30/6-5

General

Well 30/6-5 was drilled on the Brage Horst east of the Gullfaks fault block in the North Sea. The main purpose was to test the hydrocarbon potential in Middle Jurassic sandstone.

Operations and results

Wildcat well 30/6-5 was spudded with the semi-submersible installation Deepsea Saga on 11 June 1981 and drilled to TD at 3550 m in the Triassic Lunde Formation. No significant problem was encountered in the operations. The well was drilled with spud mud down to 951 m, with gypsum/polymer mud from 951 m to 1801 m, and with gel/lignosulphonate mud from 1801 m to TD.

The Brent Group, Tarbert Formation was encountered at 2824 m. From wire line logs and petrophysical analysis oil was found from 2841 m down to 2899 m. Pressure measurements indicated oil/water contact at 2907 m. Shows on cores continued down to 2933 m. The Etive Formation represented the main part of the net pay.

Eight cores were cut in the well. Cores 1 and 2 were cut in the interval 2843.5 - 2854.7 m. Cores 3 to 8 were cut in the interval 2871.5 - 2949.8 m. RFT oil samples were taken at 2847.5 m, 2867.1 m (film of oil), 2871.2 m (traces of oil), 2874.5 m, 2881 m, 2889 m, 2923 m (film of oil). The samples proved H2S contents in the range 30 - 50 ppm.

The well was permanently abandoned on 15 August 1981 as an oil discovery.

Testing

The rig lacked qualified equipment and personnel trained for drill stem testing with the levels of H2S proven by RFT sampling. Testing was therefore abandoned.