Numerical simulation of non-Newtonian fluid flow through a rock scanned with high resolution X-ray micro-CT

Most of the pore-scale models are concerned with Newtonian fluid 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). The numerical model is based on the resolution of the mass and momentum conservation equations in conjunction with an adaptive meshing technique used to generate the mesh along with the appropriate boundary conditions to compute the porous media permeability. To describe the fluid rheology, a concentration-dependent power-law viscosity model in line with the experimental measurement of the fluid rheology is proposed. The model is first applied at isothermal condition to 2 benchmark rocks samples, a sandstone and a carbonate. The implemented FVM technique shows a good agreement with the Lattice Boltzmann Method (LBM). Subsequently, at nonisothermal conditions, the numerical simulation is carried out where the effective mobility is introduced to make a sensitivity study at different operating conditions and fluid rheology. The normalized mobility on the polymer concentration leads to a master curve while the flow rate displays a contrast between the carbonate and the sandstone.