30/11-9 A

General

Well 30/11-9 A is a geologic sidetrack to well 30/11-9 S. It was drilled to test the Askja East prospect in the Fensal Sub-basin, about 35 km south of the Oseberg Sør installation in the North Sea. The Askja East prospect is situated in a separate fault block to the 30/11-9 S Askja West discovery.The primary objective for 30/9-11 A was to prove petroleum in the Middle Jurassic Tarbert Formation. The secondary exploration target was to prove petroleum in reservoir rocks in the Middle Jurassic Ness and Etive formations.

Operations and results

Wildcat well 30/11-9 A was kicked off at 1401 m in main well 30/11-9 S on 13 November 2013. It was drilled with the semi-submersible installation Ocean Vanguard to TD at 4054 m in the Middle Jurassic Ness Formation. Problems with the Ocean Vanguard DDM caused some downtime and slow drilling in periods, but otherwise no significant problem was encountered in the operations. The well was drilled with XP-07 oil based mud from kick-off to TD.

The top of the expected main reservoir, Tarbert Formation came in as prognosed at 3615 m (3252 m TVD). Based on pressure gradients and fluid sampling, oil was present in two differently pressured compartments within the upper part of the Tarbert Formation. The upper reservoir contained oil from 3615 m (3252 m TVD) down to an oil-water contact indicated at 3636 m (3272 m TVD). The lower reservoir contained oil from 3745 m (3374.5 m TVD) down to an oil-water contact indicated at 3771 m (3400 m TVD). Oil shows (fluorescence) were described on sandstones in between these two reservoirs. The lower part of Tarbert Formation and the Ness Formation were water bearing. The Etive Formation was not drilled since the Ness Formation was wate