7/7-3

Well 7/7-3 is located ca 5 km east of the UK border on the Jæren High in the North Sea. It was drilled to appraise the Late Jurassic discovery in well 7/7-2 and was designed to test seismic interpretations, reservoir thickness and properties, pressure regime, and volume of recoverable oil. The well was planned as a future injector, but since the reservoir only indicated traces of hydrocarbons it was permanently plugged.

Operations and results

Well 7/7-3 was spudded with the semi-submersible installation Deepsea Bergen on 20 April 1993 and drilled to TD at 3584 m in the Late Permian Zechstein Group. The well took 17 days more than planned to drill, mainly due to a 8,5 days downtime related to BOP repair and loss of circulation at end of 12 1/4" section. The well was drilled with seawater and hi-vis pills down to 918 m, and with ANCO 2000 mud from 918 m to 2677 m. From 2677 m to 3354 m the mud was gradually displaced to an ANCOTHERM/Bentonite system. The ANCOTHERM/Bentonite system was used from 3354 m to TD.

The 7/7-3 well penetrated the Ula Formation at 3490.5 m. The siltstone and the uppermost 2 metres of the sandstone showed only weak shows and the following logging and evaluation confirmed that the sandstone did not contain any moveable hydrocarbons.

Three cores were cut from 3486 m to 3516 m, from base Farsund Formation, through the Ula Formation and into the Triassic Group. Two segregated FMT fluid samples were taken at the same depth, 3497.3 m. All fluid chambers proved to contain mud filtrate and water and did not contain any hydrocarbons.

The well was permanently abandoned on 4 July 1993 as dry with shows.

Testing

No drill stem test was performed