Reservoir quality analysis of a mature play: The Brent Group, North Sea
- Exxon Production Research Co., Houston, TX (United States)
- Esso Exploration and Production Company, UK Ltd., Leatherhead (United Kingdom)
A basin-scale, integrated study of reservoir quality controls was undertaken to assess the remaining deep potential of the Brent Group. The study included a regional sequence stratigraphic and facies model incorporating 398 wells, over 32,000 feet of core and 1255 thin sections from the UK and Norwegian sectors of the North Viking Graben. It has been well established that the Brent Group shows an abrupt reduction in permeability at depth related to fibrous illite growth. However, the depth threshold and extent of permeability reduction are not uniform across the basin: in general, the eastern margin of the graben and Tampen Spur are less susceptible to illitization than the East Shetland Basin to the west. These differences arise from the cumulative effects of : (1) regional variations in composition related to facies distribution, with feldspar, mica- and kaolinite-rich shoreface sandstones increasing in relative abundance to the north and west, (2) facies-independent variations in sandstone composition, with sandstones on average 10% more quartzose east of the Viking Graben axis, (3) regional trends in formation pressure. Elevated formation pressures in and adjacent to the Viking Graben have a dramatic, facies-independent effect on reservoir quality, with porosity enhancement of as much as 10% rock volume over normally pressured sandstones to the west. The effects of each of these controls on Brent depth-reservoir quality trends can be quantified due to the size and stability of the database, and their distribution can be mapped from well control. Combining these maps with depth and isopach data from seismic control yields a basin-scale reservoir risking framework for the Brent Group.
- OSTI ID:
- 6576377
- Report Number(s):
- CONF-960527-; CODEN: AABUD2
- Journal Information:
- AAPG Bulletin, Vol. 5; Conference: Annual convention of the American Association of Petroleum Geologists, Inc. and the Society for Sedimentary Geology: global exploration and geotechnology, San Diego, CA (United States), 19-22 May 1996; ISSN 0149-1423
- Country of Publication:
- United States
- Language:
- English
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