Heerema Marine Contractors’ Thialf has returned to Shell UK Limited’s Goldeneye wellhead platform to remove it after first having installed the structure in 2003. The operations included removing the 1280-metric-tonne topside and the 3019-metric-tonne jacket before transportation to the AF Environmental Base in Norway for recycling and reuse.
The Goldeneye platform was located in the Central North Sea, in the United Kingdom Continental Shelf, around 100 kilometres northeast of the Aberdeenshire coast. The platform included five platform wells in 120-metre 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.
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Removal campaign
The Goldeneye platform was removed using Heerema’s reverse installation method, starting with removing the 1280-metric-tonne 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 -3 metres below the seabed. After which, the 3019-metric-tonne jacket was safely removed and remained suspended in Thialf’s cranes for transportation to Vats, Norway.
The Goldeneye platform has been safely set down at the AF Environmental Base yard to be dismantled for reuse and recycling. It is anticipated that over 97 per cent of the material will be recycled.
Thialf modifications
Thialf will now undergo yard maintenance, including modifications to the vessel’s A-Frame to enable Thialf to expand its service area and deliver solutions in the Baltic and the Black Sea regions.
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Pictures by Heerema Marine Contractors.
