30/4-1

General

Well 30/4-1 is located north of the Hild Discovery and west of the Oseberg Field. The main target was Middle Jurassic sandstones in a complex fault and dip-controlled closure. Secondary targets were Palaeogene sands (Balder and Sele Formations) and possible Late Jurassic sands, both in simple dip closures.

Operations and results

Wildcat well 30/4-1 was spudded with the semi-submersible installation SEDCO 707 on 1 November 1978 and drilled to TD at 5454 m in the Early Jurassic Dunlin Group.

The well penetrated a mainly argillaceous Palaeogene section. However, a distinct interval of interbedded thin argillaceous water-bearing sandstones (beds 1 - 3 m thick) with thicker mudstone intervals was drilled between 2116.5 and 2162.5. The net/gross ratio of this interval was about 0.2 (20%) and the sandstone porosities average around 30% (from Schlumberger logs). The well then penetrated a thick argillaceous Cretaceous and Late Jurassic interval. No Late Jurassic sandstones were developed. Water bearing, Middle Jurassic sandstones of the Brent Group were encountered at 5181.5 m. This target group was 218.2 m thick, had a net/gross ratio of about 0.66 (66%) and had sandstone porosities ranging from around 4-16% (from Schlumberger logs). Shows were recorded in limestones in the interval 2545 m to 2570 m, with weaker shows extending down to 2630 m. Weak shows were also noted in the interval 2900 m to 3000 m. Geochemical analyses of cuttings confirmed migrant "medium gravity oil" in the interval 2570 m to 2630 m. No conventional cores were cut. Wire line RFT samples were attempted but all failed.

The well was permanently abandoned as dry on 14 May 1979.

Testing

No drill stem test was performed