6407/12-3

General

Well 6407/12-3 was drilled on the Caerus prospect in the Froan Basin, ca 4 km east of the southern end of the Draugen Field in the Norwegian Sea. The primary objective was to evaluate the hydrocarbon potential in the Late Jurassic Rogn Formation within the license PL 470. Secondary objective was to check for hydrocarbon presence in the Middle Jurassic Garn and Ile Formations.

Operations and results

Wildcat well 6407/12-3 was spudded with the semi-submersible installation West Alpha on 14 May 2010. Drilling started with a pilot hole down to 1080 m to confirm no shallow gas. The pilot was opened up with 36" and 26" hole openers and further drilling commenced without significant problems to TD at 1968 m in the Middle Jurassic Ile Formation. The well was drilled with seawater and hi-vis sweeps down to 1080 m and with KCl/Glydril WBM from 1080 m to TD.

The expected thin section of the Shetland Group was missing. Based on biostratigraphic analyses the formation changes directly from the Tertiary Tang Formation to the Early Cretaceous Lange Formation. Top Viking Group, Spekk Formation was encountered at 1629.5 m. The primary prospect Rogn Formation, an intra-Spekk deposit, was not seen. However, biostratigraphic analyses suggested a shaly time equivalent deposition might exist. The secondary prospect, the Garn Formation did not come in as prognosed, instead an intra-Melke Formation (according to biostratigraphy) sandstone deposition was encountered at the prognosed depth for the Garn Sandstone, from 1781 to 1816 m. The Garn Formation came in deeper, from 1828 to 1890 m. This was however a very shaly deposits with only minor sandstone beds. This is also known from some other wells in the area, but no wells have the thickne