Invasion percolation in correlated porous media

Invasion percolation is studied on a correlated porous network described through a site-bond model which has proven to be useful for the characterization of real porous media. It is shown how the correlation degree affects the advance velocity of the invasion front, the fraction of invaded sites and bonds and the number of islands of trapped defender fluid (which are completely surrounded by invaded elements) and their size distribution. The fractal dimension of the percolating cluster, on the other hand, does not seem to be influenced by the correlation degree. As a novel result, a characteristic correlation length is found to exist which maximizes the mean invasion velocity.