复杂地层钻具接头力学性能模拟及应用

在西部和南方海相复杂地层钻井中，不仅钻具失效严重制约了钻井效益，而且普通钻杆存在不足：不适合大钻压、高泵压和大扭矩钻井，呈现牺牲钻速保钻柱的现象；抗扭、抗拉强度较低，处理井下事故的富余能力小。因此，针对钻具螺纹的结构特点，提出了计算钻具螺纹力学特性的有限元力学理论和算法，并编制了国内唯一一套钻具螺纹力学性能有限元软件，可计算钻具螺纹接头在复合载荷下的力学性能。应用该软件为宝山钢铁公司开发了高强度、高密封的双台肩螺纹接头，投入生产并得到应用。

Simulation on Mechanical Properties of Drilling Tool Joint for Complex Formation Lithology and Application

For the complex formation in western China and part of the Southern China, the BHA failure is a very serious problem which has a big negative effect on the drilling cost.So conventional drill string is not suitable because it can not work under large WOB, high pump pressure and large torque,so the ROP is undesirable for protection the drill string from damage, and it is not able to deal with the problems as needed because of low torsional strength and tensile strength. The study of mechanical properties of tool joint is a base to study the BHA failures and design the new tool joint. According to the characteristics of axis symmetry of the tool joint,a FEA theory and algorithm suitable for the tool joint was put forward,that is the only software in China to compute the mechanical properties of the tool joint under combined load. Moreover,it has been used to develop a new-type tool joint suitable for complex formation in western China and southern China at Baoshan Steel Pipe Corporation.This fact indicates that the theoretical model and the results are reasonable.