ID: 529
OBJECTID: 529
wlbNpdidWellbore: 871
wlbName: 6407/9-6
wlbHistory:

General

Well 6407/9-6 was drilled on the Draugen Field in the Haltenbanken area off shore Mid Norway. The target was the Rogn Sandstone Formation of the Late Jurassic. The objectives were to identify the western edge of the Rogn

Formation, to establish the reservoir properties and development of the basal shale, to evaluate the water injection potential in oil-bearing sand, and to calibrate the seismic velocity.

Operations and results

Appraisal well 6407/9-6 was spudded with the semi-submersible installation Borgny Dolphin 2 January 1986 and drilled to TD at 1800 m in the Early Jurassic Ror Formation. Drilling proceeded without significant problems. The well was drilled with seawater and bentonite down to807 m, with KCl/polymer mud from 807 m to 1603 m, and with chalk mud from 1603 m to TD.

The Rogn Formation was encountered oil-bearing from the top at 1642.5 m (1617.5 m SS) down to the base at 1660 m (1633.5 m SS). Average reservoir quality over this 17.5 m interval was very good, with calculated hydrocarbon saturation of 79 % and an average porosity of 31 %. Core permeabilities in the oil-bearing interval typically ranged between 1 and 10 Darcy. The underlying Fangst Group was interpreted as fully water bearing below 1671 m (1646 m SS), however low hydrocarbon saturations were calculated in the interval 1662 m to 1671 m (1637 - 1646 m SS). These were confirmed by the observed fluorescence in the cores over this interval and by Dean-Stark fluid saturation measurements.

Four cores were cut in the interval 1646 - 1690.2 m. An FMT survey gave the same reservoir oil and water gradients as in the other wells on Draugen, and it was found that the Rogn Formation and the Fangst Group belong to the same pressure regime. One FMT fluid sample was taken at 1652.5 m in the Rogn Formation. After the well was plugged an intermittent stream of gas bubbles was observed leaking from the wellhead. Analysis of a sample of the gas s
wlbHistoryDateUpdated: 2016-07-06T00:00:00