LAUSR

The success of foam displacement in porous media largely depends on its stability, which is adversely impacted by the presence of oil. In this study, we present the results of an experimental investigation into the effect of oil type and saturation on foam rheology in Berea sandstone using the nuclear magnetic resonance imaging technique. The results of foam quality scan in the presence of remaining hexadecane was compared with those from the oil-free case. We showed that the calculated apparent viscosity values in the presence of remaining hexadecane were higher than those in the absence of oil except at very high foam qualities. This was attributed to the dominance of relative permeability reduction and generation of oil-in-water emulsions over the foam-weakening effect of oil. A closer analysis of the fluid distribution further allowed us to quantify the relative significance of the identified oil displacement mechanisms, namely, the increased capillary number, and the micellar solubilization. Addition...