Role of size correlations in fluid displacement in porous solids

A 3-dimensional simulation of fluid displacement in a disordered porous sol id is performed. The solid heterogeneities are characterized by two pore si ze distributions in the context of the dual site-bond model (DSBM). It is s hown how invasion patterns and relevant quantities in invasion percolation are affected by the disordered porous matrix confirming and also contrastin g previous results in 2-dimensional networks. Deeper understanding of the p roblem is achieved by allowing the presence of anisotropy in the porous spa ce.