Scope
Inpex issued tenders for a scope to design and install the subsea Umbilicals, Risers and Flowlines (URF) for the Ichthys project in the Browse Basin. Included in this scope was the Ichthys Riser Support Structure or RSS, a unique and innovative fixed subsea structure supporting 25 to 30 flowline and umbilical flexible risers, in an ‘S’ configuration, from the seabed to the floating Central Processing Facility (CPF). As part of their tenders, four (4) suppliers submitted concept designs for the RSS. Cube was engaged in the period leading up to and following the award to provide structural technical expertise.
Outcome
Cube performed technical evaluations and assessments of these concepts including technical feasibility and compliance reviews. The installation of the completely submerged structure and the shallow foundations on calcareous soils to resist seismic loading conditions proved to be challenging. Cube’s insightful input into the designs during the tendering process led to major modifications and improvements to the concept. Cube’s recommendation to continue and extend FEED into the first 6 months following award was taken up.
During FEED and detailed design, Cube assisted with validation and verification of the structural foundation analysis and design.
Detailed design and installation of the RSS went smoothly and the world’s largest subsea structure was installed in 2014.
RSS Tower 110m high in 250m water depth, 6,500 tonnes
RSS Arch 120 metres long and 20 metres wide.
Use the following link:
http://www.mcdermott.com/wp-content/uploads/2016/08/Ichthys-081616.pdf
