ID: 363
OBJECTID: 363
wlbNpdidWellbore: 368
wlbName: 25/11-7
wlbHistory:

General

Well 25/11-7 was drilled ca 3 km west-south west of the 25/11-1 Balder discovery well on the Utsira High in the North Sea. The primary objective was to delineate topographic mounds developed in the Paleocene sands of the Balder Field. The primary targets were the Zone II sand (E-70 sand) which was found oil-bearing in the 25/11-5 and the Zone I-B sands which were found oil-bearing in the 25/11-6.

Operations and results

Appraisal well 25/11-7 was spudded with the semi-submersible installation Norskald on 3 October 1978 and drilled to TD at 1944 m in the Late Cretaceous Tor Formation. The well was drilled with Seawater/Gel/Lignosulphonate.

The well penetrated the Utsira Formation and several Skade Formation sands and then penetrated a ca 600 m thick section of shales belonging to the lower Hordaland Group before top Balder Formation was encountered at 1697 m. The Balder Formation contained some shaley sands with poor to no oil shows. The massive I-B sand at 1750.3 m (Heimdal Formation) was the only significant oil sand in the well. The well proved 36 m of net oil sand with a clear oil-water contact at 1786.5 m (1761.5 m MSL), in reasonable agreement with the Balder Field contact at 1760 m MSL established in 25/11-6. The Zone II (E-70) sand was absent, or possibly an unrecognizable part of the I-B Sand.

A total of 20.35 m core was recovered in four cores from the interval 1748.6 to 1772.3 m in the Lista and Heimdal Formations. No wire line fluid samples were taken.

The well was permanently abandoned on 27 October 1978 as an oil appraisal well.

Testing

wlbHistoryDateUpdated: 2016-07-06T00:00:00