First Subsea Wet Gas Compressor Installed

After several years of technology development, construction and testing the first subsea wet gas compressor in the world is now installed at the Gullfaks C platform in the North Sea.

In May and June Gullfaks subsea compressor project (GSC) completed successful structure and module installation campaigns for the subsea station. The compressors were installed at the end of June.

Subsea wet gas compression at Gullfaks C will add 22 million barrels of oil equivalent, and extend plateau production by about two years.

“The installation campaigns have been successfully performed by Subsea Seven,” says project manager Bjørn Birkeland. The project has now entered the last phase, testing and preparing for hand-over and start-up in the last quarter of this year.

“This is the first compressor of its kind in the world. It is a milestone, not just towards the compressor start-up, but also for Statoil (STO)’s subsea factory visions,” says Steinar Konradsen, owner representative for the project.

Testing of the complete compressor station still remains, but this work is underway and the project is on schedule.

Considerable preparations for the start-up of the subsea compressor have been made on Gullfaks C as well. This work, performed by Apply Sørco, is now in the final stages.

The compressor represents a robust and flexible measure to improve oil recovery (IOR) for the Gullfaks licence. The compressor will now be hooked up between the L and M subsea templates and Gullfaks C. It is also possible to tie in other subsea wells to the compressor through existing pipelines. 

This may have benefits far beyond the assumptions at the basis for the project decision

“Subsea wet gas compression is a game changer for subsea processing, and an important technology to increase recovery also on other fields,” Konradsen emphasises.

The protective structure and compressor station were installed in early May by the heavy lift vessel Oleg Strashnov. On 26 June the compressor and cooling modules were lowered into place from the Seven Viking.

The plant will be tied back to the Gullfaks C platform in the late summer and autumn.

The Gullfaks technology solution is a wet gas compressor which does not require any treatment of the well stream before compression.

Subsea compression provides a greater effect than a conventional topside compressor. In addition the platform avoids extra weight and space required by a topside compression module.

Statoil is currently implementing two subsea compression projects at Åsgard and Gullfaks on the Norwegian continental shelf (NCS) together with its licence partners. The projects represent important pieces of the jigsaw puzzle of designing the subsea factories of the future.