Scaling of Imbibition Front Dynamics in Heterogeneous Porous Media

Abstract

Abstract We report a quantitative study on the dynamics of countercurrent imbibition in fractured rock samples with the application of CO 2 geosequestration, as the rock matrix is saturated with CO 2 and brine exists in the adjacent microfracture. Direct pore‐scale simulations of spontaneous and forced imbibition in a three‐dimensional heterogeneous porous matrix enable us to capture the effect of microscopic properties on the imbibition dynamics as these pore‐level descriptions are ignored in the existing coarse‐grained models. We have established new scaling classes for the propagation of the center of mass of the imbibition front and fluid‐fluid interface broadening. It has become evident that the wettability is a major factor which leads to anomalies in these scaling laws. While the governing capillarity under the water‐wet condition induces fast roughening dynamics of the interface, the adverse effect of capillary pressure under the intermediate‐wet condition leads to a damping effect on the imbibition front fluctuations.