Study On The Influence Law Of Chemical Oil Displacement Agents On The Stability And Demulsification Effect Of Produced Water

With the industrial application of ASP flooding technology,oil recovery has been greatly improved.But at the same time,the production of ASP flooding produced water is also significantly increased.The composition of ASP flooding produced water is complex and the separation of oil and water is difficult,which has a negative impact on oilfield production and environmental protection.At present,the commonly used ASP flooding produced water treatment technology generally has the problems of poor economy and low efficiency.Therefore,it is urgent to innovate the treatment technology of produced water.Among them,the research on the influence law of produced water stability and demulsification effect under the action of chemical oil displacement agents is the premise for the innovation of its treatment technology,and has become an important task.In this paper,the simulated ASP flooding produced water was prepared by laboratory experiments.Firstly,the effects of chemical oil displacement agents concentration on the viscosity of produced water were studied.Then,the influence of chemical oil displacement agents concentration on the particle size of oil droplets and the interfacial tension of oil and water in produced water was studied by orthogonal test,and the Zeta potential of oil droplets under different concentration of oil displacement agents was measured.On this basis,bottle test method and single drop method were used to measure the stability dynamics parameters and interfacial film strength under the action of different oil displacement agents,and the stabilization mechanism of produced water under the action of chemical oil displacement agents was summarized.Finally,the demulsification effect of non-ionic demulsifier SN-1 on produced water containing different oil displacement agents was studied.The stability dynamics parameters and interfacial film strength of the produced water under different demulsifier concentrations were determined.The best combination of demulsification process parameters was optimized by orthogonal test,and the demulsification mechanism of the ASP flooding produced water was summarized.The experimental results show that the polymer concentration has the most significant effect on the viscosity of simulated produced water,and the viscosity of produced water increases with the increase of polymer concentration.The influence order of chemical oil displacement agents on the particle size of oil droplets is as follows: surfactant > polymer >alkali.The influence order of chemical oil displacement agents on the interfacial tension is as follows: surfactant > alkali > polymer.With the increase of alkali concentration,the absolute value of Zeta potential firstly increases and then decreases,the demulsification rate firstly decreases and then increases,and the interfacial film strength firstly increases and then weakens.With the increase of surfactant concentration,the absolute value of Zeta potential increases gradually,the demulsification rate decreases gradually,and the interfacial film strength increases gradually.With the increase of polymer concentration,the demulsification rate firstly increases and then decreases,and the interfacial film strength gradually increases.The addition of demulsifier can replace the surfactant on the interface,the dynamic stability of the produced water system is gradually weakened,and the interfacial film strength of O/W type droplets is significantly weakened.In the process of oil droplets approaching each other,the interfacial film drains liquid and becomes thinner,and the interaction force between the interfacial film decreases,which promotes the completion of the rupture and coalescence of the interfacial film.