Technology jointly developed by GE Oil & Gas and Aker Kværner has been selected for a pilot program in Norway’s Ormen Lange natural gas field that will be the first subsea compression project of its kind in the world.

The contract for the pilot project was awarded to Aker Kværner by Norsk Hydro, one of the owners of the natural gas field, the largest under development on the Norwegian continental shelf.


Working with Aker Kværner, GE Oil & Gas has completed the conceptual design of a 12-MW subsea compressor, the largest ever developed for subsea applications, and is set to begin construction of the machine to be tested in the pilot project.


The aim of the pilot project is to evaluate whether a subsea compression station, at approximately 2,952 ft (900 m) of water depth, is a viable alternative to an offshore platform. In the past, it has not been profitable to exploit many natural gas subsea fields, particularly those in depths of 1,640 ft (500 m) or more, largely due to the cost of conventional offshore platforms.


Subject to the Ormen Lange partners’ final approval, Aker Kværner’s subsea compression station pilot project will undergo controlled endurance tests from 2009 to 2011 at a gas treatment facility in Nyhamna, Norway.


Since the early 1990s, GE Oil and Gas has been working to develop a robust subsea compression system, ranging from the testing of the first 850-kW subsea compressor unit in 1992 to today’s generation of advanced high-speed, oil-free subsea compressors designed for the economic recovery of natural gas from deepwater fields. A 2.5-MW conceptual design, called the Blue-C Subsea Centrifugal Compressor, was unveiled at the Offshore Northern Seas Conference in 2002. The new high-speed, oil-free, 12-MW subsea compressor has evolved from that technology.


To address the constraints of a subsea application, the new design has been focused on the optimization of the compression train, featuring a vertical and compact configuration to minimize the footprint and to facilitate machine operation with good drainage of possible liquid parts.


Because reliability of the compression train is a key requirement for subsea applications, the equipment was designed to minimize the number of critical parts.


The new subsea compressor module, an extremely compact solution, is equipped with active magnetic bearings and includes a high-speed electric motor directly coupled with a centrifugal compressor in a vertical configuration.


The Ormen Lange subsea compressor module is a turnkey system designed to be installed at a water depth of 2,788 ft to 3,280 ft (850 m to 1,000 m) and at a distance of 75 miles (120 km) from the Nyhamna onshore terminal.