In order to clarify the relations between the different initial states and safety of pipeline shutdown during the forward and reverse transportation process. Analyze the flow state and innovatively divide forward and reverse transportation process into 4 phase: forward cold oil control phase, forward hot oil control phase, reverse cold oil control phase, reverse hot oil control phase. Then, based on the analysis of the characteristics of pipeline temperature drop in different above phase, the safety of different initial state of pipeline shutdown is qualitatively analyzed from the view of oil temperature changes. Finally, define a new parameter “Safe Shutdown Probability $\varphi$" to describe and quantitatively analyze the safety of different initial phase of pipeline shutdown during forward and reverse transportation. The analysis results show that the shutdown safety is lowest when $\varphi =\pm 0$ and highest when $\varphi =\pm 1$.

为了阐明正向和反向运输过程中不同初始状态与管道关闭安全之间的关系。分析流动状态并将创新的正向和反向运输过程分为四个阶段：正向冷油控制阶段，正向热油控制阶段，反向冷油控制阶段，反向热油控制阶段。然后，在分析以上不同阶段的管道温度下降特征的基础上，从油温变化的角度定性分析了管道关闭不同初始状态的安全性。最后，定义一个新参数“安全关机概率$\varphi$描述和定量分析了正向和反向运输过程中管道关闭不同初始阶段的安全性。分析结果表明，当关闭时，关闭安全性最低 $\varphi =\pm 0$ 和最高的时候 $\varphi =\pm \mathrm{1个}$。