Single-Phase Polymer Flow in Porous Media: Numerical Model for Experimental Planning and Analysis

Abstract

Polymer flow in porous media is relevant in the oil industry since there are uses for polymeric solutions in drilling fluids and enhanced oil recovery, for example. To implement these processes, several experiments are needed to characterize the solution and its interactions with the medium. However, polymer flooding experiments offer challenges in planning and analyzing. The objective of this work is to develop and implement a model to simulate polymer core flooding experiments. This is achieved by modeling a system with two coupled partial differential equations: hydraulic diffusion and reaction-advection-dispersion of polymer, and five constitutive equations to represent: non-Newtonian viscosity, in-situ shear rate, adsorption, permeability reduction, and inaccessible pore volume. A dimensionless numerical model is developed using finite differences discretization. The solution is achieved in an implicit fashion for both pressure and concentration, but all coupled phenomena are evaluated explicitly. Validation of the model is achieved by comparison with analytical solutions, established for simplified situations. A broad sensitivity analysis is performed. The analyzed variables are polymer concentration, injection rate, permeability, diffusion coefficient, inaccessible pore volume, adsorption, residual resistance factor and non-Newtonian viscosity. Additionally, a space-time discretization criterion is developed to minimize approximation errors.