC-DUA-ME-DW-1910.

SPOOL INSTALLATION AIDS

This section details the major equipment and installation aids required for the spools installation. They are listed in Table 6.4.1.

FIM
Item Description Qty1 Remarks
1 10” tie-in spool 4 Fabricated, field joint coated and NDT by PTSC. Loadout on 250’ cargo barge
2 1-7/8” x 610mm lg. stud bolts 96 Loadout on 250’ cargo barge
3 R54 Octagonal gasket 8 Loadout on 250’ cargo barge
Equipment and Installation Aids
Item Description Qty1 Remarks
1 Yokohama Fenders (3.3m x 6.5m) 4  
2 Mooring rope 1 lot  
3 Cutting torch 1 set  
4 Diver’s A-frame 2  
5 Diver’s working basket 1  
6 Broco 1 set  
7 Hydratight 1 set  
8 Fishing rope 1 lg  
9 AF 2-15/16 flogging spanner 2 For spool installation
10 Diver subsea tool box 1  
11 Nut splitter (size TBC) TBC  
12 Spreader Bar 1 lgth  
13 0.5MT air bags    
14 10MT clump weight    
Lift Rigging for Spreader Bar

(Refer to 12012-AMC-DUA-ME-DW-2030” Spreader Bar & Rigging Detail (From Crane Hook to Spreader Bar)”
       
Lift Rigging for 10” Production Pipeline Spool No. 1 at PLEM 3

(Refer to 12012-AMC-DUA-ME-DW-2034 10” Production Pipeline Spool No. 1 at PLEM 3 Lift Rigging Arrangement)
1 Wire Rope Sling – 1 (26mm dia., 5.73m long) 1 Pre-rigged to spool by PTSC
2 Wire Rope Sling – 2 (26mm, 5.74m long) 1
3 Wire Rope Sling – 3 (26mm, 6.11m long) 1
4 Wire Rope Sling – 4 (26mm, 7.75m long) 1
5 Wire Rope Sling – 5 (26mm, 5.04m long) 1
6 Wire Rope Sling – 6 (26mm, 6.39m long) 1
7 Shackle Crosby G-2130 (SWL 17 MT) 3
8 Master Link ‘A-342 Alloy’ (SWL 16.43 MT) 3
9 Shackle Crosby G-2130 (SWL 8.5 MT) 7
10 Round Sling (To double choke around spool, 3m long) 6
11 Chain Block ‘Maxi Lift MC-10’ (1m long) 5
Lift Rigging for 10” Pigging/Gas Lift Spool No. 2 at PLEM 3

(Refer to 12012-AMC-DUA-ME-DW-2035 10” Pigging/Gas Lift Spool No. 2 at PLEM 3 Lift Rigging Arrangement)
1 Wire Rope Sling – 1 (26mm dia., 5.12m long) 1  

 

 

 

Pre-rigged to spool by PTSC

 

 
2 Wire Rope Sling – 2 (26mm, 5.38m long) 1
3 Wire Rope Sling – 3 (26mm, 9.88m long) 1
4 Wire Rope Sling – 4 (26mm, 4.14m long) 1
5 Wire Rope Sling – 5 (26mm, 7.38m long) 1
6 Wire Rope Sling – 6 (26mm, 4.48m long) 1
7 Wire Rope Sling – 7 (26mm, 8.27m long) 1
8 Shackle Crosby G-2130 (SWL 17 MT) 3
9 Master Link ‘A-342 Alloy’ (SWL 16.43 MT) 3
10 Shackle Crosby G-2130 (SWL 8.5 MT) 8
11 Round Sling (To double choke around spool, 3m long) 7
12 Chain Block ‘Maxi Lift MC-10’ (1m long) 6
Lift Rigging for 10” Production Pipeline Spool No. 3 at TPAM

(Refer to 12012-AMC-DUA-ME-DW-2036 10” Production Pipeline Spool No. 3 at TPAM Lift Rigging Arrangement)
1 Wire Rope Sling – 1 (26mm dia., 6.56m long) 1 Pre-rigged to spool by PTSC

 
2 Wire Rope Sling – 2 (26mm, 5.50m long) 1
3 Wire Rope Sling – 3 (26mm, 9.14m long) 1
4 Wire Rope Sling – 4 (26mm, 4.63m long) 1
5 Wire Rope Sling – 5 (26mm, 6.72m long) 1
6 Wire Rope Sling – 6 (26mm, 5.98m long) 1
7 Wire Rope Sling – 7 (26mm, 7.31m long) 1
8 Shackle Crosby G-2130 (SWL 17 MT) 3
9 Master Link ‘A-342 Alloy’ (SWL 16.43 MT) 3
10 Shackle Crosby G-2130 (SWL 8.5 MT) 8
11 Round Sling (To double choke around spool, 3m long) 7
12 Chain Block ‘Maxi Lift MC-10’ (1m long) 6
Lift Rigging for 10” Pigging/Gas Lift Spool No. 4 at TPAM

(Refer to 12012-AMC-DUA-ME-DW-2037 10” Pigging/Gas Lift Spool No. 4 at TPAM Lift Rigging Arrangement)
1 Wire Rope Sling – 1 (26mm dia., 6.60m long) 1  

 

 

 

 

Pre-rigged to spool by PTSC

 

 

 

 

 

 
2 Wire Rope Sling – 2 (26mm, 5.59m long) 1
3 Wire Rope Sling – 3 (26mm, 6.77m long) 1
4 Wire Rope Sling – 4 (26mm, 8.32m long) 1
5 Wire Rope Sling – 5 (26mm, 6.05m long) 1
6 Wire Rope Sling – 6 (26mm, 5.20m long) 1
8 Shackle Crosby G-2130 (SWL 17 MT) 3
9 Master Link ‘A-342 Alloy’ (SWL 16.43 MT) 3
10 Shackle Crosby G-2130 (SWL 8.5 MT) 7
11 Round Sling (To double choke around spool, 3m long) 6
12 Chain Block ‘Maxi Lift MC-10’ (1m long) 5
Lifting Rigging for A-frame

(Refer to 12012-AMC-DUA-ME-DW-####  A-Frame Lifting Rigging Arrangement)
1 TBC –  
Crane Main Block Stinger

(Refer to FSTM-TP-DRN-00005 Crane Main Block Standard Rigging)
1 Gunnebo M-3226-10 Master Link 43MT SWL 2  
2 Green Pin Bolt Type Safety Anchor Shackle 85MT SWL 1  
Crane Aux Block Stinger
1 TBC –  

WEATHER CRITERIA

A general guideline for the installation environment is shown in Table 7.1.1 below /45./.

10in Tie-in Spool Installation
Hs/Heading 0 15 165 180 195 345
<1.5            
1.5 to 2.0            
2.0 to 2.5            
>2.5            

 

  Installation can continue

 

  Installation can continue after discussion and agreement between OCM (offshore construction manager) and CSR (client’s representative)

 

  Operation must not start

 

The wave heading orientations are in reference to the diagram below:

Figure 7.1: Orientation of wave headings with respect to Toisa Paladin

For the wave height criteria shown above, the corresponding heave motions can be referred to in Ref. /28./ and /45./. For the wave height not stated, linear interpolation can be applied to obtain the corresponding heave motion. It is noted that the Hs reported above is indicative.

SPOOL INSTALLATION

Spool #1 & Spool #2 Installation at PLEM3 Location

Task Summary

Carry out the following activities:

  • Alongside spool barge
  • Lift spool from cargo barge
  • Lower spools into water
  • Remove 2 blind flanges @ PLEM 3 and 2 blind flanges @ pipelines
  • Insert chemical bundle and tie-in spool @ PLEM 3 & Pipelines (Production & Pigging/Gas Lift)

Operational limitations

Hs is equal or less than 2.0m

Maximum window for installation is 24 Hours

Status

  • Project brief completed.
  • Toolbox talk has been conducted with all personnel involved in the operation.
  • Completed general deck preparations for lift, i.e. function check on equipment, diver’s work basket material check, mooring rope in standby position, yokohama buoys have been installed and etc.
  • Perform communication check prior to operation commencing including but not limited to: FPSO, bridge, shift supervisor, deck foreman / barge foreman, crane operator.
  • All survey data is displayed on vessel navigation screen.
  • FPSO is on heading control.
  • Toisa Paladin has been set up on location as planned.
  • PTW in place.
  • Weather Forecast has been assessed for installation window.
  • Pipeline is flooded.
  • Inform FPSO entering 500m zone in advance.
  • Over boarding chute has been removed
  • Crane has been set in AHC mode

Pre-Installation Works & Spool Deployment

  • Once DSV is outside of 500m zone, master to inform material barge tow tug that DSV will along side the material barge. Ocean Union tug (tow tug) to maintain material barge position and heading
    DSV to move in DP and alongside material barge on the STBD side in bow to stern configuration and secure material barge. Refer to drawing no: 12012-AMC-DUA-ME-DW-2044-01. Refer to /47./ for cargo barge mooring procedure.
  • Transfer riggers, field engineers, MWS, fitters and surveyors to material barge. Refer to /48./ for Personnel Transfer Procedure. SAFETY NOTE: Work vest to be worn for personnel transfer
  • Inspect spool for the following:1) Spool lift rigging – Refer drawing no. 12012-AMC-DUA-ME-DW-20342) Spool Seafastening – Refer drawing no. 12012-AMC-DUA-ME-DW-19103) Check spool condition for any damagesWhile inspecting, deploy ROV to conduct seabed survey between PLEM 3 and pipelines.
  • Surveyor to install beacons at the back of flanges and switch on the beacon.
  • Remove deck seafastening of spool. Riggers to install running tag lines on the spool as necessary and remove the rope protector.
  • Position the crane block above spreader bar and connect the spreader bar lift rigging to crane block.
  • Pick up spreader bar and connect the spreader bar to the pre-rigged slings at the spool.Refer to drawing nos.:12012-AMC-DUA-ME-DW-203412012-AMC-DUA-ME-DW-2046
  • Position crane block above spool COG and apply tension to the sling.
  • Pick-up the spool slowly until the spool is clear of the seafastening. Spool orientation as per final orientation will be done by ROV or diver. SAFETY NOTE: Spool may swing. Riggers will have to keep the running tags lines tight. Running tag line can be wrapped around DSV bulwark to prevent movement.
  • Unmoor the material barge and cast off the barge. Refer to drawing no. 12012-AMC-DUA-ME-DW-2044-02. Note: Personnel on material barge will be transferred back to DSV at later stage
  • Launch ROV to monitor the lowering of the spool.
    Pay out the crane wire slowly until the splash zone and free flood the spool. Once the spool is lowered under water, running tag lines will be released. Continue to lower spool until 10m above the seabed.
  • DSV to request permission from FPSO before entering 500m zone.
  • After permission has been granted, start set-up. Move DSV to set-up location with the spool hanging at STBD side of DSV while ROV to monitor the spool.Refer to drawing no.: 12012-AMC-DUA-ME-DW-2044-03 12012-AMC-DUA-ME-DW-2044-04

Production Pipeline Tie-In @ PLEM End

  • Launch SAT divers and deploy diver’s work basket.
  • Diver to swim to PLEM 3.
  • Diver to open the diffuser installed at the blind flange @ PLEM 3 flange to check for pressure in the subsea structure. Diver to remove the blind flange by nut splitter (size TBC).
  • Diver to instruct the crane to bring the spool nearer to flange face until the alignment of bolt holes of the PLEM 3 and tie-in spool flange are in good position for bolt insertion.
  • Diver to install the flange pulling device (3 MT) comealong at 3 & 9 o’clock bolt holes and reaction force jig at PLEM 3 flange.
  • Bring the spool flange face close to PLEM 3 using the combination of crane movement and flange pull-in device, as well as the chain block installed on to spool, to adjust the elevation.
  • Diver to place and align the bolt holes by using drift pins, then to insert bolts to any of the lower flange holes, where available. Bolts insertion for lower half of the flange will continue until flange connection is loosely secured.
  • When the lower half of bolts and nuts are loosely secured, diver to remove drift pins.
  • Using fishing rope, diver to insert the gasket into the flange groove. Diver to also insert chemical bundle (Quantity: TBC). Refer to Appendix C for MSDS.
  • Diver to continue to insert upper half bolts and hand tighten up all the nuts. Meanwhile, carefully check to ensure the ring gasket is in proper position.
  • When all of the bolts & nuts are installed and hand tightened in position, diver to proceed to hydraulic bolt tensioning operation. Refer Appendix E for bolt tensioning procedure/data sheet.
  • Diver to disconnect spool lift rigging at spool except wire sling no.3, no.4 & no.5 which are to be used to tie in the spool and the pipeline side at later stage. Refer to drawing no. 12012-AMC-DUA-ME-DW-2043-01
  • Recover crane to deck with the spreader bar.

Production Pipeline Tie-In @ Pipeline End

  • Diver to come back to bell and DSV to reposition closer to 10’’ production pipeline end.
  •  Diver to swim to production pipeline end and install the handling rigging (Size: TBC) at approx. 10m from flange face at pipelines side. On the deck of DSV, riggers to rig up 1 x 10T diver’s A-frame c/w 5T x 3.5 m chain block and 2 taglines opposite from each other. The weight of the A-frame is approx. 1.0 MT each
  • Crane to pick up the A-frame by crane and slew to STBD side. Lower the frame into the water slowly.
  • Diver to move in and guide the frame to location when it is approx. 3 m from seabed over the production pipeline. Note: Attention to be paid to umbilical management whilst guiding / lowering A-frame by diver. Diver to confirm A-frame is in position, stable and horizontal by eye sight. Crane to slack and diver to release the crane hook. Deck to recover crane hook.
  • Diver to connect the chain block to the handling rigging.
  • Diver to pull-in the chain block to lift up the production pipeline from seabed.
  • Diver to release the residual hydro test pressure inside the pipeline through the diffuser installed at the blind flange. After the pressure has been released, diver to remove the blind flange by nut splitter (Size: TBC).
  • Diver to connect crane to the spool with the crane stinger. Refer to drawing no. 12012-AMC-DUA-ME-DW-2043-01
  • Diver to instruct the crane to bring the spool nearer to flange face until the alignment of bolt holes of the tie-in spool flange and pipeline flange are in good position for bolt insertion. Pre-installed air bags may be used to facilitate the alignment.
  • Diver to install the flange pulling device (3 MT) comealong at 3 & 9 o’clock bolt hole and reaction force jig at pipeline flange.
  • Bring the spool flange face close to pipeline using the combination of crane movement and flange pull-in device, as well as A-Frame installed to pipeline to adjust the elevation.
  • Diver to place and align the bolt holes by drift pins, then insert bolts to any lower flange holes, where available. Bolts insertion for lower half of the flange will continue until flange connection is loosely secured.
  • When lower half of bolts and nuts are loosed secured, diver to remove drift pin.
  • Using fishing rope, diver to insert the gasket into the flange groove. Diver also to insert chemical bundle. (Quantity: TBC). Refer to Appendix C for MSDS.
  • Diver to continue to insert upper half bolts and hand tighten up all the nuts. Meanwhile, carefully check to ensure the ring gasket is in proper position.
  • When all of the bolts & nuts are installed and hand tightened in position, diver to proceed to hydraulic bolt tensioning operation. Refer Appendix E for bolt tensioning procedure/data sheet.
  • De-rig the lift rigging from the spool and recover the rigging to the deck.
  • Remove the beacon on the spool and recover the diver to diving bell. Ensure there is no obstruction/ debris at production pipeline tie-in spool location.

Pigging/Gas Lift Pipeline Tie-In  Installation @ PLEM 3 Location

  • Upon completion of 10’’ production tie-in spool, DSV to move out of the 500M zone to receive the spool barge in bow to stern configuration and secured. Refer to drawing nos.: 12012-AMC-DUA-ME-DW-2044-01
  • Repeat steps 2 to 12 in sub-task #1.1 & all steps in sub-task #1.2 for 10’’ pigging/gas lift tie-in @ PLEM end. Refer to drawings nos.: 12012-AMC-DUA-ME-DW-2044-02; 12012-AMC-DUA-ME-DW-2044-03; 12012-AMC-DUA-ME-DW-2044-04; 12012-AMC-DUA-ME-DW-2035; 12012-AMC-DUA-ME-DW-2047
  • Repeat all the steps in sub-task #1.3 for 10’’ pigging/gas lift tie-in @ Pipeline end. Refer to drawings nos.: 12012-AMC-DUA-ME-DW-2043-02
  • Launch ROV to perform as-built and debris survey on both tie-in spools @ PLEM 3
  • Take fixes at following spots for surveyor to draw the as-built of the spools:
    a) Flange connections
    b)    Start of bend
    c)     End of bend
  • Recover the ROV once surveyor does not require additional data.
  • Upon completion, DSV to move to TPAM location.

Spool #3 & Spool #4 Installation at TPAM Location

Task Summary

Carry out the following activities:

  • Alongside spool barge
  • Lift spool from cargo barge
  • Lower spools into water
  • Remove 2 blind flanges @ TPAM and 2 blind flanges @ pipelines
  • Insert chemical bundle and tie-in spool @ TPAM & Pipeline (Production & Pigging/Gas Lift)

Status

  • Project brief completed.
  • Toolbox talk has been conducted with all personnel involved in the operation.
  • Completed general deck preparations for lift, i.e. function check on equipment, diver’s work basket material check, mooring rope in standby position, yokohama buoys have been installed and etc.
  • Perform communication check prior to operation commencing including but not limited to: bridge, shift supervisor, deck foreman / barge foreman, crane operator.
  • All survey data is displayed on vessel navigation screen.
  • Toisa Paladin has been set up on location as planned.
  • PTW in place.
  • Weather Forecast has been assessed for installation window.
  • Pipeline is flooded.
  • Over boarding chute has been removed
  • Crane has been set in AHC mode

Pre-Installation Works & Spool Deployment

  • Set-up DSV and master to inform material barge tow tug that DSV will along side the material barge. Ocean Union tug (tow tug) to maintain material barge position and heading. DSV to move in DP and alongside material barge on the STBD side in bow to stern configuration and secure material barge. Refer to drawing no: 12012-AMC-DUA-ME-DW-2045-01. Refer to /47./ for cargo barge mooring procedure.
  • Transfer riggers, field engineers, MWS, fitters and surveyors to material barge. Refer to /48./ for Personnel Transfer Procedure. SAFETY NOTE: Work vest to be worn for personnel transfer.
  • Inspect spool for the following:
    1) Spool lift rigging – Refer drawing no. 12012-AMC-DUA-ME-DW-20362) Spool Sea fastening- Refer drawing no. 12012-AMC-DUA-ME-DW-19103) Spool condition; any damagesWhile inspecting, deploy ROV to conduct seabed survey between the TPAM and pipelines.
  • Surveyor to install beacons at the back of flanges and switch on the beacon.
  • Remove deck seafastening at spool. Riggers to install running tag lines on the spool, as necessary, and remove the rope protector.
  • Position the crane block above spreader bar and connect the spreader bar lift rigging to crane block.
  • Pick up spreader bar and connect the spreader bar to the pre-rigged slings at the spool.Refer to drawing nos.:12012-AMC-DUA-ME-DW-203612012-AMC-DUA-ME-DW-2048
  • Position crane block above spool COG and apply tension to the sling.
  • Pick-up the spool slowly until the spool is clear of the seafastening. Spool orientation as per final orientation will be done by ROV or diver. SAFETY NOTE: Spool may swing. Riggers will have to keep the running tags lines tight. Running tag line can be wrapped around DSV bulwark to prevent movement.
  • Unmoor the material barge and cast off the barge. Refer to drawing no. 12012-AMC-DUA-ME-DW-2045-02. Note: Personnel on material barge will be transferred back to DSV at later stage
  • Launch ROV to monitor the lowering of the spool.Pay out the crane wire slowly until the splash zone and free flood the spool. Once the spool is lowered under water, running tag lines will be released. Continue to lower spool until 10m above the seabed.
  • Move DSV to set-up location with the spool hanging at STBD side of DSV while ROV to monitor the spool.Refer to drawing no.:12012-AMC-DUA-ME-DW-2045-03

    12012-AMC-DUA-ME-DW-2045-04

Production Pipeline Tie-In @ TPAM End

  • Launch SAT divers and deploy diver’s work basket.
  • Diver to swim to TPAM.
  • Diver to open the diffuser installed at TPAM blind flange to check for pressure in subsea structure. Diver to remove the blind flange by nut splitter (size TBC).
  • Diver to instruct the crane to bring the spool nearer to flange face until the alignment of bolt holes of the TPAM and tie-in spool flange are in good position for bolt insertion.
  • Diver to install the flange pulling device (3 MT) comealong at 3 & 9 o’clock bolt holes and reaction force jig at TPAM flange.
  • Bring the spool flange face close to TPAM using the combination of crane movement and flange pull-in device, as well as the chain block installed on to spool, to adjust the elevation.
  • Diver to place and align the bolt holes by using drift pins, then to insert bolts to any of the lower flange holes, where available. Bolts insertion for lower half of the flange will continue until flange connection is loosely secured.
  • When the lower half of bolts and nuts are loosely secured, diver to remove drift pins.
  • Using fishing rope, diver to insert the gasket into the flange groove. Diver to also insert chemical bundle (Quantity: TBC). Refer to Appendix C for MSDS.
  • Diver to continue to insert upper half bolts and hand tighten up all the nuts. Meanwhile, carefully check to ensure the ring gasket is in proper position.
  • When all of the bolts & nuts are installed and hand tightened in position, diver to proceed to hydraulic bolt tensioning operation. Refer Appendix E for bolt tensioning procedure/data sheet.
  • Diver to disconnect spool lift rigging at spool except wire sling no.5, no.6 & no.7 which are to be used to tie in the spool and the pipeline side at later stage. Refer to drawing no. 12012-AMC-DUA-ME-DW-2050-01
  • Recover crane to deck with the spreader bar.

Production Pipeline Tie-In @ Pipeline End

  • Diver to come back to bell and reposition DSV closer to 10’’ production pipeline end.
  • Diver to swim to production pipeline end and install the handling rigging (size: TBC) at approx. 10m from flange face at pipelines side. On the deck of DSV, riggers to rig up 1 x 10T diver’s A-frame c/w 5T x 3.5 m chain block and 2 taglines opposite from each other. The weight of the A-frame is approx. 1.0 MT each.
  • Crane to pick up the A-frame by crane and slew to STBD side. Lower the frame into the water slowly.
  • Diver to move in and guide the frame to location when it is approx. 3 m above seabed over the production pipeline. Note: Attention to be paid to umbilical management whilst guiding / lowering A-frame by diver. Diver to confirm A-frame is in position, stable and horizontal by eye sight. Crane to slack and diver to release the crane hook. Deck to recover crane hook.
  • Diver to connect the chain block to the handling rigging.
  • Diver to pull-in the chain block to lift up the production pipeline from seabed.
  • Diver to release the residual hydrotest pressure inside the pipeline through the diffuser installed at the blind flange. After the pressure has been released, diver to remove the blind flange by nut splitter (size TBC).
  • Diver to connect crane to the spool with the crane stinger. Refer to drawing no. 12012-AMC-DUA-ME-DW-2050-01
  • Diver to instruct the crane to bring the spool nearer to flange face until the alignment of bolt holes  of the tie-in spool flange are in good position for bolt insertion. Pre-installed air bags may be used to facilitate the alignment.
  • Diver to install the flange pulling device (3 MT) comealong at 3 & 9 o’clock bolth hole and reaction force jig at pipeline flange.
  • Bring the spool flange face close to pipeline using the combination of crane movement and flange pull-in device as well as A-Frame installed to pipeline to adjust the elevation.
  • Diver to place and align the bolt holes by drift pins, then to insert bolts to any lower flange holes, where available. Bolts insertion for lower half of the flange will continue until flange connection is loosely secured.
  • When lower half of bolts and nuts are loosed secured, diver to remove drift pins.
  • Using fishing rope, diver to insert the gasket into the flange groove. Diver to also insert chemical bundle (Quantity: TBC). Refer to Appendix C for MSDS.
  • Diver to continue to insert upper half bolts and hand tighten up all the nuts. Meanwhile, carefully check to ensure the ring gasket is in proper position.
  • When all of the bolts & nuts are installed and hand tightened in position, diver to proceed to hydraulic bolt tensioning operation. Refer Appendix E for bolt tensioning procedure/data sheet.
  • De-rig the lift rigging from the spool and recover the rigging to the deck.
  • Remove the beacon on the spool and recover the diver to diving bell. Ensure there are no obstruction/ debris at production pipeline tie-in spool location.

Pigging/Gas Lift Pipeline Tie-In Spool Installation @ TPAM

  • Upon completion of 10’’ production tie-in spool, DSV to move out of the subsea assets to receive the spool barge in bow to stern configuration and secured. Refer to drawing nos.: 12012-AMC-DUA-ME-DW-2045-01
  • Repeat steps 2 to 11 in sub-task #2.1 & all steps in sub-task #2.2 for 10’’ pigging/gas lift tie-in @ TPAM end.Refer to drawing nos.:12012-AMC-DUA-ME-DW-2045-02

    12012-AMC-DUA-ME-DW-2045-03

    12012-AMC-DUA-ME-DW-2045-04

    12012-AMC-DUA-ME-DW-2037

    12012-AMC-DUA-ME-DW-2049

  • Repeat all the steps in sub-task #2.3 for 10’’ pigging/gas lift tie-in @ Pipeline end.Refer to drawing nos.:

    12012-AMC-DUA-ME-DW-2050-02

  • Take fixes at following spots for surveyor to draw the as-built of the spools:a)     Flange connections

    b)    Start of bend

    c)     End of bend

    Recover the ROV once the surveyor does not require additional data.

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