中文摘要：

套管在地层中多处于非均匀载荷之下，而非均匀载荷对套损影响甚大，在开采过程中，套管所受的非均匀载荷随着开采的进行而改变，设计的套管强度可能无法满足要求。针对上述问题，以弹塑性力学和现场数据为基础，建立了套管一水泥环一地层有限元模型，研究在不同的非均匀载荷、壁厚、钢级下套管的应力分布、变形大小、剩余强度等，从而研究非均匀地层载荷下套损的防控措施。研究表明：套管的最大应力随非均匀程度的增加而增大，且最大应力在最小水平主应力方向；在非均匀载荷作用下套管发生了（0．4—1）mm的椭圆变形，削弱了套管的抗挤能力；采用N80钢级的套管在不同的非均匀载荷下，最小剩余强度为（-9．0—75）MPa，而采用P110钢级套管其最小剩余强度为（175—282）MPa，因此提高钢级能有效防控非均匀地层的套损。

英文摘要：

A finite element model of casing - cement - formation is established based on elastic - plastic mechanics theory and the data of oilfield, the casing stress distribution, deformation and residual intensity under the condition of different non - uniform load, wall thickness and steel grade are analyzed, and the measures of prevention and control under non - uniform load are studied. The resuhs show that the maximum stress of casing rises with the increase of degree of loading＇s non - uniform and it is in the minimum horizontal principal stress direction. Furthermore, it generates （0. 4 - 1 ） mm elliptical deformation in the non - uniform load, which weakens collapsing strength of casing. At last, there is （ - 9. 0 - 75 ） MPa minimum residual intensity of N80 casing in the non - uniform load, but minimum residual intensity of P110 casing is （ 175 - 282 ） MPa in the same condition. It is the most effective measure of prevention and control casing damage of the non - uniform load.