7/8-2

The 7/8-2 (Cero) well was drilled on a domal structure approximately 6 km long by 6 km wide, situated on the Jæren High in the North Sea. It was estimated that at Paleocene depth there would be close to 40 square km of closure with 140 m of vertical relief and at Early Cretaceous depth 27 square km of closure with 150 m of vertical relief. The principal objective horizons were Paleocene, Jurassic and Triassic sands with the Danian-Cretaceous limestone as a possible secondary objective.

Operations and results

Wildcat well 7/8-2 was spudded with the semi-submersible installation Ocean Viking on 24 July 1973 and drilled to TD at 3006 m in anhydrite of the Zechstein Group. No significant problems are reported from the operations.

The well had no hydrocarbons or shows of hydrocarbons. In the Paleocene no sand beds were developed, although sand was present as a loose, unconsolidated constituent in most of the clays and shales. The Danian and Late Cretaceous limestones were tight. The Late Cretaceous section was 150 m thinner than anticipated due to erosion of the Coniacian to Cenomanian formations at the base. The Jurassic succession was encountered at 2808 m and top Triassic at 2883 m. Two Triassic sands were encountered at 2911 - 2937 m and at 2972 - 2996 m. The Triassic section was thinner than expected, being truncated at 2996 by the Permian Zechstein Group.

No cores were cut and no wire line fluid samples were taken in the well.

The well was permanently abandoned on 29 August 1973 as a dry well.

Testing

No drill stem test was performed.