Optimum phase type and optimum salinity profile in surfactant flooding

► The highest oil recovery in surfactant flooding may not correspond to the lowest IFT. ► The optimum microemulsion phase type is a function of many parameters such as relative permeability, in addition to IFT. It should be determined by core floods. ► The optimum salinity profile should include guard slugs before and after the surfactant slug, with the optimum salinity in these slugs. ► The conventional negative salinity may not be the best salinity profile.