Oil and gas company Taqa has filed plans for the decommissioning of the topsides of the Cormorant Alpha platform in the North Sea.
The Cormorant Alpha platform is located in Block 211/26 of the Northern North Sea (NNS), approximately 103 km northeast of Shetland and 41 km west of the UK/Norway median line. Installed in May 1978, the Cormorant Alpha platform produced first oil in December 1979.
Taqa took over the platform from Shell in 2008.
Current production from the Cormorant Alpha field is from 24 platform wells and five water injection wells. The platform was designed to fulfill four functions; a production facility, drilling facility, an oil pumping station for the Brent Pipeline System and a centre for telecommunications in the area.
Live crude is imported from the North Cormorant, Brent Charlie, and North Alwyn platforms. Crude entering the platform normally flows across the platform and is exported directly to the Sullom Voe terminal together with the Cormorant Alpha production.
The Cormorant Alpha platform consists of a four-leg Concrete Gravity Base Structure with a steel box girder structure supporting two levels of modules on the topsides and sits in a water depth of approximately 150 m. The Living Quarters (LQ) can accommodate 175 persons. The installed total weight of topsides is currently estimated to be approximately 25,546 te.
In its decommissioning plan, Taqa said that conducted to assess options for reuse of the Cormorant Alpha platform concluded that there are no credible reuse options for the topsides.
“This is principally due to the limited remaining life of the topsides structure due to fatigue and obsolescence issues and economic factors associated with converting the installation for any intended reuse purpose. Components from the topsides may be re-used if a suitable use can be found,” Taqa said.
Taqa now proposes to fully remove the Cormorant Alpha topsides and transport it to a suitable onshore yard facility for dismantling and recycling.
“Two possible methods of topsides removal are under consideration; single lift and modular removal,” Taqa said.
The first option would entail lift and removal to shore as a single unit, using a Single Lift Vessel (SLV). The second would include removal of the topsides in modular sections, using a Heavy Lift Vessel (HLV).
“At this stage, the specific method by which the removal activity will take place has not been determined. Both are potentially suitable. These decisions will depend to some degree on the proposals made by the eventual contractor,” Taqa said.
Topsides preparation work will be undertaken between 2023 and 2026 and topsides removal between 2026 and 2028.