Study On The Relationship Between Isothermal Crystallization Microscopic Characteristic And Rheology Of Gelled Crude Oil

The rheology of gelled crude oil is determined by its internal diverse wax crystal structure.The rheology varies with the precipitated wax crystal content,structure and morphology.In this article,the gelled crude oil rheology paracmeters were gotten through rheometer experiments on the condition of small amplitude oscillatory shear and constant shear rate restart,while the isothermal crystallization microscopicparameters were gained by polarized microscope.Their change rule was analysed and the relation between gelled crude oil rheology and wax microscopic characteristics was studied qualitatively and quantitatively.The article discussed the effect of different processing conditions on gelled crude oil rheology and wax microscopic characteristics,explained the root cause of the network structure change of gelled crude oil and determined the exponential function relation between storage modulus and wax area during isothermal incubation period.Meantime,orthogonal experiment was applied to analyse the influence-degree of restart temperature,static cooling rate,static cooling amplitude and standing time on the storage modulus,yield stress and wax crystal parameters.The result stated that the influence of restart temperature was biggest,while the influence of other factors was relatively small.Then,the support vector regression method was made use of to forecast the storage modulus and yield stress with multiple wax crystal parameters in consideration of the complex situation.Fitting the regressive function,the relationship between gelled crude oil rheology and wax crystal characteristics was established through quantitative analysis.At last,according to the gray system theory,the impact of wax area,particle number,fractal dimension,roundness and dave on the gelled crude oil yield stress was discussed.It showed that precipitated wax content plays the most important role among all the wax parameters,and roundness was the weakest one.We hope the research can promote further study on the process of gelled crude oil isothermal crystallization.