New method for rapid thixotropic measurement of waxy crude

Abstract

Waxy crude exhihibits a thixotropic behavior at the temperature closing to the gelation threshold. The thixotropic model is considered to be of crucial importance in the calculation of restart pressure for crude oil pipeline in shutdown. The thixotropic curves at several shear rates are necessary for the determination of the model parameters. The traditional measurement of thixotropic curves is complicated and takes much time, especially, it is impossible to be carried out under the condition of pipeline operation. According to the experimental observation and analysis, an empirical and simple method is developed to solve this problem. The test results show that the average relative error of the two methods is less than 25%.

Keywords

waxy crude / thixotropy / measurement / empirical method / stepped shear rate

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