Equinor and partners in Asgard and Mikkel licences have started phase 2 of Asgard subsea compression in the Norwegian Sea.
The project will help maintain production from the field by increasing the pressure in the pipelines between the wells and the Asgard B platform.
“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," says Trond Bokn, Equinor's senior vice president for project development.
The first plan for development and operation (PDO) of Asgard was approved in 1996. The field came on stream with Asgard A in 1999 and Asgard B in 2000. In 2012, the PDO for Asgard subsea compression was approved by the authorities, and the first phase of Asgard 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.
"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," says Randi Hugdahl, vice president for Exploration and Production for Asgard and Kristin.
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.
Licensees Åsgard: Equinor Energy AS (operatør) 35,01%, Petoro AS 34,53%, Vår Energi ASA 22,65% og TotalEnergies EP Norge AS 7,81%.
Licensees Mikkel: Equinor Energy AS (operatør) 43,97%, Vår Energi ASA 48,38% og Repsol Norge AS 7,65%.
Facts
- The ASC station, located in 270 meters of water on the Midgard field, about 40 km from the Åsgard field centre, is an impressive subsea structure.
- 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 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, much like Lego bricks.
- A number of key components from the old compression modules have been overhauled and reused in the new modules.
Main suppliers
Development and delivery of the new compressors
- Everllence (formerly MAN Energy Solutions)
Development and delivery of the new compressor modules
- OneSubsea AS (formerly Aker Solutions Subsea AS)
- Construction of both modules has been done by Aker Solutions AS, Egersund
Marine Installation
- TechnipFMC in 2023
- Ocean Installer in 2025
Functional test, full-scale in pool and with hydrocarbons
- Carried out at Equinor's test facility (K-lab) at Kårstø
System Integration Test
- Carried out at Vestbase, Kristiansund