Subsea Compressor Now And Subsea Factory Later!


 Statoil, Petoro and OMV have partnered to start a revolution in recovery gas from under the sea by starting the first wet gas compressor the seabed of the North Sea Gullfaks field.  The unique technology will increase gas production by 22 million barrels of oil equivalent (oe) and extend plateau production by around two years.

Margareth Øvrum, executive vice president for Technology, Projects & Drilling (TPD), was jubilant that the next generation project was completed ahead of schedule.  Extensive preparations had been made on Gullfaks C before the subsea compressor could be started, including modifications and preparation of areas as well as installation of equipment.

The two independent technologies of subsea gas compression were started by Statoil in mid-September for maintaining production when the reservoir pressure drops after a certain time.  In a wet gas compressor, gas and liquid separation before compression is not required thereby simplifying the system considerably.  It works with smaller modules and a simpler structure on the seabed. Subsea compression ensures improved recovery and extended field life.  It is also possible to tie in other subsea wells to the wet gas compressor via existing pipelines.  The station has already been prepared for new tie-ins.

Subsea compression has the advantage of avoiding the conventional platform based compression which requires  the extra space for a compression module.  “The subsea compression is the first step for developing the concept of a subsea factory.  The recovery rate from the Gullfaks South Brent reservoir may be increased from 62 percent to 74 percent by applying this solution in combination with other measures,” says Kjetil Hove, senior vice president for the operations west cluster.  The wet gas compression opens up new opportunities in the Norwegian continental shelf for efficient and improved recovery on small and medium-sized fields The system consists of a 420-tonne protective structure, a compressor station with two five-megawatt compressors totalling 650 tons, and all equipment needed for power supply and system control on the platform.

Source: Statoil