Statoil ASA has brought the first subsea gas compression plant online at Aasgard field in the Norwegian Sea. The company says the technology will add 306 million boe over the life of the field.
Compression closer to the well increases recovery as well pressure decreases over time. Traditionally, compression plants are installed on platforms or onshore. The Aasgard subsea plant is on the ocean floor in 300 m of water close to the wellhead.
Statoil says that moving gas compression from the platform to the wellhead increases recovery rates and the life of a field. Prior to gas compression, gas and liquids are separated out and, after pressure boosting, recombined and sent by pipeline about 40 km to Aasgard B.
Recovery from the Midgard reservoir on Aasgard will increase to 87% from 67%, and to 84% from 59% in the Mikkel reservoir, the company said. Siri Espedal Kindem, senior vice-president for Statoil’s Aasgard operations, said that the life of both reservoirs will be extended to 2032.
Statoil’s subsea gas compression project cost about 19 billion kroner and took more than 5 years to complete (OGJ Online Nov. 10, 2010).
Statoil operates Aasgard and owns 34.57% with partners Petoro AS 35.69%, Eni Norge AS 14.82%, Total E&P Norge AS 7.68%, and ExxonMobil E&P Norway AS 7.24%.
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