An instantaneous change of displacement during the cementing pump closing in the process of cementing in formations with a narrow density window may cause flow and pressure fluctuations and affect the wellbore safety and annulus pressure stability. Therefore, it is important to study the wellbore fluid flow characteristics in the process of cementing pump closing. In this paper, the authors have established control equations for the wellbore fluid flow in the process of instantaneous cementing pump closing and have determined the solution method and boundary conditions for the derived equations. The corresponding calculation software has been developed, and the fluid flow characteristics in the process of the cementing pump closing have been analyzed based on the practical calculation. This research may have important practical significance for optimizing the closing operation parameters in the process of cementing.

中文翻译：

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固井闭泵过程中流体流动特性的研究

在密度窗较窄的地层固井过程中，固井泵关闭过程中的瞬时排量变化会引起流量和压力波动，影响井筒安全和环空压力稳定性。因此，研究固井泵关井过程中的井筒流体流动特性具有重要意义。在本文中，作者建立了固井瞬时关闭过程中井筒流体流动的控制方程，并确定了推导方程的求解方法和边界条件。开发了相应的计算软件，并在实际计算的基础上分析了固井泵关井过程中的流体流动特性。