Effects of Grain Size on Deformation in Porous Media

The solid system in deformable porous media undergoes deformation with the flow of fluid. In this paper, in order to study the micro-mechanism of the deformation, the solid system in the porous media is represented by a pack of spherical particles and simulated by discrete element method. The fluid system in the porous media is also simulated by computational fluid dynamics. To consider the fluid-particle interactions in the porous media, the above techniques are coupled and applied for simulating the solid deformation and fluid flow. Different models consisting of different particle sizes are studied in dry (without the presence of fluid) and wet states (with the flow of fluid). The results show that with the decrease in the particle size, the solid deformation declines, which imitates the actual deformation in the porous media. More importantly, the comparison between the dry and wet models indicates that the effect of the fluid on the particle system is diminishing with the smaller packed particles. The solid deformation tendency is quantified by the reduction in the values of some micro-mechanical properties, such as permeability (absolute and relative), porosity and pore-size distribution.