Hostname: page-component-848d4c4894-2xdlg Total loading time: 0 Render date: 2024-06-29T13:50:39.014Z Has data issue: false hasContentIssue false
  • English
  • Français

Fracturing, overpressure release and carbonate cementation in the Everest Complex, North Sea

Published online by Cambridge University Press:  09 July 2018

D. M. Conybeare  and
H. F. Shaw
D. M. Conybeare*
Affiliation:
Baker Atlas Geoscience, Kettock Lodge, Campus 2, Science and Technology Park, Balgownie Drive, Aberdeen AB22 8GU
H. F. Shaw
Affiliation:
T.H. Huxley School of Environment, Earth Sciences and Engineering, Imperial College, London SW7 2BP, UK
*
*E-mail: david.conybeare@bakeratlas.com
Get access Rights & Permissions [Opens in a new window]

Abstract

The Palaeocene Everest Complex, located in the Central Graben of the North Sea, comprises interbedded sandstones and mudrocks deposited in a submarine fan environment and overlies Cretaceous limestones. Depositional facies are the main influence on reservoir quality, although the latter is reduced significantly locally by ferroan calcite cementation, particularly in the lower part of the complex. Carbon and O stable isotope analyses have been made from cements in sandstones and mudrocks and from shear fractures and injection features within mudrock intervals. These indicate a marine source of detrital carbonate becoming mixed with HCO3− from decarboxylation higher in the succession. Petrographic observation and microprobe analyses indicate that dissolution of coccoliths and foraminifera in limestones are the principal sources of cementation. The similar composition of cements in sandstones, fractures and injection features suggests a common formation. Burial history modelling shows cement precipitation is synchronous with periods of excess pressure and therefore excess pressure release associated with rock failure is proposed as a prominent mechanism for initiating cementation.

Keywords

overpressureEverest ComplexNorth Seacarbonate cement
Type
Research Article
Information
Clay Minerals , Volume 35 , Issue 1 , March 2000 , pp. 135 - 149
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2000

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Cartwright, J.A. (1994) Episodic basin-wide fluid expulsion from geopressured shale sequence in the North Sea basin. Geology, 22, 22–447.2.3.CO;2>CrossRefGoogle Scholar
Cartwright, J.A. (1996) Polygonal fault systems in the North Sea Tertiary revealed by 3D seismic data. Pp. 225-30 in: Applications of 3-D Seismic Data to Exploration and Production (Weimer, P., editor). American Association of Petroleum Geologists, Studies in Geology, 42.Google Scholar
Conybeare, D.M. (1996) Diagenesis and reservoir quality in the Everest Complex, North Sea. PhD thesis, London Univ., UK.Google Scholar
Coleman, M.L. & Raiswell, R. (1981) Carbon, oxygen and sulphur isotope variations in carbonate concretions from the Upper Lias of NE England. Geochim. Cosmochim. Acta, 45, 45–329.CrossRefGoogle Scholar
Curtis, C.D. (1977) Sedimentary geochemisty: Environments and processes dominated by involvement of an aqueous phase. Phil. Trans. Royal Soc, Land. 137, 137–189.Google Scholar
Curtis, C.D. (1978) Possible links between sandstone diagenesis and depth related geochemical reactions occurring in enclosing mudrocks. J. Geol. Soc. 135, 135–107.Google Scholar
Curtis, C.D. & Coleman, MX. (1986) Controls on the precipitation of early diagenetic calcite, dolomite and siderite concretions in complex deposition. Pp. 375-386 in: Roles of Organic Matter in Sediment Diagenesis (Gautier, D.X., editor). Society of Economic Mineralogy and Palaeontology, Spec. Publ. 38.Google Scholar
Ehrenberg, S.N. (1995) Measuring sandstone compaction from modal analyses of thin sections: How to do it and what the results mean. J. Sed. Pet. 65, 65–369.CrossRefGoogle Scholar
Fallick, A.E., Macaulay CI. & Haszeldine, R.S. (1993) Implications of linearly correlated oxygen and hydrogen isotopic compositions for kaolinite and illite in the Magnus Sandstone, North Sea. Clays Clay Miner. 41, 41–184.CrossRefGoogle Scholar
Franks, P.C. (1969) Nature, origin and significance of cone-in-cone structures in the Kiowa Formation (Early Cretaceous), north-central Kansas. J. Sed. Pet. 39, 39–1438.Google Scholar
Friedman, I. & O'Neil, J.R. (1977) Compilation of stable isotope fractionation factors of geochemical interest. P. 12 in: Data of Geochemistry, Sixth Edition (Fleischer, M., editor). United States Geol. Surv. Prof. Paper, 440-KK.Google Scholar
Hall, P.X. (1994) Physical and chemical aspects of the development of overpressuring in sedimentary environments. Clay Miner. 29, 29–425.CrossRefGoogle Scholar
Hamilton, P.J., Fallick, A.E., Maclntyre, R.M. & Elliot, S. (1987) Isotopic tracing of the provenance and diagenesis of Lower Brent Group sands, North Sea. Pp. 939-949 in: Petroleum Geology of North West Europe (Brooks, J. & Glennie, K., editors). Graham & Trotman, London.Google Scholar
Haszeldine, R.S., Brint, H.F., Fallick, A.E., Hamilton, P.J. & Brown, S. (1992) Open and restricted hydrologies in Brent Group diagenesis, North Sea. Pp. 401-419 in: Geology of the Brent Group (Haszeldine, R.S., Giles, H.R. & Brown, S., editors). Geological Society London, Spec. Publ. 61.Google Scholar
Hubbert, M.K. & Rubey, W.W. (1959) Role of fluid pressure in mechanics of overthrust faulting. Geol. Soc. Am. Bull. 70. 115-166.Google Scholar
Irwin, H., Curtis, C. & Coleman, M. (1977) Isotopic evidence for source of diagenetic carbonates formed during burial of organic-rich sediments. Nature, 269, 269–209.Google Scholar
Kerlins, V. & Phillips, A. (1987) Modes of fracture. Metals Handbook, 12, 12–213.Google Scholar
Knox, R.W.O'B. & Holloway, S. (1992) Palaeogene of the Central and Northern North Sea. UKOOA.Google Scholar
Longstaffe, F.J. (1986) Oxygen isotope studies of diagenesis in the basal Belly River Sandstone. J. Sed. Pet. 56, 56–78.Google Scholar
Macaulay, C.I, Haszeldine, R.S. & Fallick, A.E. (1993) Textural and isotopic variations in diagenetic kaolinite from the Magnus oilfield sandstones. Clay Miner. 28, 28–625.Google Scholar
Marshal, J.D. (1982) Isotopic composition of displacive fibrous calcite veins: Reversals in pore water composition trends during burial diagenesis. J. Sed. Pet. 52, 52–615.Google Scholar
Mozley, P.S. & Wersin, P. (1992) Isotopic composition of siderite as an indicator of depositional environment. Geology, 20, 20–817.Google Scholar
O'Connor, S.J. & Walker, D. (1993) Palaeocene reservoirs of the Everest trend. Pp. 145-160 in: Petroleum Geology of North West Europe: Proc. 4th Conf. (Parker, J.R., editor). Geological Society, London.Google Scholar
Osborne, M., Haszeldine, S. & Fallick, A.E. (1994) Isotopic constraints upon clay precipitation and pore water evolution, Brent Group, UK. P. 34 in: Diagenesis, Overpressure and Reservoir Quality. Mineralogical Society, Cambridge Clay Meeting, Abstracts.Google Scholar
Scotchman, I.C. (1987) Clay diagenesis in the Kimmeridge Clay Formation, onshore UK, and its relation to organic maturation. Mineral. Mag. 51. 535-551.Google Scholar
Sclater, J.G. & Christie, P.A.F. (1980) Continental stretching: An explanation of the Post-Mid- Cretaceous subsidence of the Central North Sea Basin. J. Geophys. Res. 85. 3711-3739.Google Scholar
Selley, R.C. (1978) Porosity gradients in North Sea oilbearing sandstones. J. Geol. Soc. London, 135, 135–119.Google Scholar
Stewart, R.N.T., Fallick, A.E. & Haszeldine, R.S. (1994) Kaolinite growth during pore-water mixing, isotopic data from Palaeocene sands, North Sea, UK. Clay Miner. 29, 29–627.Google Scholar
Surdam, R.C., Crossey, L.J., Hagen, E.S. & Heasler, H.P. (1984) Organic-inorganic interactions and sandstone diagenesis. Am. Assoc. Petrol. Geol. Bull. 73, 73–1.Google Scholar
Tissot, B.P., Durand, B., Espitalie I & Combax, A. (1974) Influence of nature and diagenesis of organic matter in formation of petroleum. Am. Assoc. Petrol. Geol. Bull. 58, 58–499.Google Scholar
Thompson, P.J. & Butche r, P.D. (1991) The geology and geophysics of the Everest Complex. Pp. 89-98 in: Generation, Accumulation and Production of Europe's Hydrocarbons (Spencer, A.M., editor). European Association of Petroleum Geoscientists. Oxford. Spec. Publ.Google Scholar
Zheng, Y.-F. (1990) Carbon-oxygen isotopic covariation in hydrothermal calcite during degassing of C02. Mineral. Deposita, 25, 25–246.Google Scholar