X-ray tomography measurements of power-law cluster size distributions for the nonwetting phase in sandstones

Stefan Iglauer1,*, Stefano Favretto2,†, Gregorio Spinelli2,‡, Gianni Schena2,§, and Martin J. Blunt1,** 1Department of Earth Science and Engineering, Imperial College London, London SW7 2AZ, United Kingdom 2Department of Civil Engineering and Environment Engineering, University of Trieste, 34127 Trieste, Italy Received 6 June 2010; published 15 November 2010 Three-dimensional images of sandstones containing residual nonwetting phase were obtained using synchrotron x-ray tomography with a resolution of approximately 9 μm. We determined the size distribution of disconnected nonwetting phase clusters (ganglia); the number of ganglia of size s is N(s)∼s−τ with τ=2.05. The vast majority of the residual phase was contained in large clusters, spanning many pores. This result implies that we have clusters of all sizes providing a huge surface area for geochemical reactions and dissolution while allowing mobilization of the residual phase during improved oil recovery in hydrocarbon reservoirs and carbon dioxide storage in aquifers. © 2010 The American Physical Society URL: http://link.aps.org/doi/10.1103/PhysRevE.82.056315 DOI: 10.1103/PhysRevE.82.056315 PACS: 47.56.+r, 91.60.Np, 47.55.nb, 81.70.Tx