无隔水管泥浆回收钻井系统吸入模块密封胶芯非线性摩擦接触分析

Nonlinear Frictional Contact Analysis of Seal Rubber in Suction Module of Riserless Mud Recovery Drilling System

建立无隔水管泥浆回收钻井系统密封胶芯及钻具二维轴对称有限元模型,使用非线性有限元方法计算密封胶芯与钻具间的接触压力大小,验证密封胶芯在无隔水管泥浆回收钻井中的可行性。研究摩擦因数变化对接触压力的影响,分析密封胶芯Mises应力峰值和钻具与胶芯间的摩擦力分布规律。结果表明:摩擦因数与胶芯密封面和钻具间的接触压力成非线性关系,胶芯主密封段接触压力随摩擦因数增大而减小,而胶芯锥形密封段和凸鼻形密封段的接触压力随摩擦因数增大而增大;胶芯Mises应力随摩擦因数增大而变大,且胶芯与钻杆接头上端接触时Mises应力峰值最大,容易导致胶芯破坏;胶芯与钻具间的接触面积基本不随摩擦因数变化而变化,摩擦力随摩擦因数的增大近似成线性增加;胶芯与钻杆接头接触时,摩擦力较大且增长显著,说明胶芯与接头接触时更容易发生磨损。

Two-dimensional axisymmetric finite element model of seal rubber and pipe were created for riserless mud drilling system.Based on nonlinear finite element analysis method,the contact pressure between seal rubber and pipe was calculated and the feasibility of seal rubber applied in riserless mud recovery drilling system was verified.The influence of friction coefficient on the contact pressure was researched while the distribution rules of friction between seal rubber and pipe and Mises stress peaks of seal rubber were analyzed.The results show that friction coefficient is in a nonlinear relationship with the contact pressure between the rubber sealing surface and the pipe,and the contact pressure in the seal rubber’s main sealing section decreases with friction coefficient increasing,while the contact pressure in seal rubber’s cone-shaped sealing section and the convex-noseed sealing section increases with friction coefficient increasing.Seal rubber’s Mises stress increases with the friction coefficient increasing,and Mises stress gets it highest peak when the seal rubber comes into contact with the upper end of drill pipe joint,and the seal rubber is easily impaired.The contact area between the seal rubber and the drilling tool almost does not change with the change of friction coefficient,and the friction force approximately linearly increases with the increase of friction coefficient.The friction force becomes large and increases significantly when the seal rubber comes into contact with the pipe joint,indicating the seal rubber is easily impaired while contacted with connector.