Norwegian state-owned energy giant Equinor has kicked off the next phase of its subsea compression quest in the Norwegian Sea to up the gas recovery ante at its asset off the coast of Norway.
Partners in the Åsgard license – encompassing Equinor (operator with 35,01%), Petoro (34,53%), Vår Energi (22,65%), and TotalEnergies EP Norge (7,81%) – and the Mikkel license – consisting of Equinor (operator with 43,97%), Vår Energi (48,38%), and Repsol Norge (7,65%) – have started phase 2 of Åsgard subsea compression in the Norwegian Sea to help maintain production from the field by increasing the pressure in pipelines between the wells and the Åsgard B platform.
Following the approval of the first plan for development and operation (PDO) of Åsgard in 1996, the field came on stream with Åsgard A in 1999 and Åsgard B in 2000. The PDO for Åsgard subsea compression was approved in 2012 by the authorities, and the first phase of Åsgard subsea compression came online in 2015, described as the world’s first facility for gas compression on the seabed and the result of extensive technological development.
Trond Bokn , Equinor’s Senior Vice President for Project Development, commented: “In this project, Equinor, together with partners and suppliers, has further developed and qualified the next generation of compressor modules. The technology allows us to recover more gas from producing fields. Good resource utilisation is important to maintain high and stable production from the Norwegian continental shelf.”
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As the plans outlined that there would be a need for increased pressure in the long term to compensate for the pressure drop in the reservoirs, the first compressor module in phase two was replaced in 2023. This has now been followed by the second and final module, which has been installed at a depth of 270 meters.
Randi Hugdahl , Vice President for Exploration and Production for Åsgard and Kristin, underlined: “The compressor system has produced stably for ten years with almost 100% uptime. The system has so far contributed to increased value creation from the field of about NOK 175 billion.”
Equinor claims that the recovery rate for both phases from the Mikkel and Midgard fields will increase to 90% because of the compressor plant, amounting to an additional 306 million barrels of oil equivalent from the fields. The ÅSC station is situated in 270 meters of water on the Midgard field, about 40 kilometers from the Åsgard field center.
With a total weight of 5,100 tons, a footprint of 3,300 square meters, and towering 26 meters above the seabed, it is deemed to be the largest subsea processing plant ever installed. The station entails two identical compressor trains operating in parallel, each powered by a compressor with an electric motor capacity of 11.5 MW.
The Norwegian giant explains that the complete spare train is available in Kristiansund, which makes it possible to quickly replace parts if problems occur. The system is modular, much like Lego bricks, with several key components from the old compression modules overhauled and reused in the new modules.