Cationic Gemini Surfactant Flooding Mechanism

As the exploitation of oil field,extracting oil by water-flooding has become very difficult.Due to the low recovery efficiency of water-flooding,adopting chemical flooding to enhance crude oil recovery has become a main research direction in oilfield development.One type of chemical flooding methods,surfactant flooding,which is getting more and more attention,has a great application prospect in the EOR.This paper mainly studies the surf activity,ability to reduce oil/water interfacial tension and change solid surface wettability of cationic dim Eric surfactant,as well as its displacement efficiency.TEXAS-500 spinning Drop interfacial tensiometer is used to measure the interfacial tension of three kinds of cationic dimeric surfactants,12-4-12,15-4-15 and 12-4-12.Compare their ability to reduce oil/water interfacial tension,and study the effect of different factors(temperature,concentration,ph,sodium chloride and ploymer)on interfacial tension.It is concluded that when the concentration of 15-4-15 is 500 mg/L,the order of magnitude of interfacial tension reaches 10-5;when the concentration of 12-4-12 is 200mg/L,the order of magnitude reaches 10-4.The interfacial tension is ultralow when the concentration sodium chloride is 50mg/L;it is slower to reach ultralow interfacial tension when the concentration of ploymer is 1000mg/L,but it can maintain for long timeDSA100 contact angle meter is used to measure the contact angle of oil-wet surface and water-wet surface of cationic dimeric surfactants 12-4-12?15-4-15?20-4-20 and ordinary surfactant CTAB.It can be concluded that cationic dimeric surfactants is more effective in changing surface wettability of solid than DSA100.Cationic dimeric surfactant can change oil-wet surface into hydrophilic or strongly hydrophilic surface,and so that greatly improve the displacement efficiency.Displacement experiments of 12-4-12,15-4-15,20-4-20 and CTAB are conducted and CTAB is selected as comparison.The result shows that cationic dimeric surfactant is more effective in improving displacement efficiency and oil recovery than ordinary surfactant.On basis of performance analysis and displacement experiment on cationic dimeric surfactant,it can be concluded that cationic dimeric surfactant has better performance than ordinary ones.