OneSubsea’s ‘cutting-edge’ tool enables Shell’s field to step up on the gas

September 5, 2025, by Melisa Cavcic

OneSubsea, a joint venture backed by SLB, Aker Solutions, and Subsea7, has revealed that its subsea compressor system, which recently came online at a Shell-operated natural gas field in the Norwegian Sea, will allow the operator to unlock new gas supplies for Europe.

After Shell’s Ormen Lange phase III project began production at the end of June 2025, OneSubsea highlighted that its subsea compressor solution was installed to boost recovery from the Ormen Lange field, described as the second-largest gas field off the coast of Norway.

OneSubsea claims that its compressor system, said to be the largest in the world, will help Shell unlock 30–50 billion cubic meters of additional gas reserves for export to Europe, enabling an increase in recovery from the field of up to 85%, equivalent to the gas supplies needed to heat up to 5 million homes next year alone.

While conventional compressors require perfectly dry gas to operate safely and efficiently, the firm’s solution, which includes the subsea wet-gas compressor, 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% and also tolerates sand and solids.

Mads Hjelmeland, OneSubsea’s CEO, commented: “This milestone represents a significant achievement not only for OneSubsea, but also for our customers and the wider energy industry. The Ormen Lange Phase 3 project truly demonstrates what we can achieve together, when bold vision meets cutting-edge innovation and execution capabilities.”

More gas for Europe as Shell turns on the taps at Norwegian field’s next chapter

Exploration & Production

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

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

The company underlines that the Ormen Lange Phase 3 project sets a record for the deepest installation of a subsea compression system ever in water depths of over 900 meters below sea level. The gas will be delivered to the Nyhamna gas plant 120 kilometers away, which is interpreted to set another record as the longest subsea step-out ever.

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

OneSubsea has won multiple assignments lately, including a contract with Equinor for an all-electric subsea production system (SPS) destined for a field in Norwegian waters.