中文摘要：

某油井G105钻杆在使用过程中发生刺穿失效。通过宏观分析、化学成分分析、力学性能分析、金相分析、扫描电镜分析及腐蚀产物XRD分析的方法对该钻杆的刺穿原因进行分析。结果表明该钻杆的失效原因是钻杆内表面发生氧腐蚀形成腐蚀坑;钻杆加厚过渡区存在截面变化而产生应力集中,加之腐蚀坑底部的应力集中,在腐蚀坑底部萌生疲劳裂纹并贯穿壁厚,管内高压钻井液沿贯穿裂纹由内向外刺出而失效。

英文摘要：

The piercing failure occurred in the using ofoil well G 105 drill pipe. The piercing failure reason was researched by macro analysis, chemical composition analysis, mechanical property test, metallographic analysis, scanning electron microscope analysis （SEM）, X-ray diffraction （XRD） analysis of corrosion products. The results show that the reason for the failure of the drill pipe is that corrosion pits form in the inner surface of the drill pipe due to oxygen corrosion, and the stress concentration appears in the thicker transition zone of the drill pipe as a result of the section changing, as well as the stress concentration appears at the bottom of the corrosion pits, the corrosion fatigue cracks initiate at the bottom of the corrosion pits, which penetrate the wall thickness, and the high-pressure drilling fluid of the inner tube thrusts out from the inside to outside along the through cracks, which can cause failure.