Production starts from Oseberg chalk

Offshore staff

OSLO, Norway --StatoilHydro has started production from a new well drilled into the Shetland Chalk formation in the Oseberg field in the Norwegian North Sea.

Since Oseberg started up in 1988, most attention has focused on the Brent sandstone formations. The Shetland Chalk, in the upper part of the field, was known to be oil and gas-bearing, but also more difficult to produce.

The company started drilling well B-24B from the Oseberg B platform this April, targeting a formation 20-30 m (66-98 ft) thick. Total length of the well is 5,050 m (16,568 ft), with a horizontal section 1,700 m (5,577 ft) long.

Following completion, the well was perforated by means of explosive charges at intervals of around 1 m (3.28 ft). Hydrochloric acid pumped into the well's 10 production zones reacts with the chalk, forming fissures extending over 50 m (164 ft), thereby increasing productivity.

Experience to date suggests the acid treatment has improved the formation's producing characteristics significantly. The crude is of a similar quality to Oseberg Brent. In the best case, StatoilHydro adds, this could lead to a drilling campaign prolonged for several years.

11/06/2007