• Australia
  • Oceania
  • Asia-Pacific
Case Study

6 inch Flexible lay

FPSO to platform umbilical installation

Shelf Subsea were selected to perform the laying of a 6” flexible riser from a moored FSO to unmanned platform during the monsoon Season in the South China Sea.  The work involved laying from platform side through the bell tube, hand over to messenger wire and pull into platform.  Then continuing the lay to FSO side where a complex process of tying the riser into a gravity base and continuing the lay with precisely installed buoyance modules to achieve a mid water lazy loop before continuing  onwards to the FSO pull in point and into the hang off collar.

Services provided during the project

The work was performed on the Crest Odyssey I with installed SMD WROV, Survey and positioning systems, 12m Reel drive system, 40t 4x track tensioner, vertical lay chute, and bespoke fabricated work platform areas.

Basic Scope summary:

  • Flexible pre lay route survey, debris removal and turning bollard installation.
  • Install remove platform bell mouth cap, handover flexible to messenger for pullin.
  • Continue lay around turning bollard to gravity base infront of FSO, install bend stiffener and attach to gravity base.
  • Continue laying installing buoyancy modules to create mid water lazy Loop
  • Handover to FSO for pull in to hang off collar.
  • Subsea Survey and Positioning, as built survey and report.

Service Provided

  • Subsea MSV vessel (Crest Odyssey 1) for laying
  • Survey and Positioning
  • Subsea lift analysis and engineering
  • Provisioning of bespoke rigging and installation aids
  • WROV
  • Bespoke lay grillage and platforms on vessel
  • Installation of third party Reel drive, tensioner and vertical lay chute

 

Project outcome

Shelf completed the job in very challenging environmental conditions and changing schedule requirements to allow the field expansion to go live.

The project was notable for the extensive interfacing, project management and engineering required to be performed over 9 months in the lead up to the execution. Shelf were involved and interfacing in everything from installation engineering, lay analysis and lay equipment selection and configuration.