6506/11-4 S

General

Well 6506/11-4 S was drilled on the southern segment of the Smørbukk Discovery. The objectives of the well were to appraise the Smørbukk Discovery and to verify the planned production in the southern segment. The well was planned to be completed as a future producer.

Operations and results

Wildcat well 6506/11-4 S was spudded with the semi-submersible installation Transocean Searcher on 11 February 1996 and drilled to TD at 5110 m (4887.5 m MSL) in Early Jurassic sediments of the Åre Formation. The hole was drilled to 4531 m in the Garn Formation and the 9 5/8" casing was set at planned depth, with casing shoe a few meters into the Garn Formation. However, during drilling out of casing, the new 8 1/2" bottom hole assembly was seized by late setting cement and got stuck inside casing. The well was side tracked with KOP at approximately 3144 m. The sidetrack is designated 6506/11-4 S T2. The sidetrack leg was drilled to the original target zone, the Åre Formation. The well was drilled with seawater and bentonite down to 1415 m, with KCl/polymer/Anco200 from 1415 m to 2825 m and with Ancovert oil based mud from 2825 m to TD.

A Lange Formation sandstone unit was encountered from 4236 m to 4321 m. Well bore 6506/11-4 S T2 penetrated the top of the Tilje Formation and the Åre Formation approximately 24 m deeper than prognosed. Logs proved hydrocarbons in the Garn Formation, the Ile Formation and in the Åre 2 reservoir zone. The Tilje 1.1 Reservoir Zone was found to be water bearing. Hydrocarbons were further indicated by high resistivity log readings in the Lange Formation sandstone unit and in interbedded sandstones in the Lysing Formation from 3571 m to 3603 m.

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