通过宏观分析、尺寸测量以及材质分析, 对AT-16井钻杆NC50内螺纹接头胀大失效原因进行了详细的调查分析, 分析结果表明: 钻杆内螺纹接头胀大失效主要是在钻井过程中钻杆接头所承受的扭转载荷过大所致。有限元计算结果和双台肩接头钻杆在塔里木油田实际使用效果表明: 双台肩接头钻杆的抗扭性能要优于单台阶螺纹接头钻杆, 为有效地防止在深井和超深井钻井过程中钻杆内螺纹接头发生胀大失效, 建议采用双台肩接头钻杆。

Thorough investigation on swelling causes of drill pipe NC50 tool box joint which swelled at AT-16 well was done. And based on the analysis results it was considered that drill pipe tool box joints swelled due to over torque during drilling. It was proved that the anti-twisting property of drill pipe with double shoulder tool joints was better than that of single shoulder tool joints in accordance with finite element calculation results and the actual use effect in Tarim oil field. It was suggested that the dill pipe with double shoulder toll joint should be applied in order to prevent tool box joint from swelling in deep and ultra-deep well drilling.