针对尾管固井送入钻柱动态受力和变形开展了系统地研究，主要目的是评价送入钻柱的安全性问题。首先，根据送入钻柱的组合结构尺寸和井身结构尺寸，建立了钻柱承受摩阻力的力学模型，推导出了尾管固井过程中，由注入流体流动引起的钻柱摩阻力和变形计算的解析数学模型；其次，根据钻柱的组合结构尺寸、钻柱内多密度和变体积流体性质，推导出了尾管固井过程中多密度流体位置在钻柱内随注入时间变化的解析数学模型。模型已在四川龙岗Lg63井得到了应用，并验证了其可靠性和适用性。研究结果表明，在送入管柱内多密度流体作用下，建立的数学模型可以实时计算出避开送入钻柱发生交变载荷作用的排量参数，并能优化出送入尾管柱安全工作的最优工作参数，为尾管固井过程中钻柱动态摩阻力与变形引起的安全性评价提供了可靠的手段和方法。%This paper systematically studies the dynamic frictional drag and deformation of running drill string in liner cement-ing. The objective of the research is to evaluate the safety of the running drill string in liner cementing. At first,according to the structure size of drill string assembly and wellbore configuration size,the mechanical model of drill string under the fluid frictional drag was constructed,and the analytical mathematical model of the frictional drag and deformation of drill string caused by the flow of injected fluid in liner cementing was derived. And then,based on the structure size of drill string assem-bly and the fluid property of multi-densities and variable volume fluids in drill string,the analytical mathematical model of the depth of multi-densities fluid varying with the injecting time was deduced. Based on these mathematical models,the software, which evaluates the safety of the running drill string in liner cementing,was applied to well LG63 in Sichuan,and proved to be reliable and applicable. The research results indicate that under the action of the multi-densities fluid in the running drill string, the mathematical models and the software can find out the pumping fluid rate when the alternate load occurs in the running drill string,and optimize the parameters of safe operation of the running drill string. It provides a reliable means and approach for the safety evaluation of running drill string caused by the dynamic frictional drag and deformation string in liner cementing.
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