Offshore staff
OSLO, Norway — DeepOcean has completed a subsea decommissioning project for an unnamed company in the central North Sea, achieving a 98% recycling rate for the removed equipment.
The program covered three fields and involved more than 300 vessel days during a six-month offshore campaign to recover almost 9,000 metric tons of subsea infrastructure.
Highlights of the campaign included flexible riser and umbilical recovery; a mid-water arch release and tow; the removal of a nine-leg FPSO mooring system; retrieval of various piled and non-piled structures including production manifolds and a subsea safety isolation valve module; removing concrete mattresses, general debris recovery and subsea rock installation.
The company’s office in Aberdeen managed and engineered the work, with support from other branches in Haugesund and Stavanger in Norway.
DeepOcean deployed multiple vessels from the fleet, but the main protagonists were the Normand Jarstein and the Edda Freya hybrid battery-powered vessel. More than 700 concrete mattresses were transferred to Normand Jarstein using the UTROV mattress recovery system, with no dropped objects.
As for the removal of the FPSO mooring system, DeepOcean undertook pump-out and recovery of three 7-m-diameter suction anchors weighing about 110 metric tons onto Edda Freya. The teams also recovered more than 3 m of studless mooring chain and 7.7 km of spiral strand.
Finally, the company also performed an external dredge and cut of the remaining six 5-m suction anchors at a depth of 3 m below the seabed.
06.30.2023
