Regional distribution of diagenetic carbonate cement in Palaeocene deepwater sandstones; North Sea

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doi: 10.1180/000985500546521
Authors:Stewart, R. N. T.; Haszeldine, R. S.; Fallick, A. E.; Wilkinson, M.; Macaulay, C. I.
Author Affiliations:Primary:
University of Edinburgh, Department of Geology and Geophysics, Edinburgh, United Kingdom
Scottish Universities Research and Reactor Centre, 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.119-133; 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. 33 refs.; illus., incl. sects., 2 tables, sketch map
Summary:Sandstones of the Palaeocene Montrose Group were deposited in a deepwater fan environment, and form a major oil reservoir in the North Sea. Calcite concretions occur commonly within thick-bedded and structureless sandstones. These concretions have been identified by sonic logs and well reports, and were cross-checked with available core data. Regionally, 101 wells have been examined and carbonate concretions form 0.6-7.2% of the core. Concretions are most abundant along the flank of the Fladen Ground Spur, the north Witch Ground Graben (WGG), the east south Viking Graben and East Central Graben (ECG). Concretions of the ECG formed at deep burial, with C from decarboxylation. Geochemical inheritance of Mn and Sr from Cretaceous chalk clasts may occur. Concretion growth may also have been influenced by vertical expulsion of fluids (leak-off) localized above salt tectonics. Isotopic and petrographic evidence indicates that much carbonate C in the WGG was derived from biodegradation of migrating oil in meteoric water at shallow depth. The locations of abundant carbonate with characteristic negative C isotope signatures can be used as shallow exploration guides to leak-off points located above deep overpressured structures.
Sections:Clay minerals
Subsections:Petrology; weathering; soils
Subjects:Carbonates; Cement; Cenozoic; Deep-water environment; Degradation; Depositional environment; Diagenesis; Distribution; Paleocene; Paleogene; Petroleum; Petroleum exploration; Reservoir rocks; Tertiary; Atlantic Ocean; North Atlantic; North Sea; Montrose Group
Coordinates:N570000 N590000 E0020000 E0000000
Abstract Numbers:01M/119
Record ID:2000057288
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute.
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