ID: 824
OBJECTID: 824
wlbNpdidWellbore: 1989
wlbName: 30/9-B-18
wlbHistory:

General

Well 30/9-B-18 was drilled as a development well on the 30/9-1 Oseberg Discovery in the North Sea. It was drilled as a penetration well prior to the horizontal well 30/9-B-18 A. The objective was to accurately locate the oil/water contact in the Oseberg Formation and to give structural information and exact target depth for the horizontal section of the production well 30/9-B-18 A.

The NSO-1 geochemical standard oil was produced from 30/9-B-18 A.

Operations and results

Development well 30/9-B-18 was spudded on 10 June 1992. It was drilled from the Oseberg B platform to TD at 3980 m (2814 m TVD) m in the Early Jurassic Drake Formation. The target of the well was on the Oseberg Alpha Structure approximately 2.5 km south-east of the Oseberg B platform. Serious hole cleaning problems were evident throughout the 12 1/4" section, causing a sidetrack from 1448 m. The well was drilled with spud mud down to 1155 m, with ANCO 2000 mud from 1155 to 3342 m, and with oil based Safemul mud from 3342 m to TD.

The well drilled through a 121 metres vertical section of the Brent Group, which is 10 metres more than prognosed, and the oil-water contact was established at 3878 m MD (2767 m TVD). Good shows were observed on the cores from the Oseberg Formation, otherwise no shows descriptions were reported from the well. RFT pressure points proved an 11 bar depleted oil gradient compared to the initial Oseberg-Rannoch-Etive gradient in the Alpha structure.

Two cores were cut in succession from 3859 to 3903 m in the Oseberg Formation. The core-log depth shift is +2 m for both cores. The RFT was run on wireline to record pressure points in the
wlbHistoryDateUpdated: 2023-09-13T00:00:00