管输过程中加剂原油粘度变化的预测方法

以剪切作用对加剂原油粘度影响的数学模型和含蜡原油粘温关系机理模型为研究核心,建立了管输过程中加剂原油粘度变化的预测方法,大大减少了试验模拟的工作量和时间.通过对加剂大庆原油、加剂青海一厂原油、加剂青海混合原油和加剂中原原油44组管输模拟试验数据的检验,得出预测结果与模拟试验结果的平均相对偏差为11.5%.粘度预测值、测量值与按照降凝剂效果评价规范的"快速降温"方法评价结果对比表明,以管输应用为目的的降凝剂效果评价必须考虑剪切效应,该研究成果为快速预测管输条件下降凝剂的改性效果提供了一种有效手段.

Prediction of Viscosity for Waxy Crude Oils Beneficiated by Pour Point Depressants During Pipelining

The viscosities of waxy crudes beneficiated by pour point depressants (PPD) may vary after the pump shear or pipe flow shear. The only way for controlling these viscosity variations is to measure the viscosities by the simulation experiments before,which are quite time-consuming for long distant pipelines. A method for predicting the viscosity variations during pipelining is presented in this paper based on the model for predicting shear effect on the viscosity of PPD-beneficiated waxy crudes and the model for predicting nonviscosity of waxy crudes as a function of temperature and precipitated wax. The viscosities of four kinds of PPD-beneficiated waxy crudes during pipelining are predicted according to the presented prediction method. The predicted viscosities fit measured viscosities well with an absolute average deviation of 11.5% for all 44 data. The comparisons between the measured or predicted viscosities during pityelining and the viscosities obtained in the standard PPD evaluation experiment show that the PPD evaluation for the practical application should take shear effect into consideration. The achievements in this paper bring forward a way to evaluate quickly the PPD effect during pipelining.