Research On Stability And Demulsificationand Dehydration Mechanism Of Heavy Oil Emulsion In Liaohe Oilfield

The demulsification of heavy oil emulsions is an important problem related to producing,transporting and refining heavey oil.Liaohe Oilfield is a typical heavy oil field,and its heavy oil has the characteristics of high viscosity,high density and high content of resin and asphaltene.In view of the current situation of high-stability W/O emulsions in the thermal recovery process of heavy oil in Liaohe Oilfield,the influence of natural emulsifier with asphaltene as the important role on its stability is studied from the microscopic point of view by means of scanning electron microscope(SEM)and infrared spectroscopy(IR),and a new type of high efficiency and environmental protection ionic liquid(ILs)was used to explore the demulsification mechanism and law of demulsification,which provided theoretical and experimental support for the field application of this technology.First,the viscosity-temperature curve,density-temperature curve characteristics and group component content of heavy oil were determined by laboratory experiments,and the asphaltene component was extracted from heavy oil for microscopic morphology and functional group analysis.The influence of liquid stability finally simulates the molecular structure of asphaltenes based on molecular weight measurement,infrared spectrum analysis and XRD test results.Secondly,the emulsion with 10%~60% water content was prepared.According to the results of polarization microscope image and particle size distribution analysis results,the emulsion type and droplet distribution were judged,and then the emulsifying ability of heavy oil was investigated by measuring the viscosity-temperature curve.On this basis,four kinds of imidazole ionic liquids were selected for demulsification experiment,and the optimal dehydration conditions were selected by changing the dehydration temperature,water content and ionic liquid concentration,and orthogonal experiments were designed according to the experimental results.The results show that the dehydration efficiency of [HMIM] TFO ionic liquid as demulsifier at 1500 ppm and 70 ? for 60 minutes can reach more than 90%,and at the same time,the change of droplet size distribution during dehydration is observed by polarizing microscope,which proves that ionic liquids have high efficiency demulsification performance.Finally,the samples before and after demulsification were analyzed by infrared spectroscopy,and the demulsification mechanism of ionic liquid was summarized.The research results of this paper can provide a certain basis and idea for the application of ionic liquid demulsification technology in petroleum industry,and lay a solid foundation for the realization of high efficiency and environmental protection demulsification of heavy oil-water emulsion.