Liu Hai-Fei, Xu Yuan-Yuan, Chen Hu, Zhang Jian, Xu Jing-Yu
State Key Laboratory of Technologies in Space Cryogenic Propellants, Beijing 100028, China.
Beijing Institute of Space Launch Technology, Beijing 100076, China.
ACS Omega. 2022 Aug 25;7(35):30816-30822. doi: 10.1021/acsomega.2c02234. eCollection 2022 Sep 6.
Heavy crude oil exhibits very complex viscoelastic behaviors due to its complex composition of resins, asphaltenes, saturates, and aromatics. It has a great influence on oil production and transportation. In this work, the viscoelastic behaviors of three different heavy crude oils were measured using a rotational rheometer. In conclusion, all of these heavy crude oils display linear viscoelastic behaviors in the experimental range. The loss modulus (″) of the three crude oils decreased as the experimental temperature increased, and the variation trends of the three crude oils were basically the same. However, the experimental temperature has almost no effect on the storage modulus ('), which always retained a constant value of 0.4 Pa. Furthermore, the storage modulus () and loss modulus (″) increase as the angular frequency increases. To describe the physical deformation characteristics of viscoelastic materials, the generalized Maxwell model and the fractional derivative Maxwell model are used to establish the constitutive relation of heavy crude oil. In conclusion, the generalized Maxwell model and the fractional derivative Maxwell model can predict the experimental results very well. All of the square of the correlation coefficient ( ) values are greater than 0.95. However, the number of fitting parameters for the fractional derivative Maxwell model is less than that for the fourth-order generalized Maxwell model which can save the calculating time. Therefore, the fractional derivative Maxwell model is suggested to describe the viscoelastic behavior of heavy crude oil in industrial applications.
由于重质原油中树脂、沥青质、饱和烃和芳烃的组成复杂，其表现出非常复杂的粘弹性行为。这对石油生产和运输有很大影响。在这项工作中，使用旋转流变仪测量了三种不同重质原油的粘弹性行为。总之，所有这些重质原油在实验范围内均表现出线性粘弹性行为。三种原油的损耗模量（″）随实验温度升高而降低，且三种原油的变化趋势基本相同。然而，实验温度对储能模量（'）几乎没有影响，其始终保持0.4 Pa的恒定值。此外，储能模量（）和损耗模量（″）随角频率增加而增大。为描述粘弹性材料的物理变形特性，采用广义麦克斯韦模型和分数阶导数麦克斯韦模型建立重质原油的本构关系。总之，广义麦克斯韦模型和分数阶导数麦克斯韦模型能很好地预测实验结果。所有相关系数（）值的平方均大于0.95。然而，分数阶导数麦克斯韦模型的拟合参数数量少于四阶广义麦克斯韦模型，这可以节省计算时间。因此，建议在工业应用中使用分数阶导数麦克斯韦模型来描述重质原油的粘弹性行为。
