AMOG performed the riser system design verification for the dynamic riser and umbilical systems connecting the Ichthys Central Processing Facility (CPF) and FPSO to the subsea seabed architecture for all three major riser systems for the Ichthys LNG project.
The overall SURF EPCI contract awarded to McDermott was valued at over $2 billion, with dynamic risers being supplied by Technip and NOV, and umbilicals by Aker Solutions. The verification activities for each of the major riser systems described below included the following activities:
- Independent global riser system analysis
- Expert technical review of design documentation and verification of the global riser system analysis performed by the SURF EPCI contractor
- Expert technical review of design documentation and verification of the riser/umbilical system analysis performed by the three (3) flexible riser/dynamic umbilical suppliers
Riser System Design Verification - CPF North Face
AMOG performed a riser system design verification for the dynamic riser and umbilical system connecting the Central Processing Facility (CPF) to the subsea seabed architecture on the North Face of the CPF. The riser and umbilical system is configured in a Fixed S arrangement for both the flexible risers and the dynamic umbilicals, utilising a Riser Support Structure (RSS). The RSS structure weighs over 6,500 tonnes and is 100 m tall with a 130 m wide arch supporting the 25 large diameter flexible risers. The independent dynamic analysis considered the hydrotest, extreme and survival conditions expected at site during the 40 year design life. The independent analysis of the dynamic riser and umbilical configuration assessed the risers/umbilicals against acceptance criteria for tensions/ compressions, curvatures, seabed clearances and riser/riser, riser/mooring and riser/RSS interference. The independent analysis also included detailed modelling of bend stiffeners (including temperature effects), riser contact energies, riser wake interference and slugging.
Riser System Design Verification - CPF South Face
AMOG performed an umbilical system design verification for the dynamic umbilical system connecting the Central Processing Facility (CPF) to the subsea seabed architecture on the South Face of the CPF. The umbilical system consists of two umbilicals configured in a lazy wave, utilising discrete distributed buoyancy modules. The independent dynamic analysis considered both the extreme and survival conditions expected at site during the 40 year design life. The independent analysis of the dynamic umbilical configuration assessed the umbilicals against acceptance criteria for tensions/compressions, curvatures, seabed clearances, umbilical/umbilical interference and umbilical/mooring interference. The independent analysis also included detailed modelling of bend stiffeners (including temperature effects), umbilical contact energies and umbilical/seabed interaction.
Riser System Design Verification - FPSO
AMOG performed a riser system design verification for the dynamic riser and umbilical system connecting the Floating Production Storage and Offloading facility (FPSO) to the subsea seabed architecture. The FPSO riser and umbilical system is configured in a Lazy S arrangement for both the flexible risers and the dynamic umbilicals, utlising a Mid Depth Buoy (MDB). There are three sectors, each with a large MDB supporting five risers and umbilicals. The independent dynamic analysis considered the extreme and survival conditions expected at site during the 40 year design life. The independent analysis of the dynamic riser and umbilical configuration assessed the risers/umbilicals against acceptance criteria for tensions/ compressions, curvatures, seabed clearances and riser/riser, riser/mooring and riser/MDB tether interference. The independent analysis also included detailed modelling of bend stiffeners (including temperature effects), riser contact energies, riser wake interference and slugging.
The Ichthys LNG project is a Joint Venture between the operator INPEX (76%) and Total (24%) and is located in the Ichyths Field, Northern Browse Basin, Western Australia.