2/8-5

General

Well 2/8-5 is located within closure of the large NNW-SSE trending Valhall structure, close to well 2/8-2 and ca 8 km south of the 2/5-3 Sørøst Tor Discovery. The primary target was Danian/Maastrichtian chalk/limestones.

Operations and results

Exploration well 2/8-5 was spudded with the jack-up installation Zapata Explorer on 11 April 1974 and drilled to TD at 3304 m in the Early Cretaceous Rødby Formation. Some problems with lost circulation were experienced at 1618 m. At 1909 m in the Hordaland Group a gas kick was taken. Otherwise drilling went without significant problems.

No sand was encountered in Paleocene. The well penetrated 88 m of Danian chalk (Ekofisk Formation) and 380 m Late Cretaceous chalk (Tor Formation) before marls of the Rødby Formation were encountered at 3264 m. Well logs indicated that all target formations were water wet. Shows were reported as follows:

Miocene (1600 m to1722 m): white bright yellow amber fluorescence giving a fast yellow white slow cut. Associated with a gas peak on the chromatograph analysis at the top. Patchy fluorescence was recorded down section. Oligocene (1829 m): bleeding gas from limestone. (2353 m): pale yellow fluorescence, slow cut, with acid only. Eocene (2464 m to 2718 m): patchy shows, heavy brown oil stain, very dull amber to fast yellow fluorescence, occasional fast bright yellow cut, dark brown cut colour. The Shetland Group (2796 m to 3264 m): background gas only, maximum of 1.8% C1, trace C2-C4 at 3254 m. Fair oil stain, fair to good fluorescence and cut.

No conventional core was cut and no fluid sample taken. The well was permanently abandoned on 23 May 1974 as a well with oil shows.

Testing

No drill stem test was performed