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NORLEX


Flekkefjord Formation

(From NPD Bulletin no. 3)

Boknfjord Group

Name

From a town on the south-west coast of Norway. This formation was formerly included in the Valhall Formation of the Cromer Knoll Group (Deegan and Scull, 1977). The same unit was defined as the Flekkefjord Member by Rawson and Riley (1982), and is here elevated to formation status.

Well type section

Norwegian well 9/4-2 (Texaco) from 2155 m to 2208 m, coord N 5741'11.05" E 0402'34.85",(Fig. 38).

Well reference section

Norwegian well 8/1-1 (Phillips) from 2379 m to 2425 m, coord N 5751'43.53", E 0312'27.64",(Fig. 37).

Thickness

In the type well it is 53 m, and in the reference well it is 46 m. This is also the approximate thickness in most wells within the Egersund Sub-Basin.

Lithology

The formation consists of dark grey shales which are variably carbonaceous, pyritic and may contain thin limestone stringers.

Boundaries

The lower boundary of the formation is clearly defined both on gamma and sonic logs by the contact with the more silty Sauda Formation. The upper boundary usually appears as a distinct log break, with higher radioactivity and higher interval transit times in the Flekkefjord Formation. In the Egersund Sub-Basin, which is situated closer to the source area, the boundary may be difficult to identify on logs.

Distribution

The formation is present in the Norwegian-Danish Basin. It is time-equivalent to the upper part of the Mandal Formation in the graben areas to the west and to the Fredrikshavn Unit C in the Danish sector to the east (Michelsen, 1978)

Occurrences of formation tops in wells
Isochore map SAUDA-FLEKKEFJORD

Age

Ryazanian.

Depositional environment

The Flekkefjord Formation was deposited in a marine, low-energy, basinal environment.

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