Optimum Formulation of Chemical Slug and Core Flooding Studies

Chemical-induced oil recovery has the potential to recover trapped oil, which is not possible to obtain by primary pressure difference and secondary water flooding methods. However, the implementation of chemical-enhanced oil recovery schemes requires a deeper understanding of the process for its successful implementation. The comprehension of mechanisms such as interfacial tension, emulsification, displacement efficiency, mobility ratio and wettability alteration can severely reduce the complexities involved in the system. Therefore, the roles of different mechanisms involved and their impacts on crude oil recovery, screening criteria for chemicals like alkali, surfactant, polymer or their combination depending on crude oil and heterogeneous reservoir properties are developed. Alkali–surfactant–polymer (ASP) flooding due to their synergistic effect offers a huge potential to recover residual oil. The understanding of the system or process is essential for the formulation of an optimum ASP slug that can maximize oil recovery. In this chapter, the overall screening criteria necessary for ASP flooding are formulated and discussed. The recovery of residual oil by ASP flooding in laboratories, pilot or commercial field scale in different parts of the world is summarized.