Study On The Stability And Demulsification Mechanism Of Chemical Flooding Produced Liquid

The study on the stability of chemical flooding and the mechanism of demulsification is the focus and difficulty of current research.This project mainly focuses on the simple noctane/water emulsions,the stability and instability process were studied,also the complex chemical flooding production fluid system,and its stability,demulsification mechanism and analysis of influencing factors.Bottle test,particle size analysis and TURBISCAN Lab? Master type stability analyzers and test methods for microscopic interface film properties were used to this simple noctane/water emulsion systems.The experimental results show that for the n-octane/TX-100/water emulsion,one of the factors affecting the stability of the system is the space steric effect produced by the TX-100 molecule,and the other is the effect of the droplet size on the floating speed.For n-octane/SDS/water emulsions,the electrostatic repulsion mainly hinders the collision between oil droplets,and the system has a higher modulus at the interface and a stronger Marangoni effect,which plays a significant role in the stability of the emulsion.A binary complex flooding simulated crude oil emulsion was prepared in the laboratory.Then the particle size,oil-water interfacial tension,and the stability and instability of the simulated emulsion were determined by varying the concentration of the oil displacement agent.The results show that the polymer reduces the particle size of the droplets,which results in the drop of water droplets and reduces the speed of liquid film drainage.The surfactant can reduce the oil-water interfacial tension and enhance the stability of the binary flooding fluid.In accordance with the evaluation criteria,the effective high-performance demulsifier BS-01,BSA-705,AR901,and AE401 were screened for Shengli Oilfield's Gusanlian analog chemical flooding production fluid,and their demulsification efficiency were better than those demulsifier using in the field.The demulsification conditions are preferably a demulsification temperature of 70°C and a concentration of 150 ppm.Secondly,the effects of interface active substances on the dynamic interface properties of crude oil and the effects of different demulsifiers on the dynamic interfacial tension of oil and water and the dynamic interfacial expansion modulus of oil and water were studied experimentally.The stability analysis was used to study the demulsification process and comprehensively analyze the mechanism of demulsification.The results showed that the active substances in crude oil caused some inhibition of surfactant adsorption on the interface,but the intensity of the interfacial film is quite high once the both of the above formed it.The relationship between the interface modulus and emulsion stability is quite strong.The smaller the interfacial modulus,the worse the stability of the crude oil emulsion and the larger the TSI value behaves.The addition of demulsifiers can significantly reduce the interfacial expansion modulus and affect the rate of droplet coalescence.Since the demulsifier molecules have a competitive adsorption relationship with the oildisplacement-removing molecules,the demulsifier should be of a type that has strong activity,low interfacial film strength,and difficult interaction with the original surfactant molecules.