The ethos of subsea processing has always been about moving as much of the conventional processing capabilities from the surface to the seafloor—helping to debottleneck topside facilities and subsea pipelines, increasing recovery rates and, in some cases, creating new possibilities for profitable field developments.

Technological development has accelerated in recent years, with core technologies such as boosting, separation, power and compression now routinely considered as part of new development scenarios. They also are seen as an opportunity to improve return on investment on aging brownfield projects.

GE Oil & Gas, having worked in the subsea processing space for more than 20 years, has its inventory of knowledge and technology contained in what is called the “GE Store,” which allows it to tap into different technological areas.

For the subsea sector, this means leveraging its capabilities in rotating equipment, flow assurance, subsea production, water treatment, power systems, and advanced monitoring and diagnostics.

Gas compression
Subsea gas compression is one emerging technology that can significantly improve the economics of many mature gas fields. By placing such systems on the seafloor, the E&P industry can accelerate production while eliminating the need for costly topside facilities.

GE’s Blue-C technology is at the heart of both its subsea dry and wet gas compression system. Initially designed for dry gas, a wet gas version of the compressor that can handle up to 5% liquid has now been developed, eliminating the need for a subsea separator and resulting in a more compact and lower cost system.

The Blue-C is a high-capacity centrifugal compressor designed for maximum reliability that has undergone exhaustive testing in a submerged environment to ensure full optimization for subsea operation. It can be configured to run from 4 MW to 20 MW, providing the flexibility to deliver systems for use in both small and large fields or to run with a single compressor or more than one compressor in parallel.

A schematic of GE’s Blue-C compressor is shown. (Source: GE Oil & Gas)

GE’s subsea compression system eliminates the need for costly topsides facilities. (Source: GE Oil & Gas)

Subsea boosting
Even in challenging environments such as long-distance tiebacks, low-pressure reservoirs or wells with difficult flow assurance conditions, subsea boosting can be used to unlock and enable access to these assets.

GE Oil & Gas has drawn inspiration from its GE Aviation sister business to explore a new boosting system approach that has the potential to fundamentally change and simplify subsea boosting. The company is collaborating closely with leading operators to build a demonstrator test unit aimed at confirming its ability to handle a variety of flow rates and fluid compositions.

The system can be configured with either centrifugal or helico-axial stages, with each system again designed for high reliability. Key benefits include life-cycle cost reduction, operational flexibility, and reduced topside and subsea footprint compared to conventional subsea boosting.

In addition to the existing market for subsea boosting, this new concept provides the potential to unlock additional barrels in many brownfield applications where there is either not enough space topsides to accommodate the equipment associated with conventional boosting systems or where the cost of conventional systems is prohibitive.

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