A study on the permeability and flow behavior of surfactant foam in unconsolidated media

Foaming injected gas is a useful and promising technique for achieving mobility control in porous media. The foam flow is influenced by the foam ability, stability, bubble size and the grain size of the porous media. In this study, the effects of two surfactants, their concentrations, foam quality (gas content) and the additive on the foam ability and stability are evaluated. The results show that the better ability and stability of foam can be obtained through regulating the parameters mentioned above. The permeability test indicates that the foam possesses a lower flow rate than the surfactant solution. Not only that, the conductivity discrepancy among three sands is also reduced when foam is present. The primary mechanism for foam flow in different type of unconsolidated sand is Jamin effect which depends on the foam ability and stability. Experimental determination of the foam distribution and morphology in heterogeneous pores, via two-dimension sand plate by means of stereoscopic microscope is carried out to explain the effect of foam size-bubble size relationship on Jamin effect. The results show that when the bubbles are adequately stable, the flow behavior (transfiguration and fracture) of foam is determined by the relationship between the foam size and the pore size. The resistances arising from transfiguration and fracture lead to different foam conductivity in three sands. The more decrease of discrepancy between medium and fine sand is caused by the fact that transfiguration is able to generate more resistance than fracture.