Long-range correlations in permeability fluctuations in porous rock

Porous media, such as sedimentary rocks, have complex permeability fluctuations arising from the physical processes that formed them. These permeability fluctuations significantly affect the flow of fluids through the rocks. We analyze data on two sandstone samples from different environments, and find that the permeability fluctuations display long-range power-law correlations characterized by an exponent H>1/2. For both samples, we find similar values of H, H0. 82-0. 90, suggesting that the permeability in porous sandstone is not spatially uncorrelated as is generally assumed. 1996 The American Physical Society.