6407/10-1

General

Block 6407/10 is an oil prone part of the Halten Terrace. Well 6407/10-1 is located immediately to the south of the Njord Field in block 6407/7, on compartment B1 of the B-structure. The B-structure is down faulted relative to the Frøya High in south-southeast and to the A-structure in block 6407/7 to the west. The structure is dipping into a small, deep basin to the north. The main objectives of the well were to test hydrocarbon potential of the Garn, Ile and Ti1je Formations in the B-structure. Further objectives were to test the geological model and to calibrate the seismic interpretation and horizon identification. The well location was chosen to penetrate the target reservoir with an up-dip of less than 15-30x10 6 sm3 oil in place, and to penetrate the Tilje Formation within the expected depth range of the oil-water contact in the Ti1je Formations in the A-structure.

Operations and results

Wildcat well 6407/10-1 was spudded 7 may 1987 by Polar Frontier Drilling semi-submersible rig Polar Pioneer and drilled to TD at 3347 m in the Triassic Grey Beds. Due to a shallow gas risk, the well was drilled without riser and logged with MWD down to 1100 m. The prognosed shallow gas levels were drilled without problems and only small peaks on the log indicated sand with a certain gas saturation. The 20" casing was skipped and 13 3/8" casing was set directly. The well was drilled with seawater and hi-vis pills down to 1117 m and with KCl mud from 1117 m to TD.

The well was water bearing with a possible small amount of gas in the upper part of Ti1je Fm. Some shows were recorded in the Ile Formation. The Formation pressures encountered showed that the A and B compartments of the Njord Field are not in communication. Five cores were cut in the intervals 2582 - 2610 m (Rogn Formation), 2748 - 2776 m (Not Formation), 2817 - 2845 m (Ile Formation), 2845.5 - 2873.5 m (Ile / Ror Formation), and 2983 - 3011 m (Tilje Formation).<