Pore-Scale Modeling of Non-Newtonian Fluid Flow Through Micro-CT Images of Rocks

Most of the pore-scale models are concerned with Newtonian fluid flow due to its simplicity and the challenge posed by non-Newtonian fluid. In this paper, we report a non-Newtonian numerical simulation of the flow properties at pore-scale by direct modeling of the 3D micro-CT images using a Finite Volume Method (FVM). To describe the fluid rheology, a concentration-dependent power-law viscosity model, in line with the experimental measurements of the fluid rheology, is proposed. The model is first applied to a single-phase flow of Newtonian fluids in 2 benchmark rocks samples, a sandstone and a carbonate. The implemented FVM technique shows a good agreement with the Lattice Boltzmann Method (LBM). Subsequently, adopting a non-Newtonian fluid, the numerical simulation is used to perform a sensitivity study on different fluid rheological properties and operating conditions. The normalized effective mobility variation due to the change in polymer concentration leads to a master curve while the flow rate displays a contrast between carbonate and sandstone rocks.