Statoil: Lifetime of Oseberg Field Doubled (Norway)

The lifetime of the Oseberg field has doubled thanks to the steady increase in recoverable resources. December marks the 25th anniversary of the Oseberg field centre. Current plans call for production up to around 2040.

“The Oseberg licence has invested more than NOK 45 billion in the field over the last ten years. Excellent subsea work and use of new technology have contributed to a more than doubling of the recoverable reserves in the main reservoir on Oseberg, from 1.1 to 2.6 billion barrels of oil,” says Kjetil Hove, senior vice president for Operations North Sea east.

The original plan was for the field to produce until 2017. New drilling technology and extensive use of gas injection have made it possible to improve both the recovery rate and the expected lifetime of the field.

The development plans for the Oseberg field back in 1983 estimated the reserves at about one billion barrels of oil. Today, the estimated recoverable reserves in the main reservoir have increased to 2.6 billion barrels of oil. The field has already produced 1.7 billion barrels of oil to date.

“This has yielded enormous value creation for the owners and the Norwegian society and it will continue for many years to come”, Hove points out.

With a planned lifetime extending to around 2040, this means major ripple effects both in terms of jobs and for the supplier industry.

Extensive upgrades

The living quarters on the A platform have undergone a complete renovation in recent years. All of the 319 cabins have been rebuilt, and several break rooms, the control room, the laboratory and the galley have been replaced.

However, the most comprehensive upgrade is under way right now, on the Oseberg B drilling platform. Wells will be both overhauled and drilled, so the drilling facility has to be in good condition. The upgrade is scheduled to be complete in the spring 2014.

The installation has been in full operation while the upgrade work has been in progress; an effort which has demanded both a lot of personnel and top-notch planning.

The Oseberg licence has also undertaken the procurement of a Category J rig to ensure long-term rig capacity and reduced drilling costs. The rig will be used to drill additional wells on existing templates, to drill wells on new field developments, as well as to drill exploration wells. This is an important measure towards improving recovery from the field.

Award for increased recovery

The recovery rate for the main reservoir on the Oseberg field has reached a record-breaking 69 per cent. Statoil has an average recovery rate of 50 per cent on the Norwegian shelf, while the average recovery rate for the rest of the world is 35 per cent.

In 2012, Oseberg received the Norwegian Petroleum Directorate’s IOR (Increased Oil Recovery) award for its work to improve recovery through gas injection on the field. That same year, the company managed to replace the produced volume with new reserves in the area.

The Norwegian Petroleum Directorate estimates that gas injection has yielded more than 400 million barrels of extra oil from the field than would have been achieved with just water injection. This represents more than an entire new Veslefrikk field.