The Nganhurra FPSO operated by Woodside is to be disconnected from its riser turret mooring (RTM) and permanently removed from site. As part of the engineering works involved with the planning of this operation Linch-pin has assessed the options available to Woodside for the RTM decommissioning.
One developed solution involved downending the 80m long steel structure to the horizontal ready for wet tow by utilising the ballastable internal compartments. This controlled downending is made difficult by the almost 400t of unballastable solid iron ore ballast in the lower most compartment.
The dynamic analysis works was carried out utilising both Sacs and OrcaFlex. Offshore activities to disconnect the FPSO from the RTM are expected to commence Q4 2017.