Clay mineral distribution in the Devonian-Carboniferous sandstones of the Clair Field, west of Shetland, and its significance to reservoir quality

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doi: 10.1180/000985500546549
Authors:Pay, M. D.; Astin, T. R.; Parker, A.
Author Affiliations:Primary:
University of Reading, Postgraduate Research institute for Sedimentology, Reading, United Kingdom
Volume Title:Mineral diagenesis and reservoir quality, the way forward
Volume Authors:Bain, D. C., editor; Hall, P. L.; Shaw, H. F.; Spears, D. A.
Source:Clay Minerals, 35(1), p.151-162; Sixth Cambridge conference on Mineral diagenesis and reservoir quality, the way forward, Cambridge, United Kingdom, March 26-27, 1998, edited by D. C. Bain, P. L. Hall, H. F. Shaw and D. A. Spears. Publisher: Mineralogical Society, London, United Kingdom. ISSN: 0009-8558
Publication Date:2000
Note:In English. 18 refs.; illus., incl. sects., 1 table, sketch map
Summary:The Devonian-Carboniferous reservoir of the Clair Field contains a complex and variably abundant clay mineral assemblage. An abrupt vertical change in clay mineralogy has been observed in both wells studied (UKCS 206/8-7 and 206/8-8) from being rich in Mg-chlorite, chlorite-smectite (including dioctahedral corrensite), illite, illite-smectite and Fe-chlorite, to being smectite-rich. This change broadly coincides with the unconformable boundary between the Lower Clair Group and Upper Clair Group of the reservoir which possibly defines the Devonian-Carboniferous boundary. The clay minerals present reflect interaction between: (1) tectonic stability and climate that controlled the detrital composition of the sediment; (2) the pore-waters that developed; and (3) the result of diagenetic modification. Matrix porosity and permeability is severely restricted where the pore-lining clays are abundant (>15%) and where the clays bridge or fill pores. The type of clay mineral species appears to have a minor influence on reservoir quality, although they may be extremely important during production. The best reservoir quality occurs in mature aeolian sediments with a thin illite and illite-smectite clay coating.
Sections:Clay minerals
Subsections:Petrology; weathering; soils
Subjects:Authigenic minerals; Carboniferous; Chlorite; Chlorite group; Clastic rocks; Clay mineralogy; Clay minerals; Devonian; Diagenesis; Distribution; Illite; Paleozoic; Petroleum; Petroleum engineering; Petroleum exploration; Reservoir properties; Reservoir rocks; Sandstone; Sedimentary rocks; Sheet silicates; Silicates; Smectite; Atlantic Ocean; East Shetland Basin; North Atlantic; North Sea; Clair Field
Coordinates:N610000 N610000 W0030000 W0030000
Abstract Numbers:01M/121
Record ID:2000057290
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute.
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