Linear Stability Analysis and CFD Simulation of Thermal Viscous Fingering Instability in Anisotropic Porous Media

Abstract

Water or steam injection in oil fields is a common method for enhanced oil recovery in petroleum engineering. The thermoviscous fingering instability is one of the main problems of a complex nature that decreases the efficiency of oil extraction. Actually, oil wells are a porous medium with a level of anisotropy for permeability and diffusion. In this paper, the thermal viscous fingering instability in anisotropic media is investigated using both linear stability analysis and computational fluid dynamics (CFD) simulation. For stability analysis, the growth rate of disturbances is determined by solving quasi-steady-state equations via a shooting method. The CFD simulation is performed by solving the governing equations of heat and mass transfer using a spectral method. It is shown that the longitudinal direction permeability and the transverse direction dispersion have important effects on the instability. The values of the thermal-lag coefficient and the Lewis number have opposite effects on the different types of displacements considered. When porous media are swept using cold fluid, increasing the Lewis number intensifies the level of flow instability.