Study On The Formulation And Microscopic Displacement Mechanism Of Self-emulsification

In our country, most oil fields have already been in medium-high water oil productionperiod at present. Although the tertiary oil recovery technologies have been applied, there wasstill considerable residual oil (above40%-50%) remained in the form of prism, dead end,island or film in the reservoir. It is an urgent task to develop new recovery techniques forimproving the oil recovery ratio of mature Oilfields.Anionic Gemini surfactant TADS-10was synthesized in this paper. The interfacialtensions between oil and the TADS-10/anionic surfactant petroleum sulfonate mixed system,the TADS-10/OP-10mixed system, the TADS-10/heavy alkylbenzene sulfonate mixedsystem or the TADS-10/4C12AC mixed system were tested through “rotating drop method”.The TADS-10/OP-10mixed system and the TADS-10/petroleum sulfonate mixed system canboth decrease the interfacial tension to ultralow(10-3mN/m). When TADS-10was mixed withpetroleum sulfonate, the interfacial tensions between oil and their SP or ASP mixed systemcan both reach to ultralow(10-3mN/m). When TADS-10was mixed with OP-10, petroleumsulfonate and heavy alkylbenzene sulfonate, the mixed systems all can make Daqing oilself-emulsified. Meanwhile the TADS-10/petroleum sulfonate mixed system can formMiniemulsion with oil, which grain size is0.5μm. The affection of TADS-10mixed systemson the elution ratio of oil sand was studied. The elution ratio of the TADS-10/petroleumsulfonate mixed system can reach to90.23%. The formulation of self-emulsification wasdeveloped by the study of the combination solution of TADS-10with traditional surfactant.The optimization prescription of formulation of self-emulsification was TADS-10/petroleumsulfonate mixed system, which mixed ratio was2:8.The physical model flooding experiment indicated that the self-emulsification floodingformulation can enhance the oil recovery efficiecy of oil to8.99%after water flooding. SPand ASP can enhance the oil recovery efficiecy of oil to18.25%and22.21%. Themicroscopic oil flooding experiment was analized the effection of self-emulsification onresdual oil. The study shows that the main microscopic mechanisms of flooding residual oilsobtained can reduce capillary pressure, oil was pulled by interfacial disturbance, and force outoil by emulsions, residual oil is emulsified into small droplets. They can flow throughporosity throat without capillary pressure, and big droplets are improved sweeping effect byplugging pore throat, and enhance the oil recovery efficiecy.