Transport in sandstone: A study based on three dimensional microtomography

Abstract

High resolution imaging of the microstructure of Fontainebleau sandstone allows a direct comparison between theoretical calculations and laboratory measurements. While porosity, pore-volume-to-surface ratio, permeability, and end point relative permeability are well predicted by our calculations, we find that electrical resistivity and wetting phase residual saturation are both overestimated. Introduction Transport in porous media is of importance in biology, chemical engineering, earth and environmental sciences, materials science, and physics [Adler, 1992; Cushman, 1990]. Because real porous media are usually highly disordered, most recent work on transport theory has been based on synthetic model systems, such as random sphere packs [Adler, 1992; Schwartz et al., 1993]. Although instructive, such studies are not easily applied to the understanding of real materials. High resolution synchrotron microtomography [Flannery et al., 1987; Kinney et al., 1993; Schwartz et al., 1994; $panne eta!., 1994 Coles et al., 1995] however, may be used to map the pore space of a real material. Here we study the geometrical and transport properties of three-dimensional tomographic reconstructions of several samples of Fontainebleau sandstone. We compare numerical calculations to laboratory measurements made on samples approximately an order of magnitude larger in linear dimension. We obtain a heirarchy of results, presented in Table 1. Geometrical properties are accurately estimated by our calculations, as is the permeability to single-phase flow. The computed electrical conductivity, on the other hand, underestimates the experimental results. Studies of immiscible displacement by a non-wetting fluid give mixed results. While our endpoint relative permeability calculation is in good •Schlumberger-Doll Research, Ridgefield, CT. agreement with the measured data, the corresponding saturation is less satisfactory. AUZERAIS ET AL.: TRANSPORT IN SANDSTONE 707 2.0 ' -1.0 ß size 56 [] size 112 ¸ size 224 ß ß •e ß ß ß ee ß ß eee ß F. M Auzerais, T. S. Ramakrishnan, and L. M. Schwartz, Schlumberger-Doll Research, Ridgefield, CT 06877 J. Dunsmuir, Exxon Research and Engineering Company, Route 22 East, Annandale, NJ 08801 B. Ferr•ol, Elf Aquitaine,

Imaging of colloidal deposits in granular porous media by X‐ray difference micro‐tomography

“…[5] X-ray computed microtomography (X-CMT) performed at a synchrotron research center provides the ability to obtain three-dimensional, in situ observations of the internal structure of materials with micron-scale resolution [Auzerais et al, 1996;Flannery et al, 1987;Li et al, 2006;Spanne et al, 1994;Wildenschild et al, 2005]. The distributions of individual elements can be determined by performing difference tomography, where the X-rays used to image the sample are selected to be just below and above the absorption edge of the element of interest.…”

Probing pores using elementary quantum mechanics

“…8 The complex 3D pores are represented as coupled cluster of micron length scale cubes in which a large number of random walkers (typically 10 4 − 10 5 in numbers) are deployed to simulate a variety of MR measurements. For M α , we obtain the internal field by numerically evaluating dipole contributions from all surrounding chambers.…”

Pore-scale mass and reactant transport in multiphase porous media flows

“…Several recent studies (see for example Auzerais et al 1996;Coles et al 1998;Schaap et al 2007;Sukop et al 2008) compared their numerical calculations with digital images of natural samples obtained by X-ray tomography and found a good agreement at both the microscale (location of the fluid phases) and the macroscale (capillary pressure-saturation conditions).…”