一种计算套管抗挤强度的新方法

利用高压水下应变测量技术,检测套管在挤毁过程中外壁的环向应变;运用弹塑性力学理论,建立模拟套管挤毁的有限元模型,通过计算也得到套管外壁的环向应变。将计算值与试验值进行对比,从而修正有限元模型,再利用修正后的模型进一步计算出套管的挤毁失效压力。该方法将有限元计算与应变检测结合起来,大大提高了有限元计算的精度,对预测套管的挤毁压力、指导高抗挤套管的开发具有一定的参考价值。

A new method for calculating the collapse strength of casing

By using the high pressure strain measurement technology,the loop strain on casing outer-wall is measured during the process of casing collapse.At the same time,based upon the elastic-plasticity theory,a FEA model is developed.The loop strain on the casing outer-wall is also calculated by this model.According to the measured strain,the FEA model is improved.Then the improved model is used to calculate the final casing collapse strength.This method combines FEA and strain test together and thus can get more accuracy results.The method can be taken as reference for calculating the collapse strength of high collapse strength casing.