A novel class of large-hydrophobe tristyrylphenol (TSP) alkoxy sulfate surfactants for chemical enhanced oil recovery

• New large-hydrophobe tristyrylphenol alkoxy sulfate surfactants were synthesized.
• Ultra-low IFT and good aqueous stability were obtained for different oils.
• Excellent performance were achieved in both outcrop and reservoir corefloods.

In light of recent technical advancements in alkaline-surfactant-polymer (ASP) flooding, the demand for high performance EOR surfactants is rapidly increasing and calls for a diverse raw material base. We have synthesized and tested a novel class of large hydrophobes for anionic surfactants that satisfy this need. A petrochemical based hydrophobe tristyrylphenol (TSP) in its alkoxy sulfate form was systematically studied with four crude oils. TSP based surfactants have unique structural features that can be easily tailored into EOR surfactants. The TSP alkoxy sulfate surfactants with varying lengths of propoxy (PO) and ethoxy (EO) chains were tested in microemulsion phase behavior experiments in order to obtain ultra-low interfacial tension at optimum salinity. The efficacy of these ASP formulations was successfully demonstrated in both outcrop and reservoir corefloods using both surrogate and live oils with high oil recovery and low surfactant retention.