Study On The Thixotropic Characteristics Of Daqing Gelled Crude Oil

The thixotropic properties of Daqing gelled crude oil which has certain heat history and shear history during its first breakdown are studied in this paper. The rate of the crude oil breakdown and its influencing factors such as the restart temperature, the static temperature drop and the restart shear rate are analyzed. A series of thixotropic models are examined based on the experiments to see their fitting effects. The results show that the hyperbolic model is more proper in fitting the experimental curves. The parameters in this model are further discussed. Through the multiple linear regression method, a functional expression describing the relation between the characteristic parameters in the hyperbolic model and the influential factors including the restart temperature, the static temperature drop and the restart shear rate is deduced; Futhermore, a computation method of crude oil thixotropy parameters using feed-forward BP network is put forward. The simulation results show that this method is of high accuracy and not dependent on function form. Besides, the peak point and the equilibrium point on the thixotropic curve are of special importance that the relaitons between these two points and the influential factors are set up respectively.