Methods Statement-cold Work

COLD WORK METHOD Assumption:
Shutdown Operation
Pipeline De-Gassing to be done
Low level construction HSE
Inshore Replacement Location
4.5m minimum offset / parallel distance (depend on trench width and soil shear strength)

Pre-Lay Survey

Mob. Personnel & Equipments

Onshore Site Preparation - Fabrication Pipe Ramp Launcher - Fabrication new U-Spool (welding) - Fabrication west/east gooseneck (optional to be fabricated onshore/offshore) - Fab. end flange for new spool & gooseneck (optional) - Hydrotest on fabricated new U-Spool (option) Transportation to Offshore - West/East Gooseneck (optional to be fabricated on derrick barge) - Material for Tie-In Spool (west/east) - A-Frame (if any offshore lifting required for tie-in)

Launching new U-Spool - Install floaters & wire on new U-Spool - Install stability guide on new U-Spool - Side-boom/Backhoe required

Offshore Site Preparation - New Trench preparation (backhoe dredger, swamp backhoe, etc) - Installation Cofferdam (west/east point) – using sheet pile / sand bags, etc (optional) - Develops access channel for new U-Spool (TBA during Pre-Lay Survey)

Coordinated Pipeline Depressurized/shutdown

To be coordinated with all construction preparation

Pipeline De-Gassing / N2 Purging Towing to offshore

Offshore Fabrication - Welding West/East Gooseneck to new U-Spool (optional using Flange)

Floaters installation on OLD U-Spool

Using WELDING/Flange Using WELDING/Flange

Cutting Process - West/East Point for future tie-in on the existing mainline/OLD U-Spool

TIE-IN (west point) – Lift & Lower

TIE-IN (west point) – Cofferdam - Lowering new U-Spool in new Trench - 1st Metrology and Fit-up new U-Spool end to west/east point - Welding west point (tie-in spool will be required) inside Cofferdam - Connecting Flange (optional tie-in)

Alternative using WELDING

- Lifting on WEST line & new U-Spool end (west side) – check integrity - 1st Metrology and Fit-up - Welding west point (tie-in spool will be required) - Lowering (mainline & new U-Spool) west side - Connecting Flange (optional tie-in)

Remove OLD U-Spool

In case tie-in using Flange is applied, lifting and lowering works to be minimized.

TIE-IN (east point) – Cofferdam

TIE-IN (east point) – Lift & Lower

nd

- 2 Metrology and Fit-up new U-Spool end to east point only - Welding east point (tie-in spool will be required) inside Cofferdam - Connecting Flange (optional tie-in)

Alternative using WELDING

- Lifting on EAST line & new U-Spool (east side) – check integrity - 2nd Metrology and Fit-up - Welding east point (tie-in spool will be required) - Lowering (mainline & new U-Spool) east side - Connecting Flange (optional tie-in)

Using MECHANICAL CONNECTOR TIE-IN (west point)

Installation of Marking Piles for new U-Spool

- Deploy griplock connector and stabbed onto the west line - 1st Metrology at west point - Fabrication tie-in spool complete with Flangemate adjuster on Board - Fit-up & Bolted

Pre-Commissioning

TIE-IN (east point) - Deploy griplock connector and stabbed onto the east line - 2nd Metrology at east point - Fabrication tie-in spool complete with Flangemate adjuster on Board - Fit-up & Bolted

Required special equipment for underwater BT installation

Installation of Protection Covers - sand bags - concrete mattress (option) - rock dump (option)

Demob of personnel/equipment (except for as built survey)

As Built Survey

Alternative process if Tie-In using Mechanical Protector is applied.

Drag / Lift the OLD U-Spool using AHT/Derrick Barge (TBA)