Raude Formation (elevated)

(From NPD Bulletin no. 1)

Statfjord Group


The formation is named after Eirik Raude (Raude = Red), the Viking discoverer of Greenland.

Well type section

Norwegian well 33/12-2 (Mobil) (Figure 17), from 2790 m (9153 ft) to 2951 m (9681 ft) below KB.

Well reference section

UK well 211/24-1 (Conoco/Gulf/NCB), Figure 17.


In the type well the member is 161 m (528 ft) thick and in 211/24-1 it is 119 m (391 ft).


In the type well the basal part of the formation consists of a 'coarsening upward' sequence of grey, green and red-brown silty claystones, grey arkosic sandstones and white, pink and grey-brown dolomitic limestones. This basal part of the section is often difficult to recognise away from the type well and is locally absent. Above 2905 m (9530 ft) in the type well the member consists of approximately equal amounts of sandstone and silty shale. These sandstones are fine to medium grained and poor to moderatley sorted with subangular grains. They are generally micaceous and have a kaolinite matrix. The silty shales are grey to light green or occasionally red-brown in colour, and micromicaceous. Carbonaceous debris, sometimes in thin laminae, is present but distinct lignite beds are absent. Away from the type well the sandstone percentage in this upper part of the formation may vary from about 15 to about 75. In the area of the Brent and Statfjord Fields the average sandstone bed thickness is about 2.5 m (8 ft) and shale beds average about 4 m (13 ft) in thickness. Correlation of individual beds from well to well is virtually impossible. The lithological content and sedimentary structures in the upper part of the formation, particularly large scale cross-bedding and scour and fill, are consistent with deposition in a braided stream environment.


The base of the member is the base of the Statfjord Group. The change from the more argillaceous Cormorant Formation sediments to the more sandy Statfjord Group via the transitional 'coarsening upward' unit is clearly defined on the gamma ray and sonic logs. The top of the formation is the base of the first massive sandstone of the overlying more arenaceous formation. This boundary is normally clearly marked by a change from an irregular to a more blocky log response, particularly in the gamma ray log. Individual sandstone beds in the overlying Eiriksson Formation are more laterally extensive and the base of the lowest sandstone which is correlatable between wells will egnerally indicate the top of the Raude Formation.


The formation can generally be recognised wherever the Statfjord Group is well developed. Teh basal 'coarsening upward' unit is though to have a more limited distribution but this cannot be defined as many wells terminated in or just above this basal unit.


Rhaetian. The top of the formation may approximate to the Rhaetian-Lower Jurassic boundary in the type well but is probably older to the west (Figure 18).

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