35/3-6

General

Block 35/3 is located where the Måløy Terrace continues into the Selje High. The Selje High has a NE/SW trend, whereas the MåIøy Terrace is dominated by a N-S fault trend.

The objectives of well 35/3-6 were to test for commercial hydrocarbons and locate any associated hydrocarbon contacts within the Måke Nord prospect, to investigate the Albian Agat Formation, and to obtain and evaluate data required for any potential appraisal drilling.

Operations and results

The exploration well 35/3-6 was spudded on 6 February 2002 with the semi-submersible installation Deepsea Bergen and drilled to a total depth of 3366 m in the late Jurassic Heather Formation. The 36" section was drilled with seawater and swept with high viscosity pills. The 9-7/8" pilot hole was drilled riser-less with seawater and high viscosity pills and displaced to 1.20 sg mud. This hole was then opened to 17 1/2" with seawater and high viscosity pills and displaced to 1.20 sg mud prior to running the 13 3/8" casing. The 12 1/4" section to TD was drilled with KCl/polymer/glycol mud (Glydril). When drilling the 36" section, a boulder bed was experienced from 270m to 275m (22 m to 27 m below seabed). This led to hole inclination going up from 1 to 3.5 degrees. After setting the 13 3/8" casing, the wellhead was inspected with the ROV and a flow was observed from below the guide base, which was partially covered by debris. After an unsuccessful attempt to stop the flow by grouting the 30" conductor and landing the BOP, a combined cement bond log and temperature log were then run. It was concluded that the water-flow originated from the Utsira Formation sands below 587 m. A bridge plug was set, the casing perforated at 568 m and a cement retainer installed. By repeated injection and partially circulation of kill mud through the perforations, the well was stabilized. A combination of a cross-linked polymer pill and low-density