Experimental Investigation of ASP Flooding in Fractured Heavy Oil Five-spot Systems

Although alkaline-surfactant-polymer flooding is proved to be efficient for oil recovery from heavy oil reservoirs, the displacements mechanism/efficiency of this process in fractured systems needs to more discussion, especially in five-spot patterns. In this work, several ASP flooding test were performed on fractured micromodels which were initially saturated with heavy oil at constant flow rate and different fracture geometrical characteristics conditions. The ASP solutions are constituted from 5 polymers i.e. four synthetic polymers include three hydrolyzed polyacrylamide with different molecular weight as well as a non-hydrolyzed polyacrylamide and a biopolymer, 2 surfactants i.e. a cationic and an anionic surfactant and 3 alkaline types. The results showed that using synthetic and especially hydrolyzed polyacrylamide polymers with high molecular weight as well as the cationic surfactant increase ultimate oil recovery; however, type of alkaline does not play a significant rule. In addition, location of the injection well respect to fracture system plays a significant role in ASP flooding. For instance increasing angle of fractures with mean flow direction causes more oil recovery and delays breakthrough time. This work can be accounted as a comprehensive survey on ASP flooding which considers most of effective factors in this chemical EOR method.