Fluid Injection Experiments in 2D Porous Media

A series of injection experiments was conducted in a He le-Shaw cell-like radial-flow device filled with fine sands to better understand the fundamental failure/flow mechanisms when dense granular media were invaded and displaced by a fluid. Both aqueous glycerin solutions and polyacrylamide solutions were used as the invading fluid. The experimental findings suggest that as the injection velocity and fluid viscosity (or polymer concentration) increase, there is a transition from the solid-like to the fluid-like behavior in the granular media response. On the basis of the patterns of grain displacements and fluid flow, four distinct failure/flow regimes can be identified from the experiments: the simple radial-flow regime, the infiltration- or leakoff-dominated regime, the grain-displacement-dominated regime, and the viscous-fingering-dominated regime. These failure/flow patterns emerge as a result of competition among various forms of energy dissipation (i.e., viscous dissipation through flow in porous media, dissipation by means of grain displacements, and viscous dissipation through flow in thin channels).