Overview

The world's first and only true subsea wet gas compressor

The OneSubsea multiphase compressor, a 2015 OTC Spotlight on New Technology Award winner, is the world’s first and only true subsea wet gas compressor with no requirements for an upstream separation facility or an antisurge system, which greatly simplifies the subsea system requirements. The compressor is a contrarotating machine specifically designed for pressure boosting of unprocessed wellstream. This unique configuration, developed in collaboration with Statoil and Shell, enables a compact and robust design that is easy to install by use of light intervention vessels and is based on the well-proven design developed for subsea booster pumps.

OneSubsea Multiphase Compressor

The subsea multiphase compressor is capable of handling high liquid contents without mechanical issues, with gas volume fractions typically in the range of 95% to 100%. This compressor represents a breakthrough in the subsea environment because it enables compression of the unprocessed wellstream without any need for preprocessing. This enables deployment of simplified subsea systems at lower capex and field development costs.

The main driver in the development of the multiphase compressor was to increase recovery rates and to cost-effectively increase the tieback distances of subsea gas fields. The Gullfaks field, operated by Statoil and located in the North Sea, saw the first commercial deployment in the world for subsea wet gas compression. Statoil estimates that the recovery rate will increase by 22 million barrels of oil equivalent by using the wet gas compression system. The wet gas compression station for Gullfaks was installed approximately 15 km away from the Gullfaks C platform.

Advantages

  • Continuous operation on all liquid fractions (0%–100%)
  • Operation in all flow regimes
  • Standard fluid film bearing technology
  • Surge-free operation requiring no antisurge system
  • Sand- and solid-tolerant design
  • Low speed that enables long step-outs without subsea variable speed drives
  • Low module weight (approx. 60 t) that enables intervention via light vessel