Statoil with partners Petoro and OMV have started the world´s first wet gas compression on the seabed of the North Sea Gullfaks field.​

The unique technology will increase recovery by 22 million barrels of oil equivalent (oe) and extend plateau production by around two years from the Gullfaks South Brent reservoir.

“We are very proud that we have been able to complete such a demanding pioneering project with start-up ahead of the original plan,” says Margareth Øvrum, executive vice president for Technology, Projects & Drilling (TPD).

“Subsea processing and gas compression represent the next generation oil and gas recovery, taking us a big step forward,” she says.

Statoil is the first company to apply subsea gas compression. In mid-September Statoil also started Åsgard subsea gas compression.

The two projects are the first of their kind worldwide, and represent two different technologies for maintaining production when the reservoir pressure drops after a certain time.

Subsea compression has stronger impact than conventional platform-based compression. It is furthermore an advantage that the platform avoids increased weight and the extra space needed on the platform for a compression module.

Subsea compression is an important technological leap to further develop the concept of a subsea factory.

Looking for more candidates

“This is one of several important projects on Gullfaks for improved recovery and field life extension. The recovery rate from the Gullfaks South Brent reservoir may be increased from 62% to 74% by applying this solution in combination with other measures,” says Kjetil Hove, senior vice president for the operations west cluster.

It is also possible to tie in other subsea wells to the wet gas compressor via existing pipelines. The station has already been prepared for new tie-ins.

“We see great opportunities for wet gas compression on the Norwegian continental shelf. It is an efficient system and a concept that can be used for improved recovery on small and medium-sized fields. We are searching for more candidates that are suitable,” says Hove.

Standardisation and simplification

The advantage of a wet gas compressor is that it does not require gas and liquid separation before compression, thereby simplifying the system considerably and requiring smaller modules and a simpler structure on the seabed.

“The Gullfaks wet gas compressor is a unique, compact and cost-effective solution. The concept may be standardised by applying well-known technology components,” says Øvrum.

Successful installation campaign

The system consists of a 420-tonne protective structure, a compressor station with two five-megawatt compressors totalling 650 tonnes, and all equipment needed for power supply and system control on the platform.

Extensive preparations had been made on Gullfaks C before the subsea compressor could be started, including modifications and preparation of areas as well as installation of equipment.

Gullfaks licensees: Statoil (operator) (51%), Petoro (30%), OMV (19%)​​​​​​

About Statoil

Statoil ASA (OSE: STL, NYSE: STO) is an international energy company with operations in 36 countries. Building on 40 years of experience from oil and gas production on the Norwegian continental shelf, we are committed to accommodating the world's energy needs in a responsible manner, applying technology and creating innovative business solutions. We are headquartered in Stavanger, Norway, with approximately 23,000 employees worldwide, and are listed on the Oslo and New York stock exchanges.

About OMV Aktiengesellschaft

With Group sales of EUR 36 bn and a workforce of around 25,500 employees in 2014, OMV Aktiengesellschaft is one of Austria’s largest listed industrial companies. In Upstream, OMV has a strong base in Romania and Austria and a balanced international portfolio. 2014 daily production stood at approximately 309,000 boe/d. In Downstream, OMV has an annual refining capacity of 17.8 mn tonnes and approximately 4,100 filling stations in 11 countries as of end of 2014. OMV operates a gas pipeline network in Austria and gas storage facilities in Austria and Germany. In 2014, gas sales volumes amounted to 123 TWh.

About Petoro

The Norwegian state has substantial holdings in production licences on the Norwegian
continental shelf (NCS) through the State’s Direct Financial Interest (SDFI).
These assets are managed by Petoro AS. The company’s most important job is to help ensure the highest possible
value creation from the SDFI to the benefit of the whole of Norway.