Study On The Effect Mechanism Of Ca-Mt Particles On The Stability Of Produced Water From Alkali-surfactant-polymer Flooding

With the continuous popularization of ASP flooding technology,the yield of produced water from ASP flooding is also increasing.Because of the produced water from ASP flooding contains a large amount of residual polymer,alkali,surfactant and other chemical agents,the composition of the produced water is very complex and changeable.At the same time,as flows through the underground reservoir,the crude oil will carry some of clay particles from the formation.And the particles affects the stability of the ASP flooding produced water,the treatment of the ASP flooding produced water becomes more difficult,has bad effect.It reduces the equipment efficiency,makes the processing costs have risen sharply.So that the produced water which will reinject to the reservoir does not meet the reinjection standard.Therefore,in order to achieve efficiency treatment of the ASP flooding produced water,it is urgent to study the effect mechanism of clay particles on the stability of the ASP flooding produced water.In this paper,Ca-Mt particle was used for study.First,the simulated ASP flooding produced water was prepared in laboratory,to study the effect of Ca-Mt particles on the oilwater separation characteristics of produced water.Based on the influence of Ca-Mt particles on the interface properties of produced water,the mechanism of Ca-Mt particles on the stability of produced water was determined.In addition,the effects of Ca-Mt particles on the produced hydrodynamic parameters and liquid film strength were studied by bottle test method and single drop method,and the microscopic action mechanism was disgused.The results show that CaMt particles can increase the stability of produced water and make it difficult to separate oil and water.As the Ca-Mt particles with low concentration and negatively charged will adsorb on the oil-water interface,the electrostatic repulsion is increased and the interfacial tension is reduced.As a result,the interfacial tension and Zeta potential first decrease and then increase with the increase of the particle concentration,and the interfacial elastic modulus first increases and then decreases.Based on the kinetic stability model,the particles can reduce the decomposition rate of oil droplets of the produced water and increase the half-life of demulsification.Low concentration of Ca-Mt particles can adsorption at the interface between oil and water,forming a stable interface membrane,as well as adsorption to the surface of oil droplets formed a stable oil-mineral flocculation structure,make the oil is not easy to gather.Therefore,the drainage time and half-life of the ASP flooding produced water with the increase of Ca-Mt particle concentration increases then decreases,and cracking rate constant of oil droplets is increase with the decrease of the first.