Statoil alters Statfjord oil/gas equation

Offshore staff

STAVANGER -- Statoil has commemorated 30 years of production from its giant Statfjord field in the Norwegian North Sea. This has long been one of the company’s main oil producers, but following implementation of the Statfjord late life project, 65% of its current output is gas.

The program involved a series of facility modifications to prepare Statfjord’s three platforms for production of gas and oil at lower pressure. For years, the focus was on sustaining pressure in the reservoir to eke out as much oil as possible. Today, the emphasis is on lowering reservoir pressure to extract further quantities of gas.

This process, recently under way in reservoirs 2.5 km (1.55 mi) beneath the platforms, causes the gas to bubble out of the remaining oil volumes.

Statoil says that over the past three decades, Statfjord has generated 4 Bboe. It now aims to lift the rate of recovery from the field to 66% for oil and 71% for gas. In time, similar depressurization schemes may be applied to other giant Norwegian fields such as Gullfaks and Oseberg.

At the Hammerfest LNG plant in northern Norway, however, operations remain suspended due to the need to replace a faulty electric motor that forms part of the cooling process. The plant is supplied with gas from the Snohvit field in the Barents Sea.

11/25/2009