Abstract Shutdown of a waxy crude oil pipeline is unavoidable due to maintenance or emergency. It is critical to select the rheological models of gelled crude oil when investigating the pipeline restart process. Three crude oil rheological models are summarized based on previous researches in this paper, which are the viscoelastic model of a viscous type (Model 1), viscoelastic model of an elastic type (Model 2), and pure viscous thixotropic model without yield stress (Model 3). The same rheological data was fitted by the three models respectively. The critical state that pipeline can restart successfully is dominated by the slow creep of the gelled crude oil that can be regarded as an incompressible pipe flow, and this is verified by the pipe restart experiments under constant pressure conditions in this paper. To discuss the effects of the rheological models on calculation of pipeline restart separately, a simplified one-dimensional mathematical model with the pump boundary condition is established. The different calculated flow rate indicates that rheological models affect the judgement of the pipeline restart even though they are fitted from the same rheological data.

中文翻译：

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使用不同凝胶原油流变模型预测管道重启

摘要 含蜡原油管道因维修或紧急情况停运是不可避免的。在研究管道重启过程时，选择胶凝原油的流变模型至关重要。本文在前人研究的基础上，总结出三种原油流变模型，即粘性型粘弹性模型（模型 1）、弹性型粘弹性模型（模型 2）和无屈服应力的纯粘性触变模型（模型3）。三个模型分别拟合了相同的流变数据。管道能够成功重启的临界状态主要是凝胶原油的缓慢蠕变，可视为不可压缩的管流，本文通过恒压条件下的管道重启实验验证了这一点。为分别讨论流变模型对管道重启计算的影响，建立了带泵边界条件的简化一维数学模型。不同的计算流量表明流变模型影响管道重启的判断，即使它们是根据相同的流变数据拟合的。