35/9-7

General

Well 35/9-7 was drilled on the Skarfjell prospect on the Ryggsteinen Ridge, about 17 kilometres southwest of the Gjøa field in the North Sea. The purpose of the well was to prove petroleum in Late Jurassic reservoir rock.

Operations and results

Wildcat well 35/9-7was spudded with the semi-submersible installation Songa Delta on 28 February 2012 and drilled to TD at 3006 m in the Middle Jurassic Rannoch Formation. No significant problem was encountered in the operations. The well was drilled with spud mud down to 600 m and with Aquadril mud from 600 m to TD.

Two Intra Heather Formation Sandstones were penetrated: an Oxfordian age sandstone at 2621 m to 2690 m (Intra Heather Sandstone 2) and a Bathonian-Callovian age sandstone at 2776 m to 2790 m (Intra Heather Sandstone 1). The total net reservoir in the two sandstone intervals is 54.2 m. Both reservoirs were filled with light oil in oil down-to settings. The densities of the oils are slightly different but the two columns fall on a common pressure gradient within one bar discrepancy. The overpressure at top reservoir is 16.7 bar. The Sandstones in the Brent Group were found water bearing with a hydrostatic pressure gradient.

Three cores were cut from core point 2628 m in the Intra Heather Sandstone 2 to 2706 m the underlying Heather Formation shales. The Intra Heather Sandstone 1 was not cored. Twelve single phase samples were acquired. Seven oil samples were collected from the Intra Heather Sandstone 2, at depths 2626.2 m, 2635.2 m, 2664.1 m, and 2687.7 m; four oil samples were collected from the Intra Heather Sandstone 1 at depths 2776.7 m and 2783.7 m; and one water sample was collected from the Etive Formation at 2968