In a stratified porous medium, foam can divert the flow from high permeability to low permeability layers. This interesting behavior found several practical applications in some reservoirs and aquifers. Moreover, experimental results have shown that foam blocking effect is maximum when the layers are isolated, i. e., when there is no capillary crossflow. Foam blocking in high permeability layers can be explained through the concept of limiting capillary pressure, , which is the maximum value of capillary pressure above which liquid films separating bubbles are broken.
In this study, we present a numerical simulation of foam displacement in a stratified system made of two noncommunicating layers with a permeability ratio of 5.4.
Numerical simulations are performed using a bubble-population correlation that allows us to compute explicitly foam texture in each layer from the physical properties of the rock (porosity, permeability and capillary pressure). We observe clearly the blocking effect of foam in high permeability layer, diverting gas to low permeability layer, due to capillary pressure difference.
Numerical results are qualitatively in good accordance with experimental data published in the literature.