ID: 676
OBJECTID: 676
wlbNpdidWellbore: 1459
wlbName: 25/2-13
wlbHistory:

General

Well 25/2-13 was drilled in the central part of the Viking Graben, east of the Frigg area. The block straddles the eastern flank of the graben and the north-western part of the Utsira High. It was the first appraisal well on the 25/2-5 discovery, which discovered oil in different reservoirs of the Vestland Group and the Statfjord Formation. The structure is a north-south trending horst, which is located on a terrace in the southern part of the block. Well 25/2-13 was drilled close to a major normal fault bounding the structure. The main objective was to evaluate the western panel. The well should test the fluid columns in both the Vestland Group and the Statfjord Formation, obtain data for fluid characterisation and productivity, and try to define the hydrocarbon contacts of the reservoirs.

Operations and results

Appraisal well 25/2-13 was spudded 6 June 1989 by the semi-submersible installation West Vanguard drilled to TD at 3909 m in the Triassic Smith Bank Formation. The well was drilled to 13" 3/8 casing point (2043 m) without problems, but at 2178 m the bit got stuck and a sidetrack was needed. The sidetrack was kicked off from 2070 m. The first attempt failed, but the second was successful. During coring of the Vestland Group, the core barrel was lost in hole and a second sidetrack was decided after unsuccessful fishing. This sidetrack was kicked off from 3306. The mud that was used in the Jurassic section (3318 - 3887 m) was an FCL type mud which was based on fresh water with added bentonite, polymers, lignosulfonate and barite.

Top Vestland Group came in at 3342 m as prognosed, and with mobile hydrocarbons in two layers; oil in the top ca 40 - 60 m of the reservoir with an unclear OWC in the interval 3382 - 3415 m, a
wlbHistoryDateUpdated: 2020-02-21T00:00:00