柔性钻杆O形圈球面密封性能研究

Research on Sealing Performance of O-ring Spherical Surface of Flexible Drill Pipe

柔性钻杆已成为老井改造和增产提效的重要工具,为保障柔性钻杆球面密封的可靠性,对设计的一种O形圈球面密封结构开展数值模拟和试验研究。基于ANSYS有限元分析软件探究密封间隙、流体压力、转动角度以及有无挡环等因素对O形圈von Mises应力、接触应力、有效密封宽度等密封特性参数的影响。结果表明:流体压力与密封间隙存在耦合关系,流体压力越高要求密封间隙越小;往复转动会导致最大von Mises应力和最大接触应力升高,且随着密封间隙增大而影响加剧;挡环的安装可有效防止在密封间隙和流体压力较大时O形圈挤入缝隙。通过室内试验验证了O形圈球面密封结构的可靠性,为现场应用提供了理论依据和技术支撑。

Flexible drill pipe has become an important tool for old well reconstruction and production increase and efficiency improvement.In order to ensure the reliability of the spherical seal of flexible drill pipe,numerical simulation and experimental research were carried out on a designed O-ring spherical seal structure.Based on ANSYS finite element analysis software,the effects of sealing clearance,fluid pressure,rotation angle and whether there is a retaining ring on the sealing characteristic parameters such as von Mises stress,contact stress and effective sealing width of O-ring were investigated.The results show that there is a coupling relationship between fluid pressure and sealing clearance,and the higher the fluid pressure,the smaller the sealing clearance is required.Reciprocating rotation will lead to an increase in the maximum von Mises stress and maximum contact stress,and the impact will increase as the seal gap increases.The installation of the retaining ring can effectively prevent the O-ring from squeezing into the gap when the sealing gap and fluid pressure are high.The reliability of the O-ring spherical sealing structure is verified through indoor tests,which provides a theoretical basis and technical support for field applications.