φ139.7 mm×12.7 mm CB125HC 高抗挤套管 抗外挤性能研究

Study on External Collapse Resistance of φ139.7 mm×12.7 mm CB125HC High Anti-collapse Casing

利用实物试验和有限元模拟研究了几何参数对高抗挤套管抗挤性能的影响。检测10支同批次φ139.7 mm×12.7 mm CB125HC套管的外径、壁厚等几何参数,利用立式挤毁试验系统进行挤毁试验,得到套管抗挤强度值。对检测的几何参数和挤毁结果进行分析,研究壁厚不均度、椭圆度等对套管抗挤能力的影响。利用实测数据建立有限元模型,计算各个样品的抗挤强度值并与API计算值和实测值进行比较。结果表明:高抗挤套管的抗挤强度远大于API计算值,说明API公式不适用于高抗挤套管,有限元结果与试验结果相近,用有限元方法可快速预测高抗挤套管的抗挤能力。

Studied via the physical testing and the FE simulation is the effect of the geometrical parameters on the collapse resistance of the high anti-collapse casing.The geometric parameters like OD and WT of three pieces of the φ139.7 mm×12.7 mm CB125HC casings of the same batch are inspected.And the collapse test is also conducted with the vertical collapse testing system to the said casings,and thus the anti-collapse strength thereof are obtained.The geometric parameters resulted from the inspections and result from the collapse test are analyzed so as to investigate the effects by the wall thickness unevenness and the ovality on the collapse resistance of the casing.The FE model is set up with the data as actually measured to calculate the collapse strength values of each specimen which are then compared with relevant API calculation values and the measured values as well.As a result it is shown that the collapse resistance of the high anti-collapse casing is far higher than the API calculation value,which means that the API-specified formula is not applicable to the high anti-collapse casing,and that the FE result is close to the testing result.So it is concluded that the above mentioned FE method is capable of quickly predicting the collapse resistance of the high anti-collapse casing.