Preparation And Performance Evaluation Of Self-emulsifying Viscosity Reducing System For Heavy Oil

Because heavy oil has great viscosity and can not be stirred at low temperature,the idea of self-emulsifying viscosity reducing is put forward so that it can be emulsified by appropriate surfactant and a little of mechanical energy?such as slight shaking,stirring or ultrasonic?,which can reduce the viscosity of crude oil.In this paper,a new Gemini surfactant was synthesized in two steps using N,N'-dimethylethylenediamine,sodium 2-bromoethanesulphonate and 1-bromododecane,and the reaction conditions were optimized.In the first step,the optimum reaction temperature was 80?,the optimum reaction time was 48 hours,and the optimum molar ratio of N,N'-dimethylethylenediamine and sodium 2-bromoethanesulphonate was 1.3:2.In the second reaction,the optimum reaction temperature was 80?,the optimum reaction time was 48 hours,and the optimum molar ratio of intermediate product and 1-bromododecane was 1.1:2.The critical micelle concentration of target compounds is 3.125×10^-5mol/L,and the corresponding surface tension is 41mN/m.When the concentration of target product is 0.5%,the interfacial tension can be reduced to 0.0099mN/m.When the concentration of target product is 800mg/L,the adsorption capacity on the surface of quartz sand can reach1.78mg/g.Sodium carbonate was selected as alkaline initiator for the self-emulsifying viscosity reducing system for heavy oil.OP-10 and alkyl benzene sulfonate were selected to be combined with the synthesized Gemini surfactant.Orthogonal experiments were carried out under the condition of adding 0.5%sodium carbonate.The experimental results showed that the order of the three factors was Gemini surfactant concentration,OP-10 concentration and alkyl benzene sulfonate concentration.When the concentration of Gemini surfactant,OP-10 and heavy alkyl benzene sulfonate is 0.6%,0.4%and 0.4%respectively,the viscosity reduction effect of self-emulsifying viscosity reducing system is the best.The performance evaluation of the self-emulsifying viscosity reducing system showed that with the increase of oil and water ratio,the viscosity of the emulsion formed by self-emulsifying viscosity reducing system and heavy oil would increase;with the increase of temperature,the viscosity of the self-emulsifying viscosity reducing system and the emulsion formed by heavy oil would decrease;at the same time,the increase of temperature would cause the stability of the emulsion;the system has good ability of temperature and salt resistance,and the interfacial tension can be reduced to 10^-33 orders of magnitude at 50?.