套管定向钻井锁定器设计与仿真分析

Design and simulation analysis of drill lock assembly for casing directional drilling

摘要:

套管定向钻井技术是一种新型定向钻井工艺方法，兼备套管钻井和定向钻井的优势，能够实现高效的定向钻井目标。锁定器作为套管定向钻井系统中的关键部件，其性能好坏将对钻井可靠性产生直接影响。本文设计了一种将锁定器活动机构部件全部密封的结构形式，对锁定器中的传扭和轴向限位进行承载力计算分析，采用两参数Mooney-Rivlin超弹性本构模型，对两端关键密封O形圈的装配间隙以及橡胶硬度的承受密封压力情况进行分析，研究表明，锁定器芯承受最大65011 N·m的制动扭矩时，单个传扭键承受10835 N·m的扭矩，应力为74.86 MPa，单个定位卡可承受184520 N的竖向承载力，应力为659 MPa，两者的应力均小于所使用材料的屈服强度930 MPa，锁定器的轴向承载能力和传扭性能均满足设计要求；配合间隙以及橡胶硬度均对O形圈密封性能产生影响，仿真结果表明，在所选公差配合范围内，O形圈表面接触压力均大于外界压力，能够实现有效密封，考虑到间隙越小，Mises应力和剪切应力也随之增大，过大的应力会使密封圈损坏，且不易装配，因此配合间隙选择大值；橡胶硬度越大O形圈的密封性能越好且在相同介质压力下O形圈的形变越小，通过数值模拟选择90 HA硬度的O形圈，可以满足锁定器的密封需求。

Abstract:

Casing directional drilling technology is a new type of directional drilling technology， which has the advantages of both casing drilling and directional drilling， and can achieve efficient directional drilling targets. As a key component in the casing directional drilling system， the performance of the locking device will have a direct impact on the drilling reliability. In this paper， a structural form is designed to seal all the parts of the moving mechanism of the lock， and the bearing capacity of the torque transfer and axial limit in the lock is calculated and analyzed. The two-parameter Mooney_Rivlin superelastic constitutive model is used to analyze the assembly clearance of the key seal O-rings at both ends and the sealing pressure of the rubber hardness. When the locking core is subjected to the maximum braking torque of 65011N·m， a single torsion key is subjected to the torque of 10835N·m with a stress of 74.86MPa， and a single positioning card can withstand the vertical bearing capacity of 184520N with a stress of 659MPa， both of which are less than the yield strength of the used material of 930MPa. The axial bearing capacity and torsional performance of the lock meet the design requirements. Mises stress and shear stress will increase when the gap is smaller. Excessive stress will damage the seal ring and make it difficult to assemble. The simulation results show that the contact pressure on the surface of the O-ring is greater than the external pressure within the selected tolerance range. Therefore， the fit gap is selected with large value； The greater the rubber hardness， the better the sealing performance of the O-ring and the smaller the deformation of the O-ring under the same medium pressure. By numerical simulation， the O-ring with 90HA hardness can meet the sealing requirements of the lock.