25/2-15

General

Well 25/2-15 is located in the southern part of block 25/2, and was designed to recognize the petroleum potential of the so-called Jurassic Prospect 1. The main objective of the well was to explore the Middle Jurassic Brent sandstones. An optional objective was Early Jurassic Statfjord sandstones, depending on the petroleum results at the Brent level.

Operations and results

Wildcat well 25/2-15 was spudded with the semi-submersible installation West Alpha on 14 November 1992 and drilled to TD at 3505 m in Middle Jurassic sediments of the Heather Formation.

After drilling to TD at 3505 m in the 12 1/4" section the drill string was hung off with bit at 13 3/8" casing shoe, due to bad weather. A long period of bad weather followed with a total of 170 hours WOW. On 13 January 1993, when reaming up the hole to set 9 5/8" casing, a fire broke out in the port side engine room. As a consequence of this three anchor chains were lost and the rig started to drift. The drill string was sheared and the LMRP was disconnected. All unnecessary personnel were evacuated. The situation was brought under control, but due to the damage occurring in engine room, it was decided to substitute the rig, pull anchors and move the rig to Haugesund fjord. The well was drilled with seawater and hi-vis bentonite sweeps down to 198 m, with bentonite mud from 198 m to 1150 m, and with gypsum polymer mud treated with 5% polyglycerol from 1150 m to 3505 m.

All geological results from the well are given in the 25/2-15 R2 history.

The well was suspended with the drill string fallen in the hole and shear rams closed. The hole was full of 1.27 SG mud. West Alpha left location on 19 January 1993.

Testing

No drill stem test was performed in the well.