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The effect of organic acids on the dissolution of K-feldspar under conditions relevant to burial diagenesis

Published online by Cambridge University Press:  05 July 2018

J. Bevan
Affiliation:
Department of Geology, University of Nottingham, Nottingham NG7 2RD, UK
D. Savage
Affiliation:
Department of Geology, University of Nottingham, Nottingham NG7 2RD, UK

Abstract

The mechanism by which secondary porosity in sandstone reservoirs is produced is poorly understood. Previous hypotheses to account for the increased dissolution of framework silicates have invoked the introduction of acidic and/or organic-rich fluids capable of complexing metals. In order to evaluate the relative effects of these factors, the rates of K-feldspar dissolution have been measured at 70°C and 95°C, at pH values of 1, 4, and 9, with and without oxalic acid, at a total pressure of 50 MPa, using direct sampling autoclaves. The presence of oxalic acid increased the dissolution rate of Kfeldspar at pH 4 and 9, but decreased the rate at pH 1 at both temperatures. The maximum increase in dissolution rate was observed at pH 4, 95°C by a factor ∼4. In oxalic-free experiments, the rate of dissolution increased an order of magnitude with each unit decrease in pH in the pH regime 1–4. In the presence of oxalic acid, this dependency of dissolution upon pH decreased to approximately an order of magnitude increase with each decrease in pH by 2pH units. The dissolution process was observed to be stoichiometric under all conditions, indicating that the mechanism by which rates are increased was not due to preferential complexation of aluminium, but rather by an increase in the overall solubility of feldspar in the neutral pH region. This regime of increased rate of reaction of feldspar coincides with that expected to be naturally buffered by the introduction of organic acids into a sandstone reservoir system.

Type
Petrology and Geochemistry
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1989

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Footnotes

*

Now at Enterprise Oil, Griffin House, The Strand, London WC2, UK

Fluid Processes Research Group, British Geological Survey, Keyworth, Notts NG12 5GG, UK

References

Aagaard, P. and Helgeson, H. C. (1982) Am. J. Sci. 282, 237-85.CrossRefGoogle Scholar
Bath, A. H., Milodowski, A. E. and Strong, G. E. (1987) In Fluid flow in sedimentary basins and aquifers (Goff, J. C. and Williams, B. P. J., eds.). Geol. Soc. Spec. Pub. 34, 127-40.Google Scholar
Bjorlykke, K. (1984) In Clastic diagenesis (MacDonald, D. A. and Surdam, R. C., eds.). Am. Assoc. Petrol. Geol. Memoir 37, 277-86.Google Scholar
Burley, S. D. (1986) Clay Min. 21, 64-94.CrossRefGoogle Scholar
Busenberg, E. and Clemency, C. V. (1976) Geochim. Cosmochim. Acta 40, 41-50.CrossRefGoogle Scholar
Carothers, W. and Kharaka, Y. K. (1978) Bull. Am. Assoc. Petrol. Geol. 62, 2441-53.Google Scholar
Chou, L. and Wollast, R. (1984) Geochim. Cosmochim. Acta 48, 2205-17.CrossRefGoogle Scholar
Chou, L. and Wollast, R. (1985) Am. J. Sci. 285, 963-93.CrossRefGoogle Scholar
Curtis, C. (1978) J. Geol. Soc. Lond. 135, 107-17.CrossRefGoogle Scholar
Curtis, C. (1983) In Petroleum Geochemistry and Exploration of Europe (Brooks, J., ed.). Geol. Soc. Lond. Spec. Publ. 12, 113-25.Google Scholar
Dibble, W. E. Jr. and Potter, J. M. (1982) Effect of fluid flow on geochemical processes. Soc. Petrol. Engineers 57th Annual Meeting, New Orleans.CrossRefGoogle Scholar
Edman, J. D. and Surdam, R. C. (1986) In Roles of Organic Matter in Sediment Diagenesis (Gautier, D., ed.). SEPM Spec. Publ. 38, 85110.CrossRefGoogle Scholar
Eyring, H. (1935) J. Chem. Phys. 3, 107-15.CrossRefGoogle Scholar
Giles, M. R. and Marshall, J. D. (1986) Marine Petrol. Geol. 3, 243-55.CrossRefGoogle Scholar
Goodchild, M. W. and Whitaker, J. H. McD. (1986) Clay Min. 21, 45-77.CrossRefGoogle Scholar
Helgeson, H. C., Murphy, W. M. and Aagaard, P. (1984) Geochim. Cosmochim. Acta 48, 2405-32.CrossRefGoogle Scholar
Holdren, G. R. and Berner, R. A. (1979) Ibid. 43, 1161-71.Google Scholar
Holdren, G. R. and Speyer, P. M. (1985) Am. J. Sci. 285, 994-1026.CrossRefGoogle Scholar
Holdren, G. R. and Speyer, P. M. (1986) In Rates of chemical weathering o frocks and minerals (Colman, S. M. and Dethier, D. P., eds.). Academic Press Inc., Orlando, Florida, 6181.Google Scholar
Huang, W. H. and Kiang, W. C. (1972) Am. Mineral. 57, 1849-59.Google Scholar
Huang, W. H. and Longo, J. M. (1987) Effect of organic acids on feldspar dissolution. Outline of a paper presented at a GSA Conference, Oxnard, California.Google Scholar
Irwin, H. and Hurst, A. R. (1983) In Petroleum Geochemistry and Exploration of Europe (Brooks, J., ed.). Geol. Soc. Lond. Spec. Publ. 12, 127-46.Google Scholar
Kharaka, Y. K., Law, L. M. and Carothers, W. W. (1986) In Roles of Organic Matter in Sediment Diagenesis (Gautier, D., ed.). SEPM Spec. Publ. 38, 111-22.CrossRefGoogle Scholar
Knauss, K. G. and Wolery, T. J. (1986) Geochim. Cosmochim. Acta 50, 2481-97.CrossRefGoogle Scholar
Lagache, M. (1965) Bull. Soc. fr. Min. Crist. 88, 223-53.Google Scholar
Lasaga, A. C. (1981) In Kinetics of geochemical processes (Lasaga, A. C. and Kirkpatrick, R. J., eds.). Reviews in Mineralogy 8, 1-67. Min. Soc. Am., Washington.CrossRefGoogle Scholar
Lasaga, A. C. (1984) J. Geophys. Res. 89, 4009-25.CrossRefGoogle Scholar
Lundegard, P. D., Land, L. S. and Galloway, W. E. (1984) Geology 12, 399-402.2.0.CO;2>CrossRefGoogle Scholar
Manley, E. P. and Evans, L. J. (1986) Soil Sci. 141, 106-12.CrossRefGoogle Scholar
Mast, M. A. and Drever, J. I. (1987) Geochim. Cosmochim. Acta 51, 2559-68.CrossRefGoogle Scholar
Meshri, I. (1986) In Roles of Organic Matter in Sediment Diagenesis (Gautier, D., ed.). SEPM Spec. Publ. 38, 123-8.CrossRefGoogle Scholar
Moncure, G. K., Lahann, R. W. and Siebert, R. M. (1984) In Clastic diagenesis (MacDonald, D. A. and Surdam, R. C., eds.). Am. Assoc. Petrol. Geol. Mem. 37, 151-61.Google Scholar
Murphy, W. M. and Helgeson, H. C. (1987) Geochim. Cosmochim. Acta 51, 3137-53.CrossRefGoogle Scholar
Perrin, D. D. and Dempsey, B. (1974) Buffers for pH and metal ion control. John Wiley and Sons, New York.Google Scholar
Potter, J. M., Pohl, D. C. and Rimstidt, J. D. (1987) In Hydrothermal Experimental Techniques (Ulmer, G. C. and Barnes, H. L., eds.). John Wiley and Sons, New York, 240-60.Google Scholar
Rimstidt, J. D. and Dove, P. M. (1986) Geochim. Cosmochim. Acta 50, 250-16.CrossRefGoogle Scholar
Robinson, B. A. (1982) LA-9404-T Thesis. Massachusetts Institute of Technology, Cambridge, MA. Los Alamos National Library, New Mexico.Google Scholar
Scherer, M. (1987) Bull. Am. Assoc. Petrol. Geol. 71, 485-91.Google Scholar
Schmidt, V. and McDonald, D. A. (1979) In Aspects of Diagenesis (Scholle, P. A. and Schluger, P. R., eds.). SEPM Spec. Publ. 26, 175207.CrossRefGoogle Scholar
Seyfried, W. E., Gordon, P. C. and Dickson, F. W. (1979) Am. Mineral. 64, 646-9.Google Scholar
Seyfried, W. E., Janecky, D. R. and Berndt, M. E. (1987) In Hydrothermal Experimental Techniques (Ulmer, G. C. and Barnes, H. L., eds.). John Wiley and Sons, New York, 216-39.Google Scholar
Siebert, R. M., Moncure, G. K. and Lahann, R. W. (1984) In Clastic diagenesis (MacDonald, D. A. and Surdam, R. C., eds.). Am. Assoc. Petrol. Geol. Mem. 37, 163-75.Google Scholar
Siegel, D. I. and Pfannkuch, H. O. (1984) Geochim. Cosmochim. Acta 48, 197-201.CrossRefGoogle Scholar
Surdam, R. C., Boese, S. W. and Crossey, L. J. (1984) In Clastic diagenesis (MacDonald, D. A. and Surdam, R. C., eds.). Am. Assoc. Petrol. Geol. Mem. 37, 127-51.Google Scholar
Surdam, R. C. and Crossey, L. J. (1985) Phil. Trans. Roy. Soc. London A315, 135-56.Google Scholar
Wolery, T. J. (1986) Lawrence Livermore Nat. Lab. Rep. UCRL 94221.Google Scholar
Wollast, R. (1967) Geochim. Cosmochim. Acta 31, 635-48.CrossRefGoogle Scholar