Okha FPSO RTM Mooring Wire Rope Changeout

The reconnection wire rope assembly for the Riser Turret Mooring (RTM) of Woodside Energy Limited’s (WEL) Okha Floating Production, Storage & Offloading (FPSO) Vessel was recently replaced as it was approaching the end of its working life. Previously the wire rope assembly had been replaced using subsea divers, however, Woodside requested AEC develop a procedure for replacing the 6.7t wire rope without use of divers.

AEC developed a rope replacement procedure based on transferring directly from the RTM to an Anchor Handling Tug (AHT). Throughout the project AEC conducted the following key activities:

  • Catenary analysis of the wire assembly spanning between the RTM and the AHT
  • Assessment of winch load increases due to friction around bends within the RTM
  • Design of structural aids for guiding the wire rope through the RTM
  • Condition assessment of the existing wire rope
  • Specification of rigging equipment required for the procedure
  • Preparation of a procedure document and detailed sequence drawings
  • Management of the fabrication of the structural aids and the supply of the rigging and equipment for the procedure
  • Project management & site supervision for spooling the wires in Karratha
  • Site engineer attendance during the rope replacement on the vessel

The rope was successfully replaced on station in late 2016 using the RTM-AHT procedure.

For more information on the Okha FPSO RTM Mooring Wire Rope Changeout Project please visit our Case Study.