基于动力松弛法的含铰柔性钻柱接触力学分析

Contact Mechanics Analysis of Flexible Drill String with Hinges Based on Dynamic Relaxation Method

柔性钻柱在钻进时伴随机构与结构的过渡,还与外管随机接触。采用有限元法将柔性钻柱和外管均处理为梁单元,铰离散为万向节单元,采用梁梁接触单元描述接触关系,建立外管内柔性钻柱有限元仿真模型,引入动力松弛法进行求解和分析,得到井眼造斜段柔性钻柱与外管之间接触力较大,柔性钻柱扭矩和轴向力随井深的增大而减小的结论。

During drilling operation,the flexible drill string is in random contact with the outer pipe along with the transition between the mechanism and the structure.Through having finite element method used to treat both the flexible drill string and the outer tube as 3-D beam elements,and the hinged connections of the flexible drill string discreted as universal joint connection elements,as well as having the beam-beam contact elements used to describe contact relationship between the flexible drill string and the outer tube,the finite element simulation model of flexible drill string in outer tube was established!,including having dynamic relaxation method introduced to obtain the results that,the contact force between the flexible drill string and the outer tube in deflection section of the wellbore is relatively large and the torque and axial force of the flexible drill string decrease with the increase of well depth.