GP3 FPSO - Xodus Group
Client: Maersk Oil
Location: UK Continental Shelf

Supporting safe and efficient operations.

Xodus Group evaluates processes and procedures in parallel with a programme of offshore as-built surveys for the GP3 FPSO.

The Global Producer III (GP3) Floating Production, Storage and Offloading (FPSO) vessel was originally stationed on the Leadon field. During 2006 the vessel was brought off location and modified to be installed on the Dumbarton field. The conversion to the Dumbarton field was performed at low cost and under a fast schedule, with sail-out at the end of 2006.

In the four years following production start-up at Dumbarton, operator Maersk Oil recognised the need to further improve the maintenance, integrity and reliability measures adopted to enhance safety and operational performance. Xodus Group subsequently carried out an extensive programme of work and validation exercises to assist with improving the safe and efficient production and processing of hydrocarbons by the GP3.

Assignment scope

  • Undertake eight month offshore survey (four persons back-to-back rota) to 230 as-built Piping and Instrumentation Diagrams (P&IDs) – extensive onshore programme to review offshore anomaly findings and complete drafting of P&IDs and detailed review of cause and effects
  • Consider data verification of Locked Open / Locked Closed (LO / LC) valve register, safety related device register, High Pressure / Low Pressure (HP / LP) interface register
  • Extensive design verification to validate and update the design envelope, including detailed capacity assessment of the existing HYSYS software model and update to include current well composition, gas oil ratios, Hydrogen Sulphide (H2S) levels, process operating conditions – consideration of oil processing, gas processing, produced water treatment, injection and disposal, utilities, drains, shutdown logic and long term over-rides, full relief valve calculation, flare and blowdown study and flarenet modelling
  • Undertake full review and update of platform operational and control procedures
  • Chair and coordinate full platform process system Hazard and Operability Study (HAZOP).


  • Execution of 20,000 man-hour, validation and verification programme
  • Full process system HAZOP completed in eight weeks
  • 230 as-built P&IDs.