Predicting Shear-Thinning Fluid Flows in Porous Media Using Pore Network Modeling: Simulations and Experimental Validation

Pore network modeling (PNM) allows for a major reduction in computational cost when performing pore-scale flow simulations in porous media. Despite the increasing use of such a modeling approach, the studies tackling the simulation of the flow of non-Newtonian fluids are scarce and lack experimental validation. This represents a stumbling block due to nascent state of this field. Moreover, the choice of pore and throat shapes is often arbitrary and its effects on the accuracy of the numerical simulations have not been systematically evaluated. Previous research showed that shear-thinning fluids are deeply sensitive to the morphology of flow channels. The present work deals with the modeling of the flow of Newtonian and shear-thinning fluids through packs of spherical beads, with the aim to develop a reliable procedure to predict such flows based on PNM. A set of PNM flow simulations were performed using different pore morphologies, and the results were compared to previous experimental data. The effects of the rheological parameters and the size of the spheres were extensively evaluated. In this manner, the most suitable shape and geometry was identified and the differences between the results for Newtonian and non-Newtonian fluids analyzed. Furthermore, the permeability value computed by PNM and direct numerical simulations was compared to ensure the representativeness of the extracted networks. The results showed that PNM provides accurate predictions of the flow of both Newtonian and shear-thinning fluids provided that the appropriate pore shape is used.