World’s first subsea wet gas compressor station set for installation in 2015

The world’s first subsea wet gas compressor station is now ready for the final testing at Horsøy before being prepared for installation and hook-up to Gullfaks C, an oil and gas field in the Norwegian sector of the North Sea, in 2015 Statoil has announced.

The compressor is expected to help extend the field’s productive life by 22 million extra barrels of oil equivalent from the Gullfaks South Brent reservoir.

According to the project manager for the Gullfaks subsea project Bjørn Birkeland the compressor which will help improve oil recovery solutions for the Norwegian giant explorer is a result of works dating as back as 2008.

“The compressor in principle builds on Framo Engineering’s multi-phase pumps, which have been used by Statoil for several decades, including on the Gullfaks field,” says Bjørn.

The compressor is developed in cooperation with One Subsea (formerly Framo Engineering), and large parts of the compressor station have been built by suppliers and sub-suppliers in western Norway and in the Bergen region.

The delivery from One Subsea consists of a 420-tonne protective structure, a compressor station with two compressors totalling 650 tonnes, and all necessary topsides equipment for power supply and control of the plant.

The first period after start-up of this type of subsea installation will be important with a view to gaining operating experience to be drawn on by other fields that may consider using this type of technology.

The compressor station has been mechanically commissioned and test-assembled and is now ready for the final system integration tests implemented by One Subsea at Horsøy.

The last test phase will verify that all units of the new subsea compressor station work as expected.

We now have control of the main pieces, so in the future the challenge is to reuse these, putting them together in ways that suit the individual reservoir. Close and good cooperation between operations, project and technology communities will be key to the successful achievement of this,” says Roald Sirevaag, Statoil vice president subsea technology and operations.

Compression on the seabed gives a better effect than a conventional topside compressor as well as there is an advantage that the platform avoids the increase in weight and space a topside compression module requires.

The advantage of a wet gas compression facility is that it does not require any treatment of the well stream before compression a feature that makes for smaller modules and a simpler construction on the seabed.