Grenland bags contract to modify Oseberg

On behalf of the Oseberg licence partners, Hydro has awarded the Grenland Group a NOK 600 million plus contract for modification work on the Oseberg Field Centre. The modifications will enable the production of more oil from wells with low reservoir pressure.

After 18 years of oil production, and six years of gas exports from the Oseberg Field Centre, pressure in the Oseberg reservoirs has declined. By modifying the processing facility Hydro will be in a position to decrease the intake pressure for the oil coming up to the Centre.

Oil and gas have always been taken in at first-phase separators on Oseberg B. The first-phase separators currently have a pressure of 67 bar, but the processing facility will now be modified so that the oil can go right into the second-phase separators, where the pressure is lower, at 20 bar. Since production on the Oseberg Field Centre started in December 1988, reservoir pressure has fallen by 70 bar to 100 bar.

Up to 10 wells will be adapted into second phase separators. Start-up of low-pressure production is expected in the autumn of 2009, and the contract period will run right up to spring 2010, when the facility will be completed.

The modification project is very extensive and complex, and involves work on two platforms. The contract with the Grenland Group involves engineering, procurement, construction and installation.

The work consists of installing low-pressure flow pipes and new low-pressure manifolds on Oseberg B, as well as the installation of pipes from the low-pressure manifolds on Oseberg B over bridge to Oseberg A, where the pipes will be connected to the Oseberg A second- phase separators.