1/6-2

General

Well 1/6-2 was drilled between the Albuskjell and Flyndre Fields in the Feda Graben of the North Sea. The primary objective was to evaluate the Danian and Maastrichtian Chalk prospects (Ekofisk and Tor Formations) of a prominent diapiric domal structure. The well was placed on the flank of the structure.

Operations and results

Wildcat well 1/6-2 was spudded with the jack-up installation Zapata Nordic on 28 November 1972 and drilled to TD at 3383 m in the Late Cretaceous Hod Formation. Some downtime recorded in the top hole was due to a defect 20" casing shoe and bad weather, otherwise operations went forth without significant problems. The maximum deviation down to 3226.6 m was 3.5 deg. The well was drilled with Sea water and viscous mud down to 460 m, with Shaletrol mud from 460 m to 2445 m, and with Unical mud from 2445 m to TD.

In the Tertiary shale sequence potential reservoirs were limited to a few very thin (0.5 m or less) limestone or dolomite streaks. Top of the Chalk was encountered at 3024 m. The reservoir development in the Chalk was rather poor throughout, with the exception of a zone of ca 12 m in the Danian Ekofisk Formation having a porosity of about 26%. The Chalk formations were entirely water bearing as seen on the logs. However, weak hydrocarbon indications were observed in the Chalk (namely weak fluorescence and occasional slight oil staining), and relatively more abundant indications of oil staining and dead oil traces were recorded in the overlying Tertiary shales and interbedded carbonate layers.

One core was cut from 3226.6 m to 3241.5 m in the Tor Formation. The core confirmed the generally dense nature of the Chalk in this section. No wire line