Fundamental investigation of an environmentally-friendly surfactant agent for chemical enhanced oil recovery

Abstract Surfactant injection is an important chemical enhanced oil recovery (EOR) technique with beneficial impacts for oil recovery from subsurface reservoirs due to interfacial tension (IFT) reduction and wettability alteration. However, most of the available or proposed synthetic surfactants have negative environmental impacts. Here, a novel synthesis procedure of an amino-acid based (non-toxic; easily biodegradable) surfactant is described and its application for chemical EOR is rigorously tested using IFT, wettability and coreflooding experimental tests. The effect of salinity on the IFT reduction highlights the potential impact of injection water salt concentration on its performance. Two sets of carbonate and sandstone rock samples are used for wettability alteration tests. Two displacement tests quantitatively assess the performance of the proposed surfactant during injection as part of secondary and tertiary recovery schemes. The synthesized amino-acid based surfactant demonstrates good synergy with appropriate injection water salt concentrations. The wettability test results suggest that both sandstone and carbonate reservoir rocks would potentially benefit when subjected to chemical EOR using this surfactant. Comparisons between secondary and tertiary surfactant flooding schemes suggest that the surfactant is potentially more effective during secondary injection.