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在油气井测试过程中，为了保证测试安全，必须准确掌握油管的轴向力与变形情况。测试油管下部因受压会发生螺旋屈曲，并与套管接触产生摩擦力。屈曲后油管进一步变形时，油管轴向力与变形的关系非常复杂。常规计算方法没有考虑摩擦力对变形的影响，其结果不适用于高温高压井测试管柱安全分析。文章经过把塑性力学应力一应变关系与油管轴向力一变形关系进行对比，提出了用塑性力学增量理论的思想，来计算油管轴向力与变形的增量计算模型。通过现场应用，证明了这种计算方法的科学性和实用性。

Incremental Calculation Model of Testing String Deformation in a High-temperature and High-pressure Well

In the process of oil and gas well testing,it is imperative to know well the tubing deformation related to its axial force in order to ensure the safety in testing.Spiral buckle can be formed at the lower part of the tubing because of forcing,then the frictional force will be produced when the spiral buckle is in contact with the casing.While the tubing buckled is further deformed,the relation between the tubing axial force and its deformation is very complicated.The influence of the frictional force on the deformation wasn't considered in conventional calculation method,therefore its result calculated wasn't suitable for safety analysis of the testing string in a high-temperature and high-pressure well.In the paper,through contrasting plasticity stree-strain relation with tubing axial force-deformation relation,it is put forward that an incremental calculation model of computing tubing axial force and deformation may be set up on the basis of plasticity increment theory.The scientific property and practicality of such a calculation method were proved out by means of on-site application.