Abstract
The effect of the stability of a displacing front in gravity drainage on the displacement efficiency was discussed with dimensionless parameters. For gravity drainage in stable conditions, high displacement efficiency is achieved without the effect of gas fingering with the aid of a stable interface of displacement. When the displacement velocity is above the critical gravity drainage velocity, large fractions of water remain in the packed bed. Reflecting the nature of instability, the initial gas saturation varies widely from drainage to drainage. Heterogeneity in porosity enhances the effect of fingering and reduces the displacement efficiency. With an increase in Bond number and a decrease in capillary number, the initial gas saturation increases.
