An Experimental Investigation on Foam Injection in a Fractured Porous Media: Effect of Viscous Cross Flow

Cross flows and molecular diffusion are of high importance in recovery of bypassed oil. Thus, reinforcing viscous cross flow as a driving force in order to increase the oil recovery is proposed. In order to strengthen viscous cross flow, injection of a viscose fluid such as foam in fractured micromodels was applied. Based on the results, effective mechanisms of bypassed oil displacement were viscous cross flow and emulsion.

Two distinct region were observed in displacement front: a dynamic region in which the saturation of foam is low and participation of surfactant saturation is higher than gas phase.; and a static region that foam saturation is high and fluids’ mobility are lower than dynamic region. In dynamic region, some oil was recovered by emulsion. The oil droplets flew through arc-like aqueous phase and accumulated near the downstream. Pressure drop in the main stream is the driving force of moving these oil droplets through arc-like front. Hence, the driving force is constant and reinforces the fluids flow up to a certain level in dynamic region. Therefore, each pressure drop in the mainstream corresponds with particular foam invasion depth and is proportional to an individual recovery factor.