Dynamics of viscous penetration in percolation porous media - art. no. 051403

We investigate the dynamics of viscous penetration in two-dimensional perco lation networks at criticality for the case in which the ratio between the viscosities of displaced and injected fluids is very large. We report exten sive numerical simulations that indicate that the scaling exponents for the breakthrough time distribution are the same as the previously reported val ues computed for the case of unit viscosity ratio. Our results are consiste nt with the possibility that viscous displacement through critical percolat ion networks constitutes a single universality class, independent of the vi scosity ratio. We also find that the distributions of mass and breakthrough time of the invaded clusters have the same scaling form, but with differen t critical exponents.