Optimization And Compounding Of Demulsifier Of Jianghan Oilfield Produced Fluid For The Third Time

Emulsion-breaking and oil-removing of the Jianghan oilfield produced fluid for the third time was the main purpose of this article.The experiment method of flocculation after demulsification was used in this paper.The first some demulsifier was dosed in the oilfield produced fluid for the third time,the second some flocculant was dosed in the water of dehydration so as to reduce the turbidity and oil content of the effluent.Finally,the water was filtered by the quartz sand.The demulsification process of the simulated emulsion was monitored by measuring a number of indicators of the demulsification process.The influences on the emulsion preparation such as temperature,oil-water ratio,stirring speed,stirring time and other factors was explored in this paper.When the preparation conditions were as follows,the properties of the emulsions obtained were similar to the Jianghan oilfield produced fluid for the third time:water: kerosene: crude oil =12:3:4(volume ratio),the preparation temperature is 30 degree,stirring time is 70 min,water phase pH between 6~7,stirring speed of 3000r/min.The demulsification effect of 13 kinds of demulsifying agents(SP1190?SP169?AP221?L31?L45?L65?AE9901?AE8031?AE2030?PRC01?PRC02?PRC04?PRC06)on simulated emulsion were explored.The test results were as follows: single demulsification agent AE9901 had the best performance in all demulsification agents,and when the dosage is 0.1g/L,the breaking time was 60 min,the temperature was 40 degree,then the demulsification dehydration rate was as high as 99.7%,but the turbidity of the water was 161.75 NTU,oil content of the water was 196.7mg/L,the two index was far beyond the scope of the follow-up water treatment technique.In this paper,according to the molecular characteristics of emulsifier and its demulsification effect the appropriate single agents were selected to mix,and the optimal volume ratio,dosage,demulsification temperature,demulsification time were explored.The experimental results were as follows: the best compound demulsifier was PRC06 and AP221 mixed by volume ratio 2:1,the demulsification temperature was 40 ~50 degree,the demulsification time was 50min~60min,the dosage was 0.1g/L.Then the best demulsification effect was got,the dehydration rate was 99.7%,the turbidity of dehydrated water was 4NTU,oil content was 40.5mg/L,the quality of dehydrated water was better than the water coming from the effect of single agent.The compound demulsifier had good adaptability for the water ratio of emulsion changing from 69.6% to 58.8%.The parameters obtained from the simulation experiment were applied to the Jianghan oilfield produced fluid for the third time directly.The results showed that the oil removal efficiency was good,the dehydration rate was 99.7%,the turbidity of water was 5.6NTU,and the oil content of the water was 47.2mg/L.The flocculation conditions of water removal were as follows:The optimum dosage of cationic polyacrylamide and ferric chloride was 1mg/L,90mg/L,and the settling time was 30 min.The removal of turbidity removal rate reached 75% by flocculation,the residual turbidity was 3.1NTU,the oil content of the dehydrated water removal rate reached 79%,the residual oil content was 8.4mg/L,the removal rate of suspended substance(SS)reached 87.5%,the remaining suspended solids content was 15mg/L.The oil content of the effluent which was filtered through the quartz sand was 1.1mg/L,and the content of SS was 0.6mg/L.Each index of the demulsification process was analyzed by the method of comparison.The experimental results showed that:The intensity of interfacial film was reduced by demulsifier molecules by adsorption and spread out in the form of oil-water interfacial film.Emulsion droplets impact due to random movement,which made the interface membrane broken,water began to assemble.In order to enhance the speed of the demulsifier molecular adsorption,the viscosity of the emulsion should be small,so appropriate temperature of demulsification was important.The interface membrane which was formed by different types of demulsifier molecules of compounded demulsifier was more loose than the interface membrane which was formed by single demulsifier,so the intensity of interfacial film was reduced.