35/11-11

General

Well 35/11-11 is located east of the Fram Field and ca 17 km North of the Troll Field. The main objective for well 35/11-11 was to appraise the eastward extension of the Oxfordian Turbidites (Intra Heather Sandstone unit), in the H-East compartment of the Fram Field. Oil and gas were encountered in the discovery well 35/11-8 S and the extension toward the south was confirmed by the drilling of well 35/11-9, which encountered good reservoir quality and pressure communication between the two wells. Possible hydrocarbons in the Brent Group was a secondary objective, although the well was expected to penetrate the Brent Group in a down flank position below the OWC. A third objective was Paleocene sands to assess the reservoir- and production properties as a source for make-up water. This interval was supposed to be penetrated close to a high amplitude reflector and the presence of hydrocarbons could not be excluded.

Operations and results

Wildcat well 35/11-11 was spudded with the semi-submersible installation Transocean Leader on 16 April 1998 and drilled to TD at 3225 m in the Early Jurassic Drake Formation. Operations went without significant problems. The well was drilled with spud mud down to 1253 m and with AQUACOL/KCl/polymer mud and freshwater from 1253 m to TD. AQUACOL is a glycol mud system.

Two sands equivalent to the Heimdal and Ty Formations were encountered in the Paleocene. Both were water wet. A total of 119 m gross Late Jurassic reservoir sequence was penetrated in well 35/11-11 on the H East Structure. All massive sands have been interpreted as three individual turbidite deposits of Kimmeridgian/Volgian (Intra Draupne Sand), Oxfordian (Intra Heather Sand) and Callovian (Intra Heather Sand) age respectively. Oil shows were recorded on sandstones and siltstones throughout Late Jurassic, but all main target reservoirs were found water bearing and not in pressure communication with the H Structure. In the Brent G