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The case of the missing clay, aluminium loss and secondary porosity, South Brae Oilfield, North Sea

Published online by Cambridge University Press:  09 July 2018

Ó. M. McLaughlin
Affiliation:
Department of Geology, University of Glasgow, Lilybank Gardens, Glasgow G12 8QQ, UK
R. S. Haszeldine
Affiliation:
Department of Geology, University of Glasgow, Lilybank Gardens, Glasgow G12 8QQ, UK
A. E. Fallick
Affiliation:
Scottish Universities Research and Reactor Centre, Isotope Unit, East Kilbride, G75 0QU, UK
G. Rogers
Affiliation:
Scottish Universities Research and Reactor Centre, Isotope Unit, East Kilbride, G75 0QU, UK

Abstract

Upper Jurassic sandstones of the South Brae Field were deposited as a submarine fan complex. The earliest formed concretionary ferroan calcite cement passively encloses detrital feldspars which originally formed more than 10% of the rock. Later non-ferroan calcite at the concretion margins was precipitated from a more aggressive fluid. This fluid dissolved up to half of the feldspars and micas originally present, but little or no clay was precipitated. Aluminium must have been lost from the system.

A late dissolution event has enhanced porosity by up to 8%. Feldspar was again reduced in volume by about half, leaving only ∼2% in the rock today. Very minor amounts of fibrous illite and kaolinite (<1%) form the last diagenetic cement. Aluminium must have again been lost from the system.

As the Kimmeridge Clay Formation (KCF) encloses and interdigitates with the South Brae sandstones, a local source of organic acids is quite possible. These acid solutions may have increased the mobility of Al. The Al from the feldspars must have therefore been transported vertically into the KCF, or more probably transported laterally by compactional flows out of the basin (up to 10 km) during release of overpressured basinal water.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1994

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References

Baldwin, B. & Butler, C.O. (1985) Compaction curves. Bull. Am. Assoc. Pet. Geol. 69, 622626.Google Scholar
Bjørlykke, K. (1980) Clastic diagenesis and basin evolution. Revista del lnstituo Geologas, Diputacion Provincial Universidud de Barcelona, 34, 21–44.Google Scholar
Bjørlykke, K. (1984) Formation of secondary porosity: how important is it? Pp. 277-286 in: Clastic Diagenesis (McDonald, D.A. & Surdam, R.C., editors). Mem. Am. Assoc. Pet. Geol. Spec. Publ. 37.Google Scholar
Bjørlykke, K., Elverhoi, A. & Malm, A.O. (1979) Diagenesis in Mesozoic sandstones from Spitsbergen and the North Sea-A comparison. Geol. Rund. 68, 11521172.Google Scholar
Bjørlykke, K., Ramm, M. & Saigal, G.C. (1989) Sandstone diagenesis and porosity modification during basin evolution. Geol. Rund, 78/1, 243268.Google Scholar
Bögli, A. (1964) Mischungskorrosion, ein Beitrag zum Verkastungsproblem. Erdkunde, 18, 8392.Google Scholar
Boles, J.R. & Johnson, K.S. (1983) Influence of mica surfaces on porewater pH. Chem. Geol. 43, 303317.Google Scholar
Buhrig, C. (1989) Geopressured Jurassic reservoirs in the Viking Graben: modelling and geological significance. Mar. Petrol. Geol. 6, 3148.Google Scholar
Burke, W.H., Denison, R.E., Hetherington, E.A., Koepnick, R.B., Nelson, H.F. & Otto, J.B. (1982) Variation of seawater 87Sr/86Sr throughout Phanerozoic time. Geology 10, 516519.Google Scholar
Carothers, W.W. & Kharaka, Y.K. (1978) Aliphatic acid ions in oil-field waters— implications for origin of natural gas. Butt. Am. Assoc. Petrol. Geol. 62, 24412453.Google Scholar
Friedman, I. & O'Neil, J.R. (1977) Compilation of stable isotope fractionation factors of geochemical interest. In: Data of Geochemistry, sixth edition, (Feischer, M., editor). U.S. Geol, Surv. Prof. Paper, 440-kk.Google Scholar
Giles, M.R. (1987) Mass transfer and problems of secondary porosity creation in deeply buried hydrocarbon reservoirs. Mar. Pet. Geol. 4, 188204.Google Scholar
Giles, M.R. & De Boer, R.B. (1989) Secondary porosity: creation of enhanced porosities in the subsurface from the dissolution of carbonate cements as a result of cooling formation waters. Mar. Petrol. Geol. 6, 261269.Google Scholar
Giles, M.R. & De Boer, R.B. (1990) Origin and significance of redistributional secondary porosity. Mar. Pet. Geol. 7, 378397.Google Scholar
Giles, M.R. & Marshall, J.D. (1986) Constraints on the development of secondary porosity in the subsurface: reevaluation of processes. Mar. Petrol. Geol. 3, 243255.Google Scholar
Hamilton, P.J., Fallick, A.E., Macinfyre, R.M. & Elliott, 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
Harris, N.B. (1989) Diagenetic quartzarenite and destruction of secondary porosity: an example from the Middle Jurassic Brent sandstones of N.W. Europe. Geology 17, 361364.Google Scholar
Hudson, J.D. & Andrews, J.E. (1987) The diagenesis of the Great Estuarine Group, Middle Jurassic, Inner Hebrides, Scotland. Pp. 259276 in: Diagenesis of Sedimentary Sequences (Marshall, J.D., editor). Blackwell, Oxford.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, 209213.Google Scholar
Lundegard, P.D., Land, L.S. & Galloway, W.E. (1984) Problem of secondary porosity: Frio Formation (Oligocene), Texas Gulf Coast. Geology 12, 399402.Google Scholar
Mackenzie, A.S., Price, I., Leythaeuser, D., Muller, P., Radke, M. & Schaefer, R.G. (1987) The expulsion of petroleum from Kimmeridge Clay source rocks in the area of the Brae Oilfield, UK. Pp. 865-877 in: Petroleum Geology of North West Europe (Brooks, J. & Glennie, K., editors). Graham & Trotman, London.Google Scholar
Magara, K. (1976) Water expulsion from clastic sediments during compaction, directions and volumes. Bull. Am. Assoc. Petrol. Geol. 60, 543553.Google Scholar
Mcbride, E.F. (1963) A classification of common sandstones. J. Sed. Pet. 33, 664669.Google Scholar
Mclaughlin, Ó.M. (1992) Isotopic and textural evidence for diagenetic fluid mixing in the South Brae Oilfield, North Sea. PhD thesis, Glasgow Univ., UK.Google Scholar
Nedkvlrne, T. & Bjørlykke, K. (1992). Secondary porosity in the Brent Group (middle Jurassic), Hulda Field, North Sea: implication for predicting lateral continuity of sandstones. J. Sed. Pet. 62, 2334.Google Scholar
Roberts, M.J. (1991) The South Brae Field, Block 16/7a, UK North Sea, Pp. 55-62 in: United Kingdom Oil and Gas fields, 25 years commemorative volume (Abbotts, I.L., editor). Geol. Soc. Mem. 14.Google Scholar
Shackleron, N.J. & Kennerr, J.P. (1975) Paleotemperature history of the Cenezoic and the initiation of Antarctic glaciation: oxygen and carbon analyses in DSDP sites 277, 279, 281. Pp. 653-659 in: lnitial Report DSDP 24, (Kennett, J.P. & Howtz, R.E., editors). Washington.Google Scholar
Stoker, M.J. & Brown, S. (1986) Coulee clastic sediments of the Brae field and adjacent areas, North Sea: a core workshop, British Geological Survey, Edinburgh.Google Scholar
Surdam, R.C., Boese, S.W. & Crossly, L.J. (1984) The chemistry of secondary porosity. Pp, 127-150 in: Clastic Diagenesis (McDonald, D.A. & Surdam, R.C., editors). Am. Assoc. Petrol. Geol. 37.Google Scholar
Turner, C.C. & Connell, E.R. (1991) Stratigraphic relationships between Upper Jurassic submarine fan sequences in the Brae Area, U.K. North Sea: the implications for reservoir distribution. Offshore Technology Conference 6508, Houston, 83-91.Google Scholar
Ziegler, P.A. (1978) North-Western Europe: tectonics and basin development. Geol. Mijn. 57, 589626.Google Scholar