某油井在下套管过程中发生了一起139.7 mm×7.72 mm J55长圆螺纹套管粘扣事故，为查清套管粘扣原因，结合油田套管下井上扣实际情况制定试验方案，采用全尺寸套管试样进行了上、卸扣试验。通过试验分析了各种上扣控制参量对套管粘扣性能的影响。依据试验结果推断，油田发生套管粘扣的原因既与使用操作有关，也与套管本身的质量有关。经过对油田下套管过程和实验室上、卸扣过程进行对比分析，指出了油田中在使用操作方面存在的问题。通过对套管粘扣形貌和规律进行分析，研究了套管本身的抗粘扣特性，发现了套管在螺纹加工质量方面存在的问题。

The galling accident of 139.7 mm ×7.72 mm J55 long round thread casing occurred during casing running down in one well. In order to find out the galling cause, the test procedure based on the casing well running down process in oil field was instituted, and the makeup and breakout tests with the full size casing samples were carried out. The effect of makeup parameter on galling was found out. It was deduced that the cause of casing galling accident in oil field was not only related to abnormal operation, but also related to casing quality according to the test results. The abnormal operation in oil field was pointed out by comparing makeup process in oil field with that in lab. The antigalling performance of casing was researched, and the problem of thread machining quality was found by analyzing galling morphology of the casing.