In this paper, thermal-viscous fingering instability of miscible flow displacements in anisotropic porous media is studied .for the first time An exponential dependence of viscosity on temperature and concentration is represented by two parameters β_T and β_C, respectively. The effect of anisotropic properties of permeability tensor, Lewis number and thermal lag coefficient are investigated. Creation and propagation of these fingers are playing an important role in displacement of fluids and especially on oil transformation from discovered oil reservoirs in enhanced oil recovery process. In nonlinear simulation, a spectral method based on the Hartley transforms are used to model the thermal-viscous fingering instability in anisotropic porous media. The results include concentration and temperature contours, sweep efficiency, and mixing length. The results indicated that by increasing the anisotropic permeability ratio, the fingers arrive later to the end of the front, instability decrease and more stable flow is obtained. Also, by increasing the Lewis number, thermal front appears without any fingers. Decreasing the thermal lag coefficient causes to the thermal front stays behind the flow front and increasing the stability of the flow field.

Keywords: Thermao-viscous fingering, nonlinear simulation, thermal lag coefficient

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