ID: 938
OBJECTID: 938
wlbNpdidWellbore: 2733
wlbName: 34/11-2 S
wlbHistory:

General

Well 34/11-2 S was drilled on the Tjalve Terrace east of the Gullfaks Field in the northern North Sea. The main objective was to explore the hydrocarbon potential of the Middle Jurassic Brent Group reservoirs within the Beta structure. The secondary objective was to test for hydrocarbons in the Lower Jurassic/Triassic Statfjord Formation.

Operations and results

Wildcat well 34/11-2 S was spudded with the semi-submersible installation Vildcat Explorer on 16 January 1996 and drilled to TD at 4743 m in the Early Jurassic Statfjord Formation. The well was drilled practically vertical down to ca 3139 m, ca 140 m below the 13 3/8" casing shoe, and deviated from this point. The drilling of the well was not performed within the plan due to lost time as a consequence of bad weather, steering and building angle in 12 1/4" hole section, extended logging, extended well and equipment failure. The well was drilled with pre-hydrated bentonite, seawater and bentonite sweeps down to 1170 m, with ANCO 2000 mud with 3.4 to 5.2% glycol from 1170 m to 3766 m, and with a KCl/polymer mud system from 3766 m to TD.

Oil was proven by MDT fluid sampling in a thin sand bed at 3797.5 m (3756.2 m TVD) above the main Brent Group reservoir. The Bathonian age of these sand beds imply that they belong to the upper part of the Brent Group. Sliding or faulting of huge blocks along the foot wall of the main fault could explain the presence of this Allochtonous "Brent Group" above the Heather Formation. Top of the main objective the Brent Group was penetrated at 4068.0 m

(3422.1 m TVD), 252 m deeper than the prognosis. Pressure measurements indicated hydrocarbon fluids present in the entire
wlbHistoryDateUpdated: 2016-07-06T00:00:00