非均匀载荷对高密射孔管抗挤强度的影响

EFFECTS OF NON-UNIFORM LOADS ON COLLAPSE STRENGTH OF HIGH-DENSITY PERFORATED CASING

在建立非均匀外载模型的基础上,对N80射孔管进行了研究。依建立的三维有限元模型及弹塑性理论为基础,借助有限元软件,对射孔管体抗非均匀载荷能力进行了数值模拟。并依其非均匀载荷下的大位移特征和强度特征,分别定义了临界载荷和等效抗挤强度。同时分析了不同模型在相同不均匀系数、同一模型在不同的不均匀系数的情况下对等效抗挤强度的影响。结果表明,射孔管抗非均匀载荷的强度远远低于抗均匀载荷的强度,其中不均匀系数起着关键作用。有利于指导在非均匀载荷作用下射孔管的抗挤强度的设计,对分析套管变形损坏的机理提供了依据,有利于对套管损坏预防提出有效的方案。

The N80 perforated casing is studied based on the establishment of the non-uniform load model. Firstly, the 3D FEM model is established. Secondly, the elasticity-plasticity theory and FEM software are adopted. Then the collapse strength of the perforated casing under non-uniform load is numerically simulated. The critical load and the equivalent collapse strength are defined respectively according to its long displacement features and strength features under non-uniform loads. And the variation of equivalent strength under different non-uniform coefficients and different models is analyzed to find out how the models and non-uniform coefficient affect the collapse strength. The research indicates the perforated casing has far lower collapse strength under non-uniform loads than under uniform loads, the non-uniform coefficient plays an important role. This study helps design the collapse strength of high-density perforated casing under non-uniform loads. It also provides theories for casing deformation and damage mechanism study, being helpful for the preparation of preventive measures for casing damage.