Evaluation of Thixotropic Models for Waxy Crudes Based on Stepwise Shearing Measurements

Abstract

The thixotropic property of waxy crude is of great importance for oil pipeline restart. In previous studies, several mathematic models have been published for describing the thixotropic behaviors. However, no comparison of the prediction accuracy among these models has been carried out. In this work, thixotropic behaviors of four waxy crudes were studied experimentally using stepwise shearing measurements. The stepwise shearing method is proved to be a convenient method to obtain thixotropic experimental data. Seven published thixotropic models were evaluated based on these experimental data. A model with two structure parameters (Zhao's model) provides the calculation results mostly close to the experimental data.

Keywords:

• comparison
• mathematic model
• rheology
• thixotropy
• waxy crude