A ground-breaking SLB OneSubsea™ subsea compressor system recently came online at Shell’s Ormen Lange field, the second largest gas field in Norway.

Why it matters
This OneSubsea compressor system — the largest in the world — will help Shell, the operator for the Ormen Lange field, unlock 30–50 billion cubic meters of additional gas reserves for export to Europe, enabling an unprecedented increase in recovery from the field of up to 85%.

The additional recovery from the field is equivalent to the gas supplies needed to heat up to 5 million homes next year alone.

Record-setting project
The Ormen Lange Phase 3 project sets a record for the deepest installation of a subsea compression system ever in water depths more than 900 meters below sea level. The gas will be delivered to the Nyhamna gas plant 120 km away — setting another record as the longest subsea step out ever.

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

System deep dive
SLB OneSubsea’s award-winning subsea multiphase compressor system includes 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.