Miscible displacement of a layer with finite width in porous media

Miscible displacement of a more viscous finite layer in porous media is simulated by means of high accuracy numerical schemes. Viscous fingers on the trailing front where the mobility ratio is unfavorable are found to catch up, however they never break through the stable leading front Two stages of fingering orientation are observed At an earlier time when the influences of finite thickness of the layer are not yet fully realized, the fingers move forward with the similar features to the conventional fingering findings. However, these fingering Patterns are redirected upstream after the arrival of most of fingers to the Leading front. The leading front remains stable with strong dispersion effects and moves nearly constantly with original displacing velocity. The growth rate of the layer thickness depends strongly on the viscosity ratio.