The effect of morphological disorder on viscous fingers and diffusion-limited aggregates in a porous medium

Abstract

The authors investigate the growth of viscous fingers (VF) and diffusion-limited aggregates (DLA) in a disordered porous medium. They propose that the DLA model and VF are not equivalent in a porous medium with topological disorder as represented by a percolation system and suggest new universality classes for VF and DLA in such media. They also present evidence that, for a wide class of porous media with geometrical disorder (i.e. with pores of random sizes), the DLA model and VF are not equivalent, even though they have often been characterised by approximately the same fractal dimension. Moreover, VF appear to be sensitive to the local properties of the medium such as the pore size distribution. Therefore, the DLA model cannot be used to simulate VF in disordered porous media and to predict the efficiency of the displacement process.