易坍塌地层椭圆形井眼内套管应力的有限元分析  

Analysis on stress distribution of casing in sloughing formation with finite element method

作　　者：李军[1] 陈勉[1] 张广清[1] 张辉[1] 

机构地区：[1]石油大学石油天然气工程学院,北京102249

出　　处：《石油大学学报（自然科学版）》2004年第2期45-48,共4页Journal of the University of Petroleum,China(Edition of Natural Science)

基　　金：国家自然科学基金资助项目 ( 5 0 2 3 40 3 0 );中国石油天然气集团公司中青年创新基金资助项目 ( 0 3E70 19)

摘　　要：根据多孔弹性理论 ,对易坍塌地层井壁围岩的应力分布进行了分析 ,得出了易坍塌地层的井眼为椭圆形的结论。针对易坍塌地层的特点 ,用有限元方法分析了套管在椭圆形水泥环条件下的应力分布。数值计算结果表明 ,在保证固井质量的前提下 ,椭圆形水泥环有利于改善易坍塌地层套管的应力状态 ,应该在设计中予以考虑。但是 ,扩大井眼尺寸会影响到固井质量 。The pressure distribution of sidewall rock in the sloughing formations was analyzed on the poroelastic theory. It is concluded that the shape of wellbore in the sloughing formation is ellipse. The ellipse cement sheath (ECS) is advantageous to improve the casing stress of sloughing formation. The stress distribution of casing with the ECS in sloughing formation was analyzed with the finite element method. The result of numerical calculation shows that if the quality of cementing is good, the ECS should be taken into account in the well cement design. Because the enlargement of wellbore will affect the cementing quality, the ellipse degree of wellbore must be controlled in a reasonable range.

关 键 词：井眼 套管应力 有限元分析技术 易坍塌地层 井壁 多孔弹性理论 固井技术 

分 类 号：TE256.1[石油与天然气工程—油气井工程]