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Implications of Linearly Correlated Oxygen and Hydrogen Isotopic Compositions for Kaolinite and Illite in the Magnus Sandstone, North Sea

Published online by Cambridge University Press:  28 February 2024

A. E. Fallick ,
C. I. Macaulay  and
R. S. Haszeldine
A. E. Fallick
Affiliation:
Isotope Geology Unit, Scottish Universities Research and Reactor Centre, East Kilbride, Glasgow, G75 0QU, Scotland
C. I. Macaulay
Affiliation:
Isotope Geology Unit, Scottish Universities Research and Reactor Centre, East Kilbride, Glasgow, G75 0QU, Scotland Department of Geology and Applied Geology, Glasgow University, Lilybank Gardens, Glasgow, G12 8QQ, Scotland
R. S. Haszeldine
Affiliation:
Department of Geology and Applied Geology, Glasgow University, Lilybank Gardens, Glasgow, G12 8QQ, Scotland
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Abstract

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Authigenic kaolinite and illite are important diagenetic minerals in the Magnus Sandstone, a giant oil reservoir in the northern North Sea. These clay minerals, separated from three wells, show considerable ranges in their oxygen isotopic composition (δ8OSMOW = +9 to + 16%) and hydrogen isotopic composition (δDSMOW = - 55 to - 105%). The variations in δ18O and δD are positively linearly correlated with a high degree of statistical significance for both kaolinite and illite:

Kaolinite:n=12;δD=6.1δ18O−169;r=0.66(>95%)Illite:n=11;δD=5.9δ18O−159;r=0.78(>99%).

Formation of the clays in a pore fluid of uniform isotopic composition over a range of temperatures appears unlikely. It is suggested that the observed relationships between clay mineral δ18O and δD are perhaps best explained by a model of precipitation at more or less constant temperature from pore fluids which varied isotopically across the oilfield. The isotopic composition of the formation waters would then lie along the line: δDw = 6.2 δl8Ow - 50. This is most plausibly interpreted as a mixing line with suggested minimal endmembers at (δ18O, δD) values of (+4, -24) and (-4, -76). The first of these represents reasonable isotopic values for Magnus Sandstone formation waters. Although δ18O of the second is compatible with an evolved Cretaceous meteoric water, its δD value is difficult to understand in the context of the model.

Keywords

IlliteKaoliniteStable isotopesPorewater
Type
Research Article
Information
Clays and Clay Minerals , Volume 41 , Issue 2 , April 1993 , pp. 184 - 190
Copyright
Copyright © 1993, The Clay Minerals Society

References

Aplin, A. C., Warren, E. A. and Grant, S. M., 1992 Mechanism of quartz cementation in North Sea reservoir sands: Constraints from fluid compositions Bull. A.A.P.G. .Google Scholar
Borthwick, J. and Harmon, R. S., 1982 A note regarding ClF3 as an alternative to BrF5 for oxygen isotope analysis Geochim. Cosmochim. Acta 46 1665 – 1668 10.1016/0016-7037(82)90321-0.CrossRefGoogle Scholar
Carstens, H., Finstad, K. G., Illing, L. V. and Hobson, G. D., 1981 Geothermal gradients of the northern North Sea Basin, 59-62°N Petroleum Geology of the Continental Shelf of North West Europe 152 – 161.Google Scholar
Clayton, R. N. and Mayeda, T. K., 1963 The use of bromine pentafluoride in the extraction of oxygen from oxides and silicates for isotopic analysis Geochim. Cosmochim. Acta 27 43 – 52 10.1016/0016-7037(63)90071-1.CrossRefGoogle Scholar
Coleman, M. L., 1992 Intra-field variations in formation waters The Chemistry and Origins of North Sea Formation Waters: Implications for Diagenesis and Production Chemistry .Google Scholar
Craig, H., 1961 Isotopic variations in meteoric waters Science 133 1702 – 1703 10.1126/science.133.3465.1702.CrossRefGoogle ScholarPubMed
De’Ath, N. G., Schuyleman, S. F., Illing, L. V. and Hobson, G. D., 1981 The geology of the Magnus Oilfield Petroleum Geology of the Continental Shelf of North West Europe London Heyden and Son 342 – 351.Google Scholar
Eberl, D. D., Srodon, J., Kralik, M., Taylor, B. E. and Peterman, Z. E., 1990 Ostwald ripening of clays and meta-morphic minerals Science 248 474 – 477 10.1126/science.248.4954.474.CrossRefGoogle Scholar
Egeberg, P. K. and Aagaard, P., 1989 Origin and evolution of formation waters from oilfields on the Norwegian shelf App. Geochem. 4 131 – 142 10.1016/0883-2927(89)90044-9.CrossRefGoogle Scholar
Emery, D., Myers, K. J. and Young, R., 1990 Ancient subaerial exposure and freshwater leaching in sandstones Geology 18 1178 – 1181 10.1130/0091-7613(1990)018<1178:ASEAFL>2.3.CO;2.2.3.CO;2>CrossRefGoogle Scholar
Emery, D., Robinson, A. G., Smalley, P. C., Fallick, A. E. and Clayton, T., 1990 Morphological and isotopic evidence for multiple kaolinite generation in Brent group sandstones (Abs) Geol. Soc. Lond. Newsletter 19 31.Google Scholar
Fallick, A. E., Jocelyn, J., Guy, M., Donnelly, T. and Behan, C., 1985 Origin of agates in volcanic rocks from Scotland Nature 313 672 – 674 10.1038/313672a0.CrossRefGoogle Scholar
Forester, R. W. and Taylor, H. P., 1977 18O/16O, D/H, and 13C/12C studies of the Tertiary igneous complex of Skye, Scotland Am. J. Sci. 277 136 – 177 10.2475/ajs.277.2.136.CrossRefGoogle Scholar
Glasmann, J. R., Lundegard, P. D., Clark, R. A., Penny, B. K. and Collins, I. D., 1989 Geochemical evidence for the history of diagenesis and fluid migration: Brent sandstone, Heather Field, North Sea Clay Miner. 24 255 – 284 10.1180/claymin.1989.024.2.10.CrossRefGoogle Scholar
Hamilton, P. J., Fallick, A. E., Macintyre, R. M., Elliot, S., Brooks, J. and Glennie, K., 1987 Isotopic tracing of the provenance and diagenesis of Lower Brent Group sandstones, North Sea Petroleum Geology of North West Europe London Graham and Trotman 939 – 949.Google Scholar
Hamilton, P. J., Giles, M. R., Ainsworth, P., Morton, A. C., Haszeldine, R. S., Giles, M. R. and Brown, S., 1992 K-Ar dating of illites in Brent Group reservoirs: A regional perspective Geology of the Brent Group London The Geological Society 377 – 400.Google Scholar
Jackson, M. L., 1956 Soil Chemical Analysis—Advanced Course Madison Department of Soil Science, University of Wisconsin.Google Scholar
Jackson, M. L., 1979 Soil Chemical Analyses—Advanced Course 2nd Edition Madison Department of Soil Science, University of Wisconsin.Google Scholar
Kantorowicz, J. D., 1990 The influence of variations in illite morphology on the permeability of middle Jurassic Brent group sandstones, Cormorant Field, UK North Sea Marine and Petrol. Geol. 7 66 – 74 10.1016/0264-8172(90)90057-N.CrossRefGoogle Scholar
Knauth, L. P. and Epstein, S., 1976 Hydrogen and oxygen isotope ratios in nodular and bedded cherts Geochim. Cosmochim. Acta 40 1095 – 1108 10.1016/0016-7037(76)90051-X.CrossRefGoogle Scholar
Lee, M., Aronson, J. L. and Savin, S. M., 1985 K/Ar dating of time of gas emplacement in Rotliegendes Sandstone, Netherlands Bull. AAPG 69 1381 – 1385.Google Scholar
Lee, M., Aronson, J. L. and Savin, S. M., 1989 Timing and conditions of Permian Rotliegende sandstone diagenesis, southern North Sea: K/Ar and oxygen isotopic data Bull. AAPG 73 195 – 215.Google Scholar
Longstaffe, F. J. and Ayalon, A., 1990 Hydrogen-isotope geochemistry of diagenetic clay minerals from Cretaceous sandstones, Alberta, Canada: Evidence for exchange App. Geochem. 5 657 – 668 10.1016/0883-2927(90)90063-B.CrossRefGoogle Scholar
Macaulay, C. I., Haszeldine, R. S. and Fallick, A. E., 1992 Diagenetic pore waters stratified for at least 35 million years: Magnus Oilfield, North Sea Bull. AAPG 76 1625 – 1634.Google Scholar
Macaulay, C. I., Haszeldine, R. S. and Fallick, A. E., 1992 Textural and isotopic variations in diagenetic kaolinite from the Magnus Oilfield sandstones Clay Miner. .CrossRefGoogle Scholar
Macaulay, C. I., Haszeldine, R. S. and Fallick, A. E., 1993 Distribution, chemistry, isotopic composition and origin of diagenetic carbonates: Magnus sandstone, North Sea J. Sed. Pet. 63 33 – 43.Google Scholar
McHardy, W. J., Wilson, M. J. and Tait, J. M., 1982 Electron microscope and X-ray diffraction studies of filamentous illitic clay from sandstones of the Magnus field Clay Miner. 17 23 – 29 10.1180/claymin.1982.017.1.04.CrossRefGoogle Scholar
Mehra, O. P. and Jackson, M. L., 1960 Iron oxide removal from soils and clays by a dithionite-citrate system buffered by sodium bicarbonate Clays and Clay Miner 317 – 327.CrossRefGoogle Scholar
O’Neil, J. R. and Kharaka, Y. K., 1976 Hydrogen and oxygen isotope exchange reactions between clay minerals and water Geochim. Cosmochim. Acta 40 241 – 246 10.1016/0016-7037(76)90181-2.CrossRefGoogle Scholar
O’Neil, J. R., 1986 Theoretical and experimental aspects of isotopic fractionation Rev. Mineral. 16 1 – 40.Google Scholar
Savin, S. M. and Lee, M., 1988 Isotopic studies of phyl-losilicates Rev. Mineral. 19 189 – 224.Google Scholar
Shepherd, M. and Abbotts, I. L., 1991 The Magnus field, blocks 21 l/7a, 12a, U.K. North Sea United Kingdom Oil and Gas Fields 25 Years Commemorative Volume London The Geological Society 153 – 157.Google Scholar
Sheppard, S. M. F., 1986 Characterization and isotopic variations in natural waters Rev. Mineral. 16 165 – 183.Google Scholar
Wilson, M. R., Kyser, T. K., Mehnert, H. H. and Hoeve, J., 1987 Changes in the H-O-Ar isotope composition of clays during retrograde alteration Geochim. Cosmochim. Acta 51 869 – 878 10.1016/0016-7037(87)90100-1.CrossRefGoogle Scholar