3/7-1

General

Well 3/7-1 was drilled in the Søgne Basin in the North Sea, about 1400 m north of the border to Danish waters. The well location is near the top of a large anticline whose axis trends northwest with a 200 km2 closure at the pre-Zechstein horizon. The structure was considered as a north-western extension of the Fynn Falster High. The expected reservoirs were Danian and Maastrichtian chalky limestone, Jurassic sandstone, Rotliegend sandstone, and Carboniferous or Devonian sandstone. It was supposed that all or none of these reservoirs could be encountered. Basement could be found at different depths, owing to the difficulties in identifying main seismic horizons below the top of the chalky limestone.

Operations and results

Wildcat well 3/7-1 was spudded with the jack-up installation Ocean Tide on 1 August 1973 and drilled to TD at 3227 m, 9 m into basement rock.

The Paleocene and Maastrichtian horizons were encountered at 2690 m and 2852 m respectively, which was 41m and 28 m low to the geologic prognosis estimated depths. The basement (chloritic gneiss) was encountered directly underlying Turonian limestone.

Only the middle part of the chalky Maastrichtian section had some reservoir characteristics with inferred porosity from the BHC log about 12% from 2852 m to 2951 m and about l8% from 2951 to 2984.5 m. The Maastrichtian reservoir was water wet based on the IES log. The underlying Turonian - Campanian limestone was very tight. No hydrocarbon shows were reported from the well other than traces of dry gas.

One core was cut in basement at TD from 3221 - 3227 m. No fluid samples were obtained.

The well was permanently abandoned on 13 September 1973 as a dry well.

Testing

No drill stem test was performed.