Statoil plans use of subsea compressors

July 20, 2006
Statoil ASA plans within 6-7 years the first commercial use of subsea compressors to produce more natural gas from the Aasgard field in the Norwegian Sea.

By OGJ editors
HOUSTON, July 20 -- Statoil ASA plans within 6-7 years the first commercial use of subsea compressors to produce more natural gas from the Aasgard field in the Norwegian Sea.

"This means that the business potential on the Mikkel and Midgard deposits at Aasgard will be better exploited," said Knut Nordstad, senior adviser at Statoil's research center in Trondheim, where the technology was developed. "Gas compression may be relevant both for the Troll field in the North Sea and Snohvit in the Barents Sea," he said.

A compressor installed on the seabed would boost pressure in the gas flow to compensate for declining pressure in the reservoir. Gas recovered from the fields is expected to increase by 25%, or 30-40 billion cu m., when this technology is employed, said Statoil officials.

Seabed installation of the compressor is scheduled for 2012-13 in 250 m of water some 50 km from the Aasgard B platform. In connection with seabed processing, tasks such as pumping, separation, compression, and filtering are to be done on the seabed rather than on the platform. The technology will contribute to cost savings and will secure production until 2021, officials said.

Subsea compression is potentially safer, cheaper, and less risky than above-water systems, proponents claim. Reliability and control also are important issues, they said.

Seabed processing is particularly relevant in Artic waters, said company officials. If Statoil becomes a partner on the Shtokman field in the Russian sector of the Barents Sea, its experience with new seabed technology will be useful, said company officials.

Aasgard field began producing gas in 1999, and Aasgard B gas came on the following year.

Statoil and the other partners in the Aasgard license are investing more than 4 billion kroner in the project. Statoil is operator for Aasgard with 25% interest. Other licensees are Petoro 35.5%, Norsk Hydro AS 9.6%, Eni SPA 14.9%, Total SA 7.65%, and ExxonMobil Corp. 7.35%.