在油田生产过程中,弯曲效应是对井下管柱变形影响最为严重的因素之一。对管柱弯曲效应的研究对钻井和完井工艺的设计起到非常重要的作用。从国内目前的一些研究中可以发现,大多数的研究都忽略摩擦力的存在,实际上摩擦力的存在对弯曲效应的影响有着至关重要的作用。本文将研究摩擦力对管柱弯曲变形的影响,引入轴向力和扭矩,通过平衡方程和能量法建立了一个综合的力学模型;此外,本文建立了弯曲极限判别式,通过它计算出弯曲的临界载荷值,将其与抗扭强度进行比较,由此可准确的判断井下管柱的状态,指导现场的施工作业。 In the oilfield production process, the bending effect is one of the most serious factors that affect the deformation of the downhole tubular string. The study of the bending effect of the pipe string plays a very important role in the design of drilling and completion technology. According to the current research in China, most studies ignore the existence of friction. In fact, the existence of friction has a crucial effect on the bending effect. In this paper, we will study the influence of friction on the bending deformation of tubular string, introduce axial force and torque, and establish a comprehensive mechanical model by the balance equation and energy method. In addition, we establish the bending limit discriminant, Critical load value, compared with the torsional strength, which can accurately determine the status of underground pipe string to guide the construction site operations.