Åsgard – one year on

One year on, Statoil has announced impressive results from its Åsgard subsea compression system, while the project partners intend to take the technology to the next level

Just over a year ago, in September 2015, Statoil and a number of engineering collaborators began production from the world’s first subsea gas compression system at the Åsgard field in the Norwegian Sea. In the interim, the system has run “like a Swiss clock with practically no stops or interruptions,” the operator recently stated.

Requiring a template the size of a football pitch (75m x 45m x 20m), two 11.5-MW HOFIM™ motor-compressor-units are expected to boost recovery from the Mikkel and Midgard reservoirs by 306 million boe, and extend their life until 2032. The wellstream from both fields, built as subsea installations and located 50 and 70 km away respectively, will be sent from the compressor in the same pipeline to the Åsgard B platform.

Working with engineers and suppliers Aker Solutions, MAN and Technip, Statoil qualified more than 40 new technologies during the project, many of which it now intends to re-use in other projects. 

“We have built test facilities at K-lab, storage and maintenance capacity at Vestbase, and we have access to ships that are capable of handling installation of large subsea modules. By reusing this technology, we have great opportunities for simplification and efficiency improvements, and for reducing carbon footprints of future gas compression systems,” commented vice president for Åsgard operations Halvor Engebretsen.

Adding to the company’s claims of Swiss clock-like accuracy, Engebretsen said: “Quality in all sections of the project and also during operation has contributed to maintain a system regularity of close to 100% through its first year of operation.”

“During the first year we have raised production by an excess of 16 million boe. Based on today’s prices the value added amounts to more than 5 billion kroner (US$600 million),” says Engebretsen. The recovery rates from the Midgard and Mikkel reservoirs on Åsgard have been raised from 67% to 87% and from 59% to 84% respectively.

Compacting compressors

With the first year of the project having been declared a success, Aker Solutions and MAN Diesel & Turbo are now aiming to reduce the size and weight of the same compression systems by at least 50%.

Aker Solutions chief technology officer Hervé Valla said: “We're proud to have played a leading part in developing this ground-breaking technology, which is proving its value as we now mark one year of strong operations since going on stream… We're taking this technology further to deliver slimmer and lower-cost compression systems without compromising on effectiveness.”

The intention is that a reduction in the size and weight of the compression system should result in lower overall investment and installation costs. However, MAN said to InnovOil that there were no plans to retrofit the existing template with smaller equipment, as far as it was aware.

MAN Diesel & Turbo’s oil and gas upstream head at Zurich, Basil Zweifel, said: “The next-generation of subsea compression systems will be based on proven technology and contribute to major improvements in both the recovery rate and lifetime for a number of gasfields. Aker Solutions and MAN will provide reliable compression systems for use at small subsea fields, as well as large deposits such as Åsgard.”

MAN remained vague on the details of when the tie-up would be available commercially, but did state: “The technology is so far developed that it will be applied to future subsea projects… The entire oil and gas industry has closely monitored the subsea technology progress in the past years. There is great interest and our subsea compression technology is being evaluated for current projects.”

https://www.youtube.com/watch?v=Ew1h9aU4odo