Flow Behavior of Foam: A Porous Micromodel Study

Abstract

Summary The flow behavior of foam in porous micromodels has been studied visually by use of etched silicon wafers. Air was injected into homogeneous and heterogeneous porous media previously filled with an aqueous surfactant solution. The flow characteristics and the mobility of the injected air were determined under different conditions of pore dimensions, air injection rates, and surfactant concentrations. In the experiments, air was found to be propagated by displacement of lamellae in long bubbles flowing and extending across several pore lengths, while the liquid flowed through the network of films. Propagation of foam bubbles formed at pore constrictions by snap-off was dominant in the heterogeneous model. Liquid and/or gas was trapped in some pores. The mechanisms observed depended on pore structure and surfactant concentration. A considerable reduction of effective air mobility was observed in the presence of foam. Mobility reduction depended on flow mechanisms.