| With the development of our country’s oil and gas,multi-phase mixed transportation of oil and water has become the mainstream transportation mode.During transportation,water-in-oil(W/O)crude oil emulsions were very easy to form due to external shearing.The viscosity and thixotropic properties of water-in-oil(W/O)crude oil emulsions were enhanced compared with those of waxy crude oil.In this paper,the degree of emulsification was changed by changing different stirring conditions,which was manifested as changing the particle number and surface area of droplets from the microscopic level,which played a role in occupying wax,colloid and asphaltene.The microscopic observation of water-in-oil(W/O)crude oil emulsion under different stirring conditions and the determination of rheological properties such as viscosity and thixotropy showed that the colloid involved in emulsification in crude oil itself,Asphaltenes had an effect on the viscosity and thixotropy of waxy crude oil emulsions.On the basis of microscopic observation,this paper proposed a viscosity prediction model related to the correction coefficient of water content D and the specific surface area ψ of emulsion.The maximum relative error between the predicted value and the measured value of the emulsion viscosity of the new model under different water contents was 7.79%,and the maximum error between the fitted value and the measured value was 10.57%,and the prediction effect was good.In addition,based on the existing thixotropy model of emulsion,combined with the microscopic observation results,a new thixotropy model of waxy crude oil emulsion was proposed.The proposed model could be applied in three aspects: the curve fitting of the emulsion,the prediction of the thixotropic curves of other water contents under the same stirring condition,and the prediction of the thixotropic fission curves of the same water contents and different stirring conditions.Experiments had verified that the average deviation of the prediction effect was within 15%,and the prediction effect was good. |
