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Linear estimation of flux sensitivity to uncertainty in porous media

Published online by Cambridge University Press:  11 March 2015

A. J. Evans*
Affiliation:
BP Institute, University of Cambridge, Madingley Rise, Madingley Road, Cambridge CB3 0EZ, UK
C. P. Caulfield
Affiliation:
BP Institute, University of Cambridge, Madingley Rise, Madingley Road, Cambridge CB3 0EZ, UK Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, UK
Andrew W. Woods
Affiliation:
BP Institute, University of Cambridge, Madingley Rise, Madingley Road, Cambridge CB3 0EZ, UK
*
Email address for correspondence: aje47@cam.ac.uk

Abstract

We derive an integral expression for the flux of a single-phase fluid through a porous medium with prescribed boundary conditions. Taking variations with respect to the parameters of a given permeability model yields an integral expression for the sensitivity of the flux. We then extend the method to consider linear changes in permeability. This yields a linearised flux expression which is independent of changes in the pressure field that result from the changes in the permeability. For demonstration purposes, we first consider an idealised layered porous medium with a point source and point sink. We show how the effects of changes in permeability are affected by the position of the source and sink relative to the layered structure as well as the layer height and orientation of the layered structure. The results demonstrate that, even in a simple porous system, flux estimates are sensitive to the way in which the permeability is represented. We derive relationships between the statistical moments of the flux and of the permeability parameters which are modelled as random variables. This allows us to estimate the number of permeability parameters that should be varied in a fully nonlinear calculation to determine the variance of the flux. We demonstrate application of the methods to permeability fields generated through fast Fourier transform and kriging methods. We show that the linear estimates for the variability in flux show good agreement with fully nonlinear calculations for sufficiently small standard deviations in the underlying permeability.

Type
Papers
Copyright
© 2015 Cambridge University Press 

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References

Bear, J. 1972 Dynamics of Fluids in Porous Media. Dover.Google Scholar
Black, T. C. & Freyberg, D. L. 1990 Simulation of one-dimensional correlated fields using a matrix-factorization moving average approach. Math. Geol. 22, 3962.Google Scholar
Borgman, L., Taheri, M. & Hagan, R. 1984 Three-dimensional frequency-domain simulations of geological variables. In Geostatistics for Natural Resource Characterization (ed. Verly, G., David, M., Journel, A. G. & Marechal, A.), pp. 517541. Springer.Google Scholar
Chilés, J. P. & Delfiner, P. 1999 Geostatistics: Modeling Spatial Uncertainty. Wiley.CrossRefGoogle Scholar
Christie, M. A. 1996 Upscaling for reservoir simulation. J. Petrol. Tech. 48, 10041010.Google Scholar
Cushman, J. H., Bennethum, L. S. & Hu, B. X. 2002 A primer on upscaling tools for porous media. Adv. Water Resour. 25, 10431067.CrossRefGoogle Scholar
Davis, M. W. 1987 Production of conditional simulations via the LU triangular decomposition of the covariance matrix. Math. Geol. 19, 9198.Google Scholar
Desbarats, A. J. 1992 Spatial averaging of hydraulic conductivity in three-dimensional heterogeneous porous media. Math. Geol. 24, 249267.Google Scholar
Deutsch, C. V. 1996 Correcting for negative weights in ordinary kriging. Comput. Geosci. 22, 765773.CrossRefGoogle Scholar
Dietrich, C. R. & Newsam, G. N. 1993 A fast and exact method for multidimensional Gaussian stochastic simulations. Water Resour. Res. 29, 28612869.Google Scholar
Farmer, C. L. 2002 Upscaling: a review. Intl J. Numer. Meth. Fluids 40, 6378.Google Scholar
Fiori, A., Dagan, G. & Jankovic, I. 2013 Upscaling of flow in heterogeneous porous formations: critical examination and issues of principle. Adv. Water Resour. 51, 6785.Google Scholar
Gavalas, G. R., Shah, P. C. & Seinfeld, J. H. 1976 Reservoir history matching by Bayesian estimation. SPE J. 16, 337350.Google Scholar
Gerritsen, M. G. & Durlofsky, L. J. 2005 Modeling fluid flow in oil reservoirs. Annu. Rev. Fluid Mech. 37, 211238.Google Scholar
Jahn, F., Cook, M. & Graham, M. 2008 Hydrocarbon Exploration & Production, chap. 14, Elsevier.Google Scholar
King, M. J., King, P. R., McGill, C. A. & Williams, J. K. 1995 Effective properties for flow calculations. Trans. Porous Med. 20, 169196.Google Scholar
King, P. R. & Smith, P. J. 1988 Generation of correlated properties in heterogeneous porous media. Math. Geol. 20, 863877.Google Scholar
Kostov, C. & Dubrule, O. 1986 An interpolation method taking into account inequality constraints: II. Practical approach. Math. Geol. 18, 5373.Google Scholar
Krige, D. G. 1951 A statistical approach to some basic mine valuation problems on the Witwatersrand. J. Chem. Met. Mining Soc. South Africa 52, 119139.Google Scholar
Lophaven, S. N., Nielsen, H. B. & Søndergaard, J.2002 DACE a MATLAB kriging toolbox. Informatics and Mathematical Modelling, IMM-TR-2002-12.Google Scholar
Mantoglou, A. & Wilson, J. L. 1982 The turning bands methods for simulation of random fields using line generation by a spectral method. Water Resour. Res. 18, 13791394.Google Scholar
Matheron, G. 1971 The Theory of Regionalized Variables and its Applications, Les Cahiers du Centre de Morphologie Mathematique de Fontainebleu, vol. 5. Ecole Nationale Superieure de Mines de Paris.Google Scholar
Renard, Ph. & de Marsily, G. 1997 Calculating equivalent permeability: a review. Adv. Water Resour. 20, 253278.CrossRefGoogle Scholar
Wen, X. & Gómez-Hernández, J. 1996 Upscaling hydraulic conductivities in heterogeneous media: an overview. J. Hydrol. 183, ixxxxii.Google Scholar
Wu, X. H., Efendiev, Y. & Hou, T. Y. 2002 Analysis of upscaling absolute permeability. J. Discrete Continuous Dyn. Syst. B 2, 185204.Google Scholar
Yilmaz, Ö. 2001 Seismic Data Analysis: Processing, Inversion, and Interpretation of Seismic Data. vol. 2. SEG Books.Google Scholar