Equinor, Partners Bolster Åsgard Production with Subsea Compressors Upgrade

Equinor and partners in Åsgard and Mikkel licenses have started the second phase of Åsgard subsea compression in the Norwegian Sea, with the aim to maintain production from the field by increasing the pressure in the pipelines between the wells and the Åsgard B platform.

The first plan for development and operation (PDO) of Åsgard was approved in 1996. The field came on stream with Åsgard A in 1999 and Åsgard B in 2000. In 2012, the PDO for Åsgard subsea compression was approved by the authorities, and the first phase of Åsgard subsea compression came on stream in 2015.

This was the world's first facility for gas compression on the seabed and the result of extensive technological development.

The plans described 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, now the second and final module has been installed, at a depth of 270 meters.

With a total weight of 5100 tons, a footprint of 3300 m2 and towering 26 meters above the seabed, it is the largest subsea processing plant ever installed.

The ÅSC station, located in 270 meters of water on the Midgard field (Credit: Equinor)

The station consists of two identical compressor trains operating in parallel, each powered by a compressor with an electric motor capacity of 11.5 MW.

A complete spare train is available in Kristiansund, which makes it possible to quickly replace parts if problems occur. The system is modular, with a number of key components from the old compression modules overhauled and reused in the new modules.

Combined for both phases, the recovery rate from the Mikkel and Midgard fields will increase to 90% due to the compressor plant. This amounts to an additional 306 million barrels of oil equivalent from the fields.

The Åsgard licence is operated by Equinor, which holds 35.01%, alongside Petoro with 34.53%, Vår Energi with 22.65% and TotalEnergies EP Norge with 7.81% stakes. The nearby Mikkel license is also operated by Equinor with a 43.97% stake, together with Vår Energi with 48.38% and Repsol Norge with 7.65% interests.

“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 utilization is important to maintain high and stable production from the Norwegian continental shelf," said Trond Bokn, Equinor's senior vice president for project development.