Eldfisk Member

(From NPD Bulletin no. 3)

Tyne Group, Haugesund and Farsund Formations

Name

From the Eldfisk Field in Norwegian block 2/7.

Well type section

Norwegian well 2/7-3 (Phillips) from 3626 m to 3695 m, coord N56°23'02.9" E03°14'45.9" (Fig. 40, NPD Bulletin no. 3).

Well reference section

Norwegian well 1/9-3 (Statoil) from 4359.5 m to 4386.5 m, coord N56°24'56.2", E02°54'15.15" (Fig. 43, NPD Bulletin no. 3).

Thickness

69 m in the type well 2/7-3 and 27 m in the reference well.

Lithology

The Eldfisk Member consists predominantly of sandstone but contains substantial interbeds of shale. In the type well the sandstone is dark yellowish brown, fine to coarse grained, poorly sorted and generally angular, while the shale is medium light grey to dark grey. Both the sandstone and the shale contain calcareous streaks which produce high amplitude peaks on the sonic log.

Well 2/7-3.

Well 1/9-3.

Boundaries

The sands of the Eldfisk Formation are entirely enclosed within the thick upper Jurassic shale sequence of the Central Graben. The Eldfisk Member is therefore easily distinguished from the underlying Haugesund Formation and the overlying Farsund Formation by its lower gamma ray readings.

Distribution

As defined at present, the main development of the Eldfisk Formation is confined to the region of the Eldfisk Field, although thin time equivalent sands are present in other parts of the Central Graben.

Age

Kimmeridgian

Depositional environment

The Eldfisk Formation represents an influx of sand into the axial portions of the Central Graben at a time of regression, and for this reason it is postulated that the formation is turbiditic in origin. However, no conventional cores have been taken in the sands and there is no definitive sedimentological evidence.

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