通过宏观检验、化学成分分析、金相检验和力学性能测试等方法,结合钻杆的受力和环境工况,对S135钻杆管体刺漏失效原因进行了分析。结果表明:刺漏失效是由于失效钻杆位于钻柱“中和点”区域,其外表面具有应力集中的腐蚀坑在交变应力和弯曲应力等共同作用下,在坑底萌生疲劳裂纹并扩展所致。

By means of macroscopic examination,chemical composition analysis,metallographic examination and mechanical properties testing,combined with the use condition and the applied load,the piercing reason of S135 drill pipe was analyzed. The results showed that the failured drill pipe was in the neutral point position of the string and bore the alternating stress and bending stress,which resulted in the fatigue crack initiation and expansion quickly in the bottom of the corrosion pits ,which with stress concentration in the outer surface of drill pipe.