EOR of Spontaneous Imbibition by Surfactant Solution for Tight Oil Reservoirs

Abstract

Spontaneous imbibition has been well investigated due to its impacts on oil recovery in conventional and fractured reservoirs. Differentiated in relation to the conventional reservoir, the tight reservoir is characterized by its ultra-low porosity and permeability. The scope of current research is to study the mechanism of imbibition under conditions of tight cores and surfactant solution. A series of experiments was conducted to determine the effects of tight core imbibition including three kinds of common surfactant solutions. The main factors of low IFT (interfacial tension) and wettability alteration are examined. The experimental results indicate that the original wettability affects the imbibition oil recovery, since low IFT and wettability alteration constitute beneficial parameters for imbibition as it concerns adhesive work reduction. The parameter of NBm-1 was not applied for optimal IFT or CA (contact angle) calculation concerning porous media with reduced capillary scale. Future research concerning the imbibition mechanism should take the property of surfactant into account.