大庆胶凝原油启动屈服应力研究

准确预测胶凝原油管道的启动压力，是实现热含蜡原油管道安全经济输送、避免“凝管”事故发生的关键问题。根据原油流变性研究中剪切率和屈服值的定义，提出了胶凝原油启动剪切率和启动屈服应力两个新概念。研究认为，对应热油管道最低临界启输流量，管道存在启动剪切率，对应启动剪切率的屈服应力定义为启动屈服应力。使用室内模型环道，对大庆胶凝原油的启动特性进行了实验研究。结果表明，原油析出的蜡晶对静态降温过程胶凝原油结构强度的作用远大于对动态降温过程生成结构强度的作用。原油静态降温幅度越大，新生长的结构越强。胶凝原油启动屈服应力的主要影响因素有启动温度、启动剪切率和静态降温幅度，它们之间的关系可用三元线性方程描述。

Investigation on start-up yield stress of Daqing gelled crude oil

The start-up shear rate and the start-up yield stress for the crude oil were put forward from the technical application angle, comparing with the shear rate and the yidd stress in the traditional rheology, Based on the minimum critical start-up flux for the hot oil pipeline, the start-up shear rate scope can be made certain, and the yidd stress according to the start-up shear rate was defined as the start-up yidd stress. The start-up process for Daqing gelled crude oil was experimentally studied, The results show that the contribution of new wax precipitation to the strength of the oll structure during static cooldown is larger than that during dynamic cooldown process. The larger the range of temperature declining is, the more the new grown structure works. The main factors in influencing the start-up yidd stress of the gelled crude oil should be the start-up temperature, the start-up shear rate and the range of declining temperature during pipeline shut-down. And the relationship among the factors can be described by a threeparameter linear model.