The Mechanism of Gas and Liquid Flow Through Porous Media in the Presence of Foam

Abstract

This study shows that in the presence of foam, gas and liquid flow separately through porous media representative of reservoir rock. These results were obtained by using ttacer techniques to measure the flow of the gas and liquid comprising the foam. Foam does not flow through the porous medium as a body even when the liquid and gas are combined outside the system and injected as foam. Instead, the liquid and gas forming the foam separate as the foam films break and then reform in the porous system. Liquid moves through the porous medium via the film network of the bubbles and gas moves progressively through the system by breaking and reforming bubbles throughout the length of the flow path. The flow rates of the gas and liquid are a function of the number and strength of the films in the porous medium. There is no free flow of gas,' i.e., no continuous gas phase. On the basis of these results, foam can be expected to improve a waterflood or gas drive by decreasing the permeability of the reservoir rock to a displacing liquid or gas. This improves the mobility ratio and thus the conformance of the flood.