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The ion content and mineralogy of a North Sea Cretaceous shale formation

Published online by Cambridge University Press:  09 July 2018

T. G. J. Jones ,
T. L. Hughes  and
P. Tomkins
T. G. J. Jones
Affiliation:
Schlumberger Cambridge Research, High Cross, Madingley Road, Cambridge CB3 0HG
T. L. Hughes
Affiliation:
Schlumberger Cambridge Research, High Cross, Madingley Road, Cambridge CB3 0HG
P. Tomkins
Affiliation:
Schlumberger Cambridge Research, High Cross, Madingley Road, Cambridge CB3 0HG
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Abstract

The shale from the Witch Ground Graben in the North Sea consists mostly of clay and calcite with relatively small amounts of quartz and plagioclase. The clay mineralogy is dominated by smectite and illite with varying amounts of chlorite and kaolinite. The ion composition was determined by ion chromatography, the porewater anions and cations being removed by leaching the shale with water, while the exchange cations were removed by reacting the shale with a large excess of tetramethylammonium ions. The clay mineralogy from XRD is consistent with the measured values of CEC. The water content and wireline log conductivity of the shale is controlled largely by the CEC (i.e. clay mineralogy). The cation content of the shale section is dominated by Na, with only small concentrations of K, Mg and Ca ions. The total anion concentration, which is dominated by chloride, shows an inverse relation to the concentration of exchange sites in the shale, suggesting that the compaction of the shale is to some extent controlled by a Donnan or salt-exclusion mechanism. Application of the Donnan equilibrium led to the reasonable conclusion that the shale is in compactional equilibrium with an external reservoir of about four times the anion content of seawater. The extent of salt exclusion in the shale is relatively low—a consequence of the high salt concentration in the external formation and the relatively low concentration of exchange sites in the shale.

Type
Research Article
Information
Clay Minerals , Volume 24 , Issue 2 , June 1989 , pp. 393 - 410
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1989

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References

Appelo, C.A.J. (1977) Chemistry of water expelled from compacting clay layers: a model based on Donnan equilibrium. Chem. GeoL, 19, 91–98.CrossRefGoogle Scholar
Benzel, W.M. & Graf, D.L. (1984) Studies of smectite membrane behavior: importance of layer thickness and fabric in experiments at 20°C. Geochim. Cosmochim. Acta, 48, 1769–1778.Google Scholar
Berry, F.A.F. (1969) Relative factors influencing membrane filtration effects in geologic environments. Chem. Geol., 4, 295–301.Google Scholar
Brightman, M.A., Bath, A.H., Cave, M.R. & Darling, W.G. (1985) Pore fluids from the argillaceous rocks of the Harwell region. British Geological Survey Report FLPU 85-6. Keyworth, UK.Google Scholar
Bruce, C.H. (1984) Smectite dehydration-its relation to structural development and hydrocarbon accumulation in Northern Gulf of Mexico basin. Am. Assoc. Pet. Geol. Bull., 68, 673–683.Google Scholar
Burst, J.F. (1969) Diagenesis of Gulf Coast clayey sediments and its possible relation to petroleum migration. Am. Assoc. Pet. Geol. Bull., 53, 73–93.Google Scholar
Carstens, H. & Dypvik, H. (1981) Abnormal formation pressure and shale porosity. Am. Assoc. Pet. Geol. Bull., 65, 344–350.Google Scholar
Chilingarian, G.V. (1981) Compactional diagenesis. In: Sediment Diagenesis (Parker, A. and Sellwood, B., eds.). D. Reidel, Dodrecht, Boston and Lancaster.Google Scholar
Colten-Bradley, V. A. (1987). Role of pressure in smectite dehydration—Elfects on geopressure and smectite- illite transformation. Am. Assoc. Pet. Geol. Bull., 71, 1414–1427.Google Scholar
Cremers, A. (1968) Ionic movement in a colloidal environment. DSc Thesis, Catholic University of Louvain.Google Scholar
Dunoyer De Segonzac, G. (1970). The transformation of clay minerals during diagenesis and low-grade metamorphism: a review. Sedimentology 15, 281–346.Google Scholar
Dypvik, H. (1981) Drilling mud as a source of geochemical contamination: X-ray diffraction analyses, major and trace element analyses. Am. Assoc. Pet. Geol. Bull., 64, 744–748.Google Scholar
Dypvik, H. (1981) Clay mineral transformations in Tertiary and Mesozoic sediments from the North Sea. Am. Assoc. Pet. Geol. Bull., 67, 160–165.Google Scholar
Fritz, S.J. & Marine, I.W. (1983) Experimental support for a predictive osmotic model of clay membranes. Geochim. Cosmochim. Acta, 47, 1515–1522.Google Scholar
Fritz, S.J. (1986) Ideality of clay membranes in osmotic processes: A review. Clays Clay Miner., 34, 214–223.Google Scholar
Gast, R.G. & Spalding, G.E. (1966) Demonstration of a quantitative relationship between activity- and diffusion-coefficients of Na ion in bentonite-water systems. Proc. Int. Clay Conf., Jerusalem,, 331. Israel Program for Scientific Publications, Jerusalem.Google Scholar
Graf, D. (1982) Chemical osmosis, reverse chemical osmosis and the origin of subsurface brines. Cosmoahim. Acta, 46, 1431–1448.Google Scholar
Hall, P.L., Astill, D.M. & McConnell, J.D.C. (1986) Thermodynamic and structural aspects of the dehydration of smectites in sedimentary rocks. Clay Miner., 21, 633–648.CrossRefGoogle Scholar
Hanshaw, B.B. & Zen, E. (1965) Osmotic equilibrium and overthrust faulting. Geol. Soc. Am. Bull,, 76, 1379–1387.Google Scholar
Hanshaw, B.B. & Coplen, T.B. (1973) Ultrafiltration by compacted clay membrane—II. Sodium ion exclusion at various ionic strengths. Geochim. Cosmochim. Acta, 37, 2311–23–27.Google Scholar
Haydon, P.R. & Graf, D.L. (1986) Studies of smectite membrane behavior: temperature dependence, 20- 180°C. Geochim. Cosmochim. Acta, 50, 115–121.Google Scholar
Hedberg, W.H. (1967) Pore water chlorinities of subsurface shales.PhD Thesis, University of Wisconsin.Google Scholar
Helfferich, F. (1962) Ion Exchange. McGraw-Hill, New York.Google Scholar
Hinch, H.H. (1980) The nature of shales and the dynamics of hydrocarbon expulsion in the Gulf Coast Tertiary section. Pp. 1–18 in: Problems of Petroleum Migration (Roberts, W. H. and Cordell, R. J., editors). AAPG Studies in Geology 10.Google Scholar
Howard, J.J. & Roy, D.M. (1985) Development of layer charge and kinetics of experimental smectite alteration. Clays Clay Miner., 33, 81–88.Google Scholar
Hower, J.E., Eslinger, E.V., Hower, M.E. & Perry, E.A. (1976) Mechanism of burial metamorphism, 1; mineralogical and chemical evidence. Geol. Soc. Am. Bull., 87, 725–737.Google Scholar
Karlsson, G.W., Vollset, J.G., Bjorlykke, K. & Jorgensen, P. (1978) Changes in mineralogical composition of Tertiary sediments from North Sea wells. In: Developments in Sedimentology, 27, 281–289.Google Scholar
Kharaka, Y.K. & Smalley, W.C. (1976) Flow of water and solutes through compacted clays. Am. Assoc. Pet. Geol. Bull., 60, 973–980.Google Scholar
Kramer, J.R. (1969) Subsurface brines and mineral equilibria. Chem. Geol., 4, 37–50.Google Scholar
Lindgreen, H.. (1985) Diagenesis and primary migration in Upper Jurassic claystone source rocks in the North Sea. Am. Assoc. Pet. Geol. Bull., 69, 525–536.Google Scholar
MagaRA, K. (1975) Re-evaluation of montmorillonite dehydration as cause of abnormal pressure and hydrocarbon migration. Am. Assoc. Pet. Geol. Bull., 59, 292–302.Google Scholar
Magara, K. (1978) Compaction and Fluid Migration. Elsevier, Amsterdam, Oxford, New York.Google Scholar
Manheim, F.T. (1974) Comparative studies on extraction of sediment interstitial waters: discussion and comment on the state of interstitial water studies. Clays Clay Miner., 22, 337–343.CrossRefGoogle Scholar
Marine, I.W. & Fritz, S.J. (1981) Osmotic model to explain anomalous hydraulic heads. Water Resources Research, 17, 73–82.CrossRefGoogle Scholar
McKelvey, J.G. & Milne, I.H. (1960) The flow of salt solutions through compacted clay. Clays Clay Miner., 9, 248–259.Google Scholar
Milne, I.H., McKelvey, J.G. & Trump, R.P. (1964) Semi-permeability of bentonite membranes to brines. Am. Assoc. Pet. Geol. Bull., 48, 103–105.Google Scholar
Moncure, G.K., Lahann, R.W. & Siebert, R.M. (1984) Origin of secondary porosity and cement distribution in a sandstone/shale sequence from the Frio formation (Oligocene). Pp. 151–161 in: Clastic Diagenesis (McDonald, D. A. and Surdam, R. C., editors). AAPG Memoir 37.Google Scholar
Morton, R.A. & Land, L.S. (1987) Regional variations in formation water chemistry, Frio formation (Oligocene), Texas Gulf Coast. Am. Assoc. Pet. Geol. Bui., 71, 191–206.Google Scholar
Murthy, A.S.P. & Ferrell, R.E. (1972) Comparative chemical composition of sediment interstitial waters. Clays Clay Miner., 20, 317–321.Google Scholar
Pollastro, R.M. (1985) Mineralogical and morphological evidence for the formation of illite at the expense of illite/smectite. Clays Clay Miner., 33, 265–274.Google Scholar
Serra, O. (1984). Fundamentals of Well-Log Interpretation. 1. The Acquisition of Logging Data. Elsevier, Amsterdam, Oxford, New York.Google Scholar
Schmidt, G.W. (1973) Interstitial water composition and geochemistry of deep Gulf Coast shales and sandstones. Am. Assoc. Pet. Geol. Bull., 57, 321–337.Google Scholar
Shaw, D.B. & Weaver, C.E. (1965) The mineralogical composition of shales. J. Sed. Petrol., 35, 213–222.Google Scholar
Smith, J.E. (1977) Thermodynamics of salinity changes accompanying compaction of shaly rocks. Soc. Pet. Eng. J.Nov., 377–386.Google Scholar
SPWLA (1984) North Sea Rw Catalogue. SPWLA London Chapter, London.Google Scholar
White, D.E. (1965) Saline water of sedimentary rocks. Pp. 342–366 in: Fluids in Subsurface Environments (Young, A. and Galley, J.E., editors). AAPG Memoir 4.Google Scholar
Young, A. & Low, P.F. (1965) Osmosis in argillaceous rocks. Bull. Am. Assoc. Pet. Geol., 49, 1004–1008.Google Scholar