35/3-7 S

General

Well 35/3-7 S was drilled on the Cyclops prospect close to the Agat Discovery on the Måløy Slope in the Northern North Sea. The objective was to prove hydrocarbons in the Agat Formation (Agat 70 and Agat 80 sandstone units).

Operations and results

Wildcat well 35/3-7 S was spudded with the semi-submersible installation Bredford Dolphin on 28 June 2009 and drilled to TD at 4051 m in the Late Jurassic Heather Formation. A 9 5/8" pilot hole was drilled from 550 m down to 836 m. A water flow incident happened at 745 m. This was expected from previous wells in the area and a Riserless Mud Recovery system (RMR) was utilized to use weighted mud from seabed. By this the water flow was taken care of in a controlled manner. When setting the 9 5/8" liner the liner was lost in the well, but it was finally cemented and successfully tested 2.0 sg EMW. Due to a stuck pipe incident on a wiper trip between wire line logging runs a technical sidetrack had to be drilled to fulfil the formation evaluation program. The sidetrack was kicked off at 3248 m, below the 9 5/8" casing shoe, and reached TD at 3777 m, ca 110 m south of the primary well bore. The well took 95.8 days vs. 61.2 days planned. The additional days were mainly caused by the lost 9 5/8" liner, the stuck pipe incident including sidetrack and 10.2 days waiting on weather before pulling anchors. The entire main well bore was drilled with KCl/GEM water based mud (WBM) and the sidetrack was drilled with Performadril WBM.

The combined results of the main bore and the sidetrack was a gas discovery in the Agat formation in the Lower Cretaceous as proven by pressure data and gas samples. The pressure data combined define a GWC at 3652 m (3573 m TVD RKB, 3548 m TVD MSL)