15/2-1

General

Well 15/2-1 was drilled in the Vilje sub-basin in the Viking Graben in the North Sea, ca 1.5 km from the UK border.The objective of the well 15/2-1 was to test the Upper Jurassic, Middle Jurassic, and Triassic sandstone reservoirs northwest of and down dip of the salt diapir encountered in the well 15/5-3. The well was planned to be drilled ca 200 m into the Triassic with a total depth of ca 4525 m.

Operations and results

Wildcat well 15/2-1 was spudded with the semi-submersible installation Nortrym on 26 September 1981 and drilled to TD at 4600 m in the Late Permian Zechstein Group. No significant problems were encountered in the operations. The well was drilled with seawater and hi-vis pills down to 665 m and with Shaletrol polymer mud system from 665 m to 2750 m. At 2750 m the mud was converted to a dispersed mud system by adding lignosulphonate and this was used for the remaining well bore down to TD. There was 0 - 3% oil in the mud below 1168 m.

The well penetrated a number of sandstone Formations in the Tertiary (Skade, Grid, Intra Balder sandstone, Heimdal, and Ty Formations). All these were entirely water wet. The Hugin Formation (4356 - 4493 m) consisted of massive very fine grained sandstones with beds of coal on top. The Sleipner Formation (4493 - 4554.5 m) had a 10 m thick coal layer on top underlain by siltstones grading occasionally to very fine sandstones, interbeds of sandstones, and stringers of coal. The well did not penetrate any Early Jurassic or Triassic rocks, but encountered evaporites of Permian age at 4554.5 m, unconformably underlying the Sleipner Formation.

Good hydrocarbon shows were reported from both the Hugin and Sleipne