ID: 208
OBJECTID: 208
wlbNpdidWellbore: 213
wlbName: 25/11-9
wlbHistory:

General

Well 25/11-9 was drilled ca km west-south west of the 25/11-1 Balder discovery well on the Utsira High in the North Sea. The objective was to establish the presence of a thick accumulation of oil sand in the southern part of the Balder Field, and to confirm the reservoir quality of Lobe 8 penetrated in the 25/11-5 well. The top of the reservoir was anticipated to be at 1688 m subsea.

Operations and results

Appraisal well 25/11-9 was spudded with the semi-submersible installation Norskald on 4 November 1980 and drilled to TD at 1910 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 560 m thick section of shale/mudstone/siltstone belonging to the lower Hordaland Group before top Balder Formation was encountered at 1670 m. Drilling revealed two oil sand zones, one of Eocene age between 1708.5 m and 1742 m (Intra Balder Formation sand), the second of Paleocene age (Hermod Formation) between 1781 m and 1785 m, which is the Balder Field oil-water contact. A few thin sands in the upper Balder Formation from 1671 m to1694 m also appeared to be oil bearing. A second Hermod Formation from 1789 to 1818 m was water wet with some weak shows.

Four conventional cores were attempted in the interval 1718 to 1744 m in the Intra Balder Formation Sandstone, but only 3.5 m from the first and 1.5 m from the last core was retrieved. No wire line fluid samples were taken.

The well was permanently abandoned on 7 December 1980 as an oil appraisal well.

wlbHistoryDateUpdated: 2016-05-19T00:00:00