Wellesley spuds 6204/11-3: A distal well targeting a proximal sand

Wellesley spuds 6204/11-3: A distal well targeting a proximal sand

This week, Wellesley Petroleum, in partnership with Petoro (20%) and Equinor (20%), spudded well 6204/11-3 to test the Schweinsteiger prospect in PL829.

This week, Wellesley Petroleum, in partnership with Petoro (20%) and Equinor (20%), spudded well 6204/11-3 to test the Schweinsteiger prospect in PL829.

Although the well name suggests a Norwegian Sea setting, in map view it rather looks as if the well is pushing the northern limits of the Northern North Sea. The targeted formation is also a familiar to North Sea stratigraphy.

The well is located on the Måløy Slope, which is the platform bounding the Slørebotn Basin in the west. The Måløy Slope transitions into the More-Trondelag fault complex in a northerly direction.

The target reservoir of the well are sandstones belonging to the Lower Cretaceous Åsgard Formation, with expected medium to good reservoir properties. These sands were shed from the emerged Norwegian mainland to the east. The well is very close to the margin of the Norwegian landmass, which is probably the reason for the target to be very shallow (1071-1155 m TVDSS).

Seismic section through the Schweinsteiger prospect, showing the mapped flat spot. Source.

The expected fluids are oil with a gas cap, trapped in a 3-way closure in a rotated fault block. A direct hydrocarbon indicator (DHI, flatspot) observation has been made on seismic and is a strong indication of a gas/liquid contact.

The closure is thought to consist of a total of 164 metres of sandstone whereby the upper 84 metres (1071-1155m TVDSS) are expected to be gas-filled. Under the gas it is 80 meters down to the structural leak point 1235 m TVDSS. The well will be drilled to a depth of 1391 m.

It is interesting to note the well that was drilled closest to the current Schweinsteiger prospect is well 6204/10-1. Located about 5 km to the west, it drilled the Albian Agat Formation before hitting basement rocks at a depth of 2670 m. This means that a more complete Cretaceous section should be present at well 6204/11-3, given that the Åsgard Formation is mainly of a pre-Albian age. Well 6204/10-1 was dry.

HENK KOMBRINK

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