NPD Spotlights Åsgard Subsea Compression Technology

The Norwegian Petroleum Directorate (NPD) has awarded its improved oil recovery (IOR) prize for 2016 to the licensees of the Åsgard field in the Norwegian Sea for their subsea wet gas compressor.

This will yield almost 50 million standard cubic metres (306 million barrels of oil equivalent) in additional gas and condensate.

The Åsgard licensees are Statoil (operator with 34.57 per cent), Petoro (35.69), Eni (14.82), Total (7.68) and ExxonMobil (7.24).

Operational from October 6, 2015, the compressor is the first of its kind in the world. It stands in 300 metres of water and covers an area similar to a football pitch. Gas is recovered from reservoirs 2 500 metres beneath the seabed.

The idea was born more than 20 years ago. Testing of subsea installations on Draugen, Troll, Tordis and Tyrihans in 1994-2009 were necessary moves towards the realisation of this step-changing technology.

Åsgard Subsea Compression Ribbon-Cutting Ceremony

Aker Solutions, in December 2010, was awarded the contract by Statoil to deliver the system, which consists of modules for two identical sets of compressors, pumps, scrubbers and coolers fitted together in an 1,800-metric ton steel frame.

Its development was pursued in a close and trusting collaboration between the oil companies and a number of suppliers who have competed for the contracts.

“Achieving such interaction is perhaps especially important today,” NPD director general Bente Nyland observed when presenting the prize during the opening ceremony for the ONS 2016 exhibition and conference in Stavanger. “So is keeping world-class, dynamic engineering clusters.”

The Åsgard subsea compression technology is expected to yield 49 million scm in additional gas and condensate from the Midgard and Mikkel reservoirs. The recovery factor is expected to rise from 71 to 86 per cent for the former, and from 46 to 68 per cent for the latter.

This technology project has been demanding. Statoil began testing in the K-lab at Kårstø as early as 2008, when it tried out a full-scale model under water. The most important qualification areas have been power supply for the compressors, the compressor motors and the control systems. Development of the installations system for the modules has also been a key area.