超稠原油的流变学特性及流动特征研究

Investigation on rheological properties and flow characteristics of heavy crude oils

该文针对三种不同类型的超稠原油的触变性、屈服应力和黏弹性等开展了研究工作。实验首先采用Haake RS6000旋转流变仪进行了流变学测试,结果表明随温度的上升,超稠原油的黏度、触变性和屈服应力均呈现出指数衰减的趋势;超稠原油表现出明显的黏弹性性质,且随频率的增大,样品从黏性主导转变成弹性主导。室内管道流动实验中,分别考虑温度、流速等因素研究了原油管道输运时的启动应力和流动规律,并将管流的测试结果与流变仪测量数据进行了对比分析,采用流变仪得到的在低剪切速率区间的流变学参数可以很好地应用于高剪切速率区的管道流动中。

In this paper, the thixotropy, yield stress and viscoelasticity of three different kinds of heavy crude oils were investigated. Haake RS6000 rheometer was used to measure the rheological characteristics. The results show that the values of viscosity, thixotropy and yield stress are kept in decreasing by exponent rule with increasing of the temperature. Heavy crude oil performs the obvious viscoelastic characteristic and will be changed from viscosity dominant to elastic dominant with the frequency increasing. By considering the influence factors of temperature and velocity, the law of start-up stress and the rule of flow were investigated in the experiments of pipeline transportation, respectively. A comparison between the pipe flow measurements and the rheological measurements indicated that the parameters of rheology under the low shear rates obtained by rheometer can apply successfully to the pipe-flow with the high shear rates.