Characterization of the Pore Structure of Porous Media Using non‐Newtonian Fluids

Abstract

AbstractWe demonstrate a simple, cheap method for pore size characterization of porous media that generates a distribution of pore radii for improved flow and transport modeling. The new method for pore structure characterization utilizes recent theoretical developments in non‐Newtonian fluids. Numerical evaluations and validations with synthetic porous media showed potential for obtaining a distribution of effective pore radii and their contribution to total flow only by complementing water with non‐Newtonian fluids in saturated infiltration experiments. To demonstrate this ability on real sands, a series of one‐dimensional column experiments was conducted with varying porous medium packings, including Accusands and a polydisperse sand/glass bead mixture. For each packing, distilled water and varying concentrations of guar and xanthan gum were injected over a range of flow rates and pressure gradients. The model‐generated pore radii were compared with pore radius distributions measured by X‐ray microcomputed tomography (μCT), with results demonstrating good agreement between the model and μCT data. Simulations of saturated water flow and drainage curves using model‐generated pore radii compared favorably to experimental data, with errors typically between 2% and 10% for single‐phase flow and approaching the error of the μCT measured radius distributions for the drainage curves.