Norway Approves Second Subsea Compressor
The Norwegian Petroleum Directorate has granted Statoil consent for the start-up and operation of a subsea wet gas compressor and umbilical on the Gullfaks field in the North Sea.
The Gullfaks project is the second major seabed gas compression project that will be initiated, after the Norwegian Petroleum Directorate granted consent for the start-up of Åsgard subsea compression in July 2015. This was the first subsea wet gas compressor in the world.
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. The gas is compressed on the seabed, raising the pressure in the pipelines. There is no need for separation in the system, so gas and liquids are boosted together in the same machine.
"Technology development is a key to improved recovery and extended lifetime for fields on the Norwegian shelf," says principal engineer Astri Fritsen of the Norwegian Petroleum Directorate.
For Gullfaks, this gas compression means extended lifetime and an increase in the gas recovery rate from Gullfaks Sør Brent from 62 to 74 per cent.
The compressor station and the umbilical installed on the seabed on Gullfaks will push the well stream from templates D, L, M, and N up. Production is scheduled to start no later than October of this year.
In addition to accelerating gas production and extending the period when the gas capacity on the Gullfaks C facility is utilized, the new infrastructure will increase the gas and condensate reserves from the reservoirs on Gullfaks Sør Brent and Rimfaks Brent.
According to Fritsen, the technology can be used on other new and existing fields in the future.
The main Gullfaks field lies in block 34/10 in the northern part of the Norwegian North Sea. It has been developed with three large concrete production platforms.
The Gullfaks A platform began production on 22 December 1986, with Gullfaks B following on 29 February 1988 and the C platform on 4 November 1989.
Produced oil is loaded directly into shuttle tankers on the field, while associated gas is piped to the Kårstø gas treatment plant north of Stavanger and then on to continental Europe.