30/3-1 R

General

Well 30/3-1 R is located just north of the Huldra Discovery. The primary well bore 30/3-1 was drilled in 1979 to a total depth of 3718 m where it was suspended due to an unexpected pressure build-up in the Early Cretaceous. The purpose of well 30/3-1 R was to re-enter the previously abandoned well and continue drilling beneath the 9 5/8" casing shoe to test sandstones in the Brent Group. Secondary objectives were sandstones in the Early Jurassic, Cook and Statfjord formations. Well 30/3-1 R (Phase 2) was planned to be drilled 50 m into the Triassic to a total prognosed depth of 4825 m.

Operations and results

Wildcat well 30/3-1 R was re-entered by the semi-submersible installation Dyvi Delta on 1 January 1982 and drilled to TD at 4421 m (4395 m TVD) in Late Triassic sediments in the Statfjord Formation. After the 9 5/8" casing had been drilled and cleaned out for cement plugs the string was lost in the hole when running in with a new bit. After several attempts to retrieve the fish, the hole was plugged back. A window was cut in the 9 5/8" casing from 3657 m to 3672 m and the hole was kicked off from this depth after problems with lost circulation had been solved. While drilling of the last part of the 8 1/2" hole several incidents of stuck pipe was experienced. This section was plugged back with cement. When displacing the second cement plug, the pipe got stuck. After cutting the 5" drill pipe an influx (gas and water) from the top of the Statfjord Formation was taken. The well built a deviation with maximum of 20.5° at 4165 m. The well was drilled with a Spersene XP 20/Magcogel/nut plug mud system from kick-off to TD.

Hydrocarbons were encountered in thin sandstones interbedded with limestone, coals and claystones over the interval from 3762 m to 3861 m in the Ness, Etive, and Rannoch formations in the Brent group. One core was cut from 3863.6 m to 3875.2 m in the Brent Group. No fluid sample w