从现役抽油机井油管上取材 ,依据油管螺纹尺寸特征制备相应的疲劳试件 ,模拟油管工况进行疲劳试验 ,对破断试样断口上的裂纹源区形貌及疲劳辉纹进行分析 ,计算出油管裂纹的扩展寿命。根据油管裂纹的扩展寿命占总寿命的比率 ,可以认为 ,油管的寿命主要取决于裂纹的萌生寿命。因此 ,在分析油管发生疲劳断裂的原因时 ,应主要针对裂纹的萌生原因进行分析 ,并就如何延长油管裂纹的萌生寿命提出相应的预防措施 According to the characteristics of tubing thread size, the corresponding fatigue specimens were prepared, the fatigue test was simulated under the condition of tubing, and the crack source pattern and the fatigue pattern on the fracture surface of the broken sample were analyzed. Tubing crack growth life. According to the ratio of the extended life of the pipe crack to the total life, it can be assumed that the life of the pipe depends mainly on the initiation life of the crack. Therefore, when analyzing the cause of fatigue fracture of tubing, the main cause of crack initiation should be analyzed and corresponding preventive measures should be put forward on how to prolong the crack initiation life