高温高压井测试油管轴向力的计算方法及其应用

针对高温高压井测试过程中油管受力及变形特点 ,在考虑油管螺旋屈曲段与套管之间摩擦力的情况下 ,提出了基于操作过程的计算测试油管轴向力的新方法。计算结果表明 ,摩擦力会改变油管轴向力的分布方式 ,使得轴向力分布与加载顺序有关。摩擦力大小和方向的改变 ,将使因高温高压产生的较大载荷无法向远处扩散 ,从而引起油管局部严重变形。该计算方法得到了室内模拟实验和常温常压井现场测试的验证 ,并成功地用于高温高压井的测试设计

A new method for testing tubing axial load in high-pressure and high-temperature wells

In the process of the highpressure and hightemperature (HPHT) well test, the axial load of the tested tubing is difficult to be calculated if helical buckling occurs in the tubing. That is because the helical buckling is accompanied by friction, and the friction value and direction often change when the loading and unloading take place repeatedly. A step by step model was established in consideration of the effect of friction. This model was used to calculate the tubing axial load according to the operation steps. Its result is more precise than that of the models, in which the friction was neglected. The calculation shows that the friction causes the tubing axial load distribution change significantly and is dependent upon the operation steps. The fiction can prevent large loads caused by high pressure and high temperature from spreading, which can result in severe deformation in a short part of tubing. The model was proved by both laboratory tests and data from oil fields. Its software was developed and used to test four HPHT wells successfully.