World's First Subsea Gas Compression Systems Operate in the North Sea

Overall, project cost were just above NOK 19 billion. Many small and big suppliers have helped to develop the sophisticated underwater compressor system. Establishing the necessary support functions onshore has been an important and substantial part of the project. A spare compression train will be stored in custom designed halls at the onshore supply base Vestbase in Kristiansund. “High-quality, regular maintenance of the subsea modules will also be performed here, helping ensure operational excellence for Åsgard,” says Espedal Kindem.

Technology for the Future and new Potentials

The Midgard and Mikkel gas reservoirs have been developed using subsea installations. The two gas compressors now installed on the seabed are located close to the wellheads.

Moving the gas compression from the platform to the wellhead substantially increases the recovery rate and life of the fields. Prior to gas compression, gas and liquids are separated out, and after pressure boosting recombined and sent through a pipeline some 40 kilometres to Åsgard B.

Statoil and its partners put the first subsea gas compression facility on line at Åsgard in the Norwegian Sea. Subsea compression will add some 306 million barrels of oil equivalent to total output over the field’s life. (Picture: Øyvind Hagen/Statoil ASA)

In addition to improving recovery subsea gas compression will be more energy efficient than the traditional topside solution. The technology reduces significantly energy consumption and CO₂ emissions over the field’s life.

Going Underwater: Future Technology aims for the Deep

Today almost 50 percent of Statoil’s production is recovered through some 500 subsea wells. Statoil’s subsea expertise is essential to successful production efficiency improvement and increased oil recoveryefforts.

The world's first subsea gas compression system went on stream recently at the Statoil-operated Åsgard field. Aker Solutions has delivered the subsea compression system for this field development. (Picture: Aker Solutions)

“Subsea gas compression is the technology for the future, taking us a big step closer to our ambition of realising a subsea processing plant, referred to as the subsea factory”, says Øvrum. Such a plant will facilitate remotely controlled hydrocarbon transportation. Current topside operations will thus be moved to the seabed, allowing oil and gas to be recovered that would not otherwise be profitable. This is an important element of increased recovery on the Norwegian continental shelf.