一种新的胶凝原油管流启动屈服应力测算方法

A new calculation method of start-up yield stress for gelled crude oil pipe flow

准确预测胶凝原油的启动屈服应力,是实现含蜡原油管道安全经济输送、避免"凝管"事故发生的关键所在。以管流试验数据为基础,分析了管道轴向受压时间差异对胶凝原油启动屈服应力测量结果造成的影响。结果表明:在管流装置中,启动屈服应力的测量值随测量管段长度的增大呈减小的趋势。结合三参数双曲模式触变方程,提出了一种基于非线性最小二乘拟合原理的数据处理方法,能够求得测量管长趋于无限短时胶凝原油的启动屈服应力,统一了对特定工况下凝油结构强度的评价标准。

To accurately predict the start-up yield stress for gelled crude oil is the key to realize safe and economic transportation of waxy crude oil pipeline and avoid its condensation accident.Based on pipe flow test data,impact of pipeline axial compression time difference on the measured result of gelled crude oil start-up yield stress is analyzed.The results indicate that in the pipe flow device,the measured value of start-up yield stress decreases with the increase of the length of measured pipe section.Combined with three-parameter hyperbolic model thixotropic equation,a data-processing method based on nonlinear least squares fitting principle is proposed,which can calculate the start-up yield stress of gelled crude oil when the measured pipe tends to be unlimitedly short and unify evaluation standards of gelled oil structural strength under specific condition.