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Observations of heterogeneous pore pressure distributions in clay-rich materials

Published online by Cambridge University Press:  05 July 2018

R. J. Cuss ,
J. F. Harrington ,
C. C. Graham ,
S. Sathar  and
A. E. Milodowski
R. J. Cuss*
Affiliation:
British Geological Survey, Keyworth, Nottingham NG12 5GG, UK
J. F. Harrington
Affiliation:
British Geological Survey, Keyworth, Nottingham NG12 5GG, UK
C. C. Graham
Affiliation:
British Geological Survey, Keyworth, Nottingham NG12 5GG, UK
S. Sathar
Affiliation:
British Geological Survey, Keyworth, Nottingham NG12 5GG, UK
A. E. Milodowski
Affiliation:
British Geological Survey, Keyworth, Nottingham NG12 5GG, UK
*
*E-mail: rjcu@bgs.ac.uk
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Abstract

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The concept of effective stress is one of the basic tenets of rock mechanics where the stress acting on a rock can be viewed as the total stress minus the pore water pressure. In many materials, including clay-rich rocks, this relationship has been seen to be imperfect and a coefficient (χ) is added to account for the mechanical properties of the clay matrix. Recent experimental results during the flow testing (both gas and water) of several rocks (Callovo-Oxfordian claystone, Opalinus Clay, Boom Clay) and geomaterials (bentonite, kaolinite) has given evidence for stable high pressure differentials. The design of the experiments allows multiple measurements of pore pressure, which commonly shows a complex distribution for several different experimental geometries. The observed stable high pressure differentials and heterogeneous pore pressure distribution makes the describing of stress states in terms of effective stress complex. Highly localized pore pressures can be sustained by argillaceous materials and concepts of evenly distributed pore pressures throughout the sample (i.e. conventional effective stress) do not fit many clay-rich rocks if the complexities observed on the micro-scale are not incorporated, especially when considering the case of gas flow.

Keywords

bentonitecallovo-oxfordian claystonekaoliniteopalinus claypressuremechanical propertiesargillaceous rockseffective stress
Type
Research Article
Information
Mineralogical Magazine , Volume 76 , Issue 8 , December 2012 , pp. 3115 - 3129
Creative Commons
Creative Common License - CCCreative Common License - BY
© [2012] The Mineralogical Society of Great Britain and Ireland. This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY) licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2012

References

Atkinson, J.H. and Bransby, P.L. (1978) The Mechanics of Soils: An Introduction to Critical State Soil Mechanics. McGraw-Hill, New York.Google Scholar
Biot, M.A. (1941) General theory of three-dimensional consolidation. Journal of Applied Physics, 12, 155–164.CrossRefGoogle Scholar
Burrus, J. (1998) Overpressure models for clastic rocks, their relation to hydrocarbon expulsion: A critical reevaluation. Pp. 35–63.in: Abnormal Pressures in Hydrocarbon Environments (B.E. Law G.F. Ulmishek and V.I. Slavin, editors). AAPG Memoir 70. The American Association of Petroleum Geologists, Tulsa, Oklahoma, USA.Google Scholar
Byerlee, J.D. (1975) The fracture strength and frictional strength of Weber Sandstone. International Journal of Rock Mechanics and Mining Sciences, 12, 1–4.CrossRefGoogle Scholar
Cuss, R.J. (1999) An experimental investigation of the mechanical behaviour of sandstones with reference to borehole stability. Unpublished PhD thesis, University of Manchester, Manchester, UK.Google Scholar
Cuss, R.J., Harrington, J.F. and Noy, D.J. (2010) Large scale gas injection test (Lasgit) performed at the Ä spöHard Rock Laboratory. Summary report 2008.Google Scholar
Svensk Kärnbränslehantering AB (SKB) Technical Report TR-10–38. SKB, Stockholm, Sweden, 109 pp.Google Scholar
Cuss, R.J., Harrington, J.F., Noy, D.J., Wikman, A. and Sellin, P (2011a) Large scale gas injection test (Lasgit): results from two gas injection tests. Physics and Chemistry of the Earth, 36, 1729–1742.CrossRefGoogle Scholar
Cuss, R.J., Milodowski, A.E. and Harrington, J.F. (2011b) Fracture transmissivity as a function of normal and shear stress: first results in Opalinus clay. Physics and Chemistry of the Earth, 36, 1960–1971.Google Scholar
Gautschi, A. (2001) Hydrogeology of a fractured shale (Opalinus Clay): implications for deep geological disposal of radioactive wastes. Hydrogeology Journal, 9, 97–107.CrossRefGoogle Scholar
Handin, J., Hager, R.V. Jr, Friedman, M. and Feather, J.N. (1963) Experimental deformation of sedimentary rocks under confining pressure: pore pressure tests. Bulletin of the American Association of Petroleum Geologists, 47, 717–755.Google Scholar
Harrington, J.F., Horseman, S.T. and Noy, D.J. (2003) Measurements of water and gas flow in Opalinus Clay using a novel guard-ring methodology. British Geological Survey Technical Report CR/03/32, 35 pp.Google Scholar
Harrington, J.F., de la Vaissiére, R., Noy, D.J., Cuss, R.J. and Talandier, J. (2012) Gas flow in Callovo- Oxfordian claystone (COx): results from laboratory and field-scale measurements. Mineralogical Magazine, 76, 3303–3318.CrossRefGoogle Scholar
Hubbert, M.K., and Rubey, W.W. (1959) Role of fluid pressure in mechanics of overthrust faulting: 1 - mechanics of fluid-filled porous solids and its application to overthrust faulting. Geological Society of America Bulletin, 70, 115–166.CrossRefGoogle Scholar
Kwon, O., Kronenberg, A.K., Gangi, A.F. and Johnson, B. (2001) Permeability of Wilcox Shale and its effective pressure law. Journal of Geophysical Research, B, Solid Earth and Planets, 106, 19,339–19, 353.Google Scholar
Pearson, F.J., Scholtis, A., Gautschi, A., Baeyens, A., Bradbury, M. and Degueldre, C. (1999) Chemistry of porewater. Pp. 129–147.in: Mont Terri Rock Laboratory: results of the hydrogeological, geochemical and geotechnical experiments performed in 1996 and 1997 (M. Thury and P. Bossart, editors). Geological Report, 23. Swiss National Hydrological and Geological Survey, Bern.Google Scholar
Sathar, S., Reeves, H.J., Cuss, R.J. and Harrington, J.F. (2012) The role of stress history on the flow of fluids through fractures. Mineralogical Magazine, 76, 3165–3177.CrossRefGoogle Scholar
Schofield, A. and Wroth, C.P. (1968) Critical State Soil Mechanics. McGraw-Hill, London, 310 pp. Terzaghi, K. (1943) Theoretical Soil Mechanics. John Wiley, New York.Google Scholar
Wenk, H.-R., Voltolini, M., Mazurek, M., Van Loon, L.R. and Vinsot, A. (2008) Preferred Orientations and Anisotropy in Shales: Callovo-Oxfordian Shale (France) and Opalinus Caly (Switzerland). Clays and Clay Minerals, 56, 285–306.CrossRefGoogle Scholar
Wood, D.M. (1990) Soil Behaviour and Critical State Soil Mechanics. Cambridge University Press, Cambridge, UK, 462 pp.Google Scholar