非均匀载荷作用下套管抗挤强度初探

API套管规范确定了套管在均匀流体静压载荷作用下的抗挤强度计算方法，非非均匀载荷对套管抗挤强度的影响几乎没有进行研究或作出规定，实际上，大多数油井套管的损坏是由非均匀载荷引起的。根据弹性力学理论，建立了套管在非均匀载荷作用下的力学模型，并应用逆解法对该力学模型进行求解，得到了在非均匀载荷作用下套管的抗挤强度计算式，研究表明，套管抗非均匀载荷的强度远远低于抗均匀载荷的强度，增强壁厚比提高钢级更为有效，该模型在理论研究上和现场应用中都有十分重要 的意义。

Discussion of Casing Collapsing Strength Under Non - uniform Loading

API casing bulletin gives the formulas and calculations of casing collapsing strength under uniform loading,but the effect of non-uniform loading on casing collapsing strength has been hardly researched.In fact,most of casings are collapsed by non-uniform loading.This paper has established the mechanical model of casing under non-uniform loading.Based on the elastic theory,the formula that can calculate casing collapsing strength under non-uniform loading has been obtained.Research shows that the casing collapsing strength under non-uniform loading is far less than that under uniform loading.As a result,it's more effective of increasing casing wall thickness than increasing casing steel grade.The model has great important significance both in theory research and in field application.