摘要
采用小参数摄动法建立了非均匀载荷作用下具有初始椭圆度的磨损套管稳定性准则,根据计算得到的磨损套管相对应变及其临界值之间的关系确定磨损套管是否发生挤毁失效。分析了磨损套管相对应变及其临界值与套管外径、壁厚、磨损深度、载荷非均匀度、初始椭圆度之间的关系。套管外径增加导致失稳临界应变减少,磨损套管保持其稳定的壁厚也随之增加。非均匀载荷作用下磨损套管相对应变与初始椭圆度之间是线性关系,套管初始椭圆度越大,相对应变越大。相对应变与载荷非均匀性之间是抛物线关系。磨损套管载荷非均匀性越大,相对应变越大。非均匀载荷作用下磨损套管的相对应变随磨损深度线性增加。该准则能够用于评价非均匀载荷作用下含磨损缺陷套管的井筒的完整性。
The small parameter perturbation method was adopted to develop the stability criterion of a worn casing with initial ovality under non-uniform loadings, by comparing the relative strain of the worn casing against its critical value. The relationships between the relative strain and key parameters such as the outer diameter, the wall thickness, the initial ovality, the non-uniform loadings, and the worn depth of the casing were analyzed. The increase in the outer diameter of the casing decreased the critical value of the relative strain, and required a heavy casing to maintain its stability. The relative strain of the worn casing increased linearly with the initial ovality under non-uniform loadings. The relative strain was parabolically related to the non-uniformity of the loading. The bigger the non-uniformity coefficient, the greater the relative strain. The relative strain of the worn casing increased linearly with its worn depth under non-uniform loadings. The proposed stability criterion is expected to evaluate the integrity of wellbores which include worn casings subject to non-uniform loadings.
出处
《工程力学》
EI
CSCD
北大核心
2015年第7期249-256,共8页
Engineering Mechanics
基金
国家自然科学基金项目(51174162)
关键词
小参数摄动法
稳定性准则
套管
非均匀载荷
偏心磨损
small parameters perturbation method
stability criterion
casing
non-uniform loadings
eccentric wear
