The Formation and Characteristic of Middle Phase Microemulsion （I） Effect of Alcohols and Surfactant

Study of phase behavior in heptane/sodium dodecyl sulfonate（AS）/alcohal brine systems conatining highly purified surfacant is investigated using concentration scanning and interfacial tension methods.The effective regularities of the concentration of AS from 0.5% to 6%, the concentration of n-alcohol from 1% to 8% and the kind of n-alkanol form C₃ to C₆ on both the formation of the middle phase microemulsions and physics chemistry properties have been investigated. Some rules are worked out, which are belived to be of practical importance to tertiary oil recovery.