30/8-2

General

Well 30/8-2 was drilled in the Viking Graben of the North Sea, about mid-way between the Hild and the Oseberg Sør Fields. The objective was to test the hydrocarbon potential of the Tertiary X1 prospect. The main target was a prognosed Heimdal Formation sand within the Lista Formation. Planned TD was at 2404 m in the uppermost Cretaceous.

Operations and results

Wildcat well 30/8-2 was spudded with the semi-submersible installation West Vanguard on 15 December 1995 and drilled to TD at 2405 m in the Late Cretaceous Jorsalfare Formation. Indications of shallow gas was observed as low gamma and high resistivity in a thin sand layer at 386 m. No significant problems were encountered in the operations. The well was drilled with spud mud down to 1542 m and with KCl/polymer mud from 1542 m to TD.

The prognosed Heimdal Formation was not present in the well but a sandstone rich interval assigned to the Hermod Formation was encountered. In the Hermod Formation, a total of 31 m net reservoir sand was calculated between 2075.5 m and 2137.5 m. A Petroleum Geochemistry Study of the reservoir interval indicated significant amounts of migrated hydrocarbons in the Hermod Formation. Traces of migrated hydrocarbons were detected also in thinner sands in the Balder and Våle Formations. The reservoir properties were excellent. An average porosity of approximately 30% has been calculated based on petrophysical evaluation. Permeabilities greater than 3500 mD are measured from core plugs. The hydrocarbon saturation is low and no evidence for moveable hydrocarbons was found in the log data. Fair to weak shows were recorded on cuttings from sandstones and limestone stringers from Top Balder Formation to TD, and good oil shows were recorded on sandston