Deepest-Ever Subsea Compression Systems Come Online Offshore Norway (Video)

(Credit: Screensho/Video by Shell)

Two SLB OneSubsea subsea compressor stations recently came online at Shell’s Ormen Lange field, the second largest gas field in Norway, setting the record for the deepest installation of such systems ever.

The SLB OneSubsea subsea compressor stations, installed more than 900 meters below sea level in Norwegian Sea, represent the deepest subsea compression system ever deployed.

Gas is transmitted 120 kilometres to Shell’s Nyhamna processing plant onshore, also marking the longest subsea ‘step-out’ in history.

Shell said the technology will unlock an additional 30 to 50 billion cubic meters of gas reserves from Ormen Lange as part of the project’s phase III, raising recovery to as much as 85% and providing increased supply to Europe.

SLB OneSubsea’s award-winning subsea multiphase compressor is said to be the world’s first and only true subsea wet-gas compressor.

Conventional compressors require perfectly dry gas to operate safely and efficiently. The subsea compression system from OneSubsea, on the other hand, can operate with the unprocessed multiphase well stream, including condensates, produced water, and mono ethylene glycol (MEG), with liquid fractions ranging from 0% to 100%. It also tolerates sand and solids.

The Ormen Lange system uses two compression stations, each containing two compression modules. Each compressor can provide up to 50-bar differential pressure, configured in parallel for a large volumetric flow capacity.

The 32-MW subsea multiphase compression system will use onshore variable speed drives (VSDs) located 120 km away, eliminating subsea VSDs or topside alternatives to improve project economics.

The Ormen Lange phase III came online in June 2025. The gas field located in the Norwegian Sea, 120 km from the onshore processing and export facility at Nyhamna. The gas is exported to European markets through Langeled and the Norwegian gas export system.

Shell is the operator (17.8%) of the Ormen Lange field, with Vår Energi (6.3%), Petoro (36.5%), Equinor Energy (25.3%) and Orlen Upstream Norway (14%) as partners.

• Shell Boosts Production from Norway’s Ormen Lange Offshore Field