连续管疲劳试验装置研制和实物试验研究

Development of Fatigue Life Test Equipment and Full-size Test for Coiled Tubing

为了能比较真实地模拟连续管在实际作业工况条件下,即在弯曲和内压联合作用下的疲劳寿命,研制出了一套专门用来进行连续管低周疲劳寿命的实物试验装备。该装置可以在0￣70MPa的内压条件下测试直径范围为12.7￣88.9mm的连续管的疲劳寿命。通过对直径和壁厚为38.1mm×3.2mm的CT-80连续管进行初步实物试验,获得了连续管疲劳寿命(循环次数)与内压的关系曲线、连续管循环次数与胀径关系的曲线、连续管循环次数与椭圆度的关系曲线以及连续管循环次数与壁厚的关系曲线。实物试验结果与国际先进的软件预测结果一致。

A full-size fatigue life test equipmeut for coiled tubing is developed to simulate the conditions of coiled tubing operation in fields. The equipment can be used to evaluate fatigue life for 12.7- 88.9 mm diameter coiled tubing under simulated 0-70 MPa internal pressure in the coiled tubing and combined bending load conditions. By testing the fatigue properties of 38.1mm diameter and 3.2 mm wall thickness CT-80 （tensile strength 552 MPa） coiled tubing, the fitting curve of fatigue life vs internal pressure, the fitting curve of diameter swell or danage vs cycle number, the fitting curve of CT ellipticity vs cycle number, and the fitting curve of wall thickness vs cycle number are obtained. It is shown that the fatigue test results obtained from the equipment agree very well with results predicted by Cerberus of CTES.