Heerema Marine Contractors’ giant semi-submersible crane vessel (SSCV) Thialf has removed Shell’s Goldeneye wellhead platform, located in the UK North Sea, after installing the structure in 2003.
Shell filed its decommissioning programme for the Goldeneye field installations and pipelines to the UK authorities in November 2018 and received approval for the plan about a year later.
The Goldeneye field is a normal temperature, normal pressure gas condensate field located in blocks 14/28b, 14/29a, 20/3b and 20/4b of the United Kingdom Continental Shelf (UKCS) in the central North Sea, approximately 100km North-East of St. Fergus.
Heerema said on Monday that its giant SSCV removed the Goldeneye platform. The operations included removing the 1280 metric ton topside and the 3019 metric ton jacket before transportation to the AF Environmental Base in Norway for recycling and reuse.
The Goldeneye platform included five platform wells in 120 m water depth with a direct tie-back via the Goldeneye pipeline to the St. Fergus onshore facility. It was operational as a gas-producing field from 2004, and cessation of production was granted in 2011.
The Goldeneye platform was removed using Heerema’s reverse installation method, starting with removing the 1280 metric ton topside in a single lift. After removal, the topside was transferred to Thialf’s deck for transportation.
The Goldeneye jacket involved cutting skirt piles using Deco Subsea’s internal abrasive water jet cutting techniques at -3m below the seabed. After which, the 3019 metric ton jacket was removed and remained suspended in Thialf’s cranes for transportation to Vats, Norway.
The Goldeneye platform has been set down at the AF Environmental Base yard in Vats, Norway, to be dismantled for reuse and recycling. It is anticipated that over 97 per cent of the material will be recycled. Thialf will now undergo yard maintenance, including modifications to the vessel’s A-Frame to enable it to expand its service area and deliver solutions in the Baltic and the Black Sea regions.