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

Vitor H. S. Ferreira¹; Rosangela B. Z. L. Moreno¹

¹ University of Campinas

doi:10.20906/CPS/CILAMCE2015-0450

Resumo

Polymer flow in porous media is especially relevant in the oil industry since there are uses for polymeric solutions in drilling fluids and enhanced oil recovery, for example. In order to implement the processes, several experiments are needed to characterize the solution and its interactions with the porous medium. However, polymer flooding in porous media experiments offer challenges in planning and data analyzing. The main objective of this work is to develop a computer algorithm to aid the experimentalist in these cases. This is achieved by modeling a system with two coupled partial differential equations: hydraulic diffusion and reaction-advection-dispersion of a polymer. Nonlinear constitutive equations also take part to represent the rheological behavior and fluid-rock iterations. A dimensionless numerical model is then developed by finite differences discretization. The solution is achieved in an implicit fashion for both pressure and concentration, but all coupled phenomena are evaluated explicitly. Validation for the model is performed by comparison with analytical solutions, established for simplified situations. This is done since there is no analytical solution for the problem at hand. A deep sensitivity analysis is performed under advection-dominant conditions. The analyzed variables are polymer concentration, injection rate, permeability, diffusion coefficient, inaccessible pore volume, adsorption, residual resistance factor and non-Newtonian viscosity. Additionally, a criterion for space-time discretization is developed aiming to minimize approximation errors. The proposed model has potential as a novelty in simple and low-cost laboratory experiment planning and data analysis.

Palavras-chave: Flow in Porous Media; Polymeric Solutions; Coupled Phenomena; Sensitivity Analysis; Finite Differences