Research On The Dynamic Wetting In Functional Surfactant Flooding

In recent years,oil extraction has entered the third stage and functional surfactants have been used in EOR.Gemini surfactant has unique advantages in oil displacement,but has not been perfected for dynamic wetting in oil displacement.In this paper,6 kinds of quaternary ammonium salt Gemini surfactants were used to conduct researches by experimental methods.Firstly,the type and concentration of surfactants with the best surface wetting reversal effect were screened by the contact angle method.They were:hydrophilic quartz tablets:0.01%G51,0.2%817;hydrophilic mica tablets:0.01%G51;oleophilic quartz tablet:0.05%G50,0.5%G53;lipophilic mica tablet:0.01%G50,0.2%G53.Secondly,the interfacial tension of different kinds and concentrations of surfactant solutions was determined by the rotary drop method and the influencing factors were analyzed.Surfactants A37,A42 and 817 can reduce the interfacial tension of the system to 10^-5 mN/m,10^-4 mN/m,10^-3 mN/m.By analyzing the wetting mechanism,a wetting model of the surfactant solution on the mica surface was established and verified based on experimental data.The correlation coefficient between the established wetting model and the experimental data is greater than 0.95,indicating that the model is suitable for characterizing the wetting process of the surfactant solution on the mica surface.The wettability factor K can be used to characterize the wetting behavior of the surfactant.The washing efficiency was calculated for different types and concentrations of Gemini surfactant solutions by oil-washing experiments,and the factors affecting the ability of the surfactant to wash oil were analyzed.Studies have shown that in addition to the conventional interfacial tension,dynamic wetting plays an important role in the oil-washing process,which provides new ideas for further investigation of surfactants for enhanced oil recovery.