7125/1-1

General

Well 7125/1-1 was drilled in the Lopparyggen East area on the southern end of the Bjarmeland Platform towards the Nyslepp Fault Complex. The primary purpose of the well was to test for hydrocarbons in the Late Triassic/Early Jurassic sandstones of the Kapp Toscana Group. These were found hydrocarbon bearing in well 7124/3-1. A secondary objective was to test for hydrocarbons in the underlying Middle Triassic Kobbe Formation. In well 7124/3-1 weak oil shows were seen in sands from this formation.

Operations and results

Wildcat well 7125/1-1 was spudded with the semi-submersible installation Ross Rig 30 November 1988 and drilled to TD at 2200 m in Triassic rocks. Drilling proceeded without significant problems. The well was drilled with spud mud down to 818 m and with KCl / polymer mud from 818 m to TD.

There was no indication of shallow gas in the hole. The well proved a significant reservoir development in the Kapp Toscana Group where 130 m sandstone with good reservoir properties was indicated. Top of Kapp Toscana Group, Stø Formation, was encountered at 1399 m. Logs and RFT showed a thin oil zone of 1 - 1.5 m from 1403.5 - 1405 m. Oil shows were seen from 1402.5 m down to 1435 m in sandstones. In the interval 1405 -2200 pressure point measurements show a gradient of 1.14 SG, which indicate saline formation water. The Triassic Kobbe Formation was encountered at 2104.5 m. Gas was encountered in two thin sand intervals in the top of the Kobbe Formation. The upper sand interval (2105.1 m to 2107.8 m) has an average log porosity of 19 % and an average water saturation of 49 %. In the lower sand (2123.5 m to 2125.3 m) the corresponding values are 20.5 and 53, respectively. Gas shows and weak oil shows were observed in thin sand intervals down to 2140 m. One core was taken in the Hekkingen Formation cap rock from 1360 to 1371 m. A second core was taken in the Stø reservoir sandstone from 1406 m to 1434 m. A total of thre