油田套管在椭圆度影响下的应力分析

Stress Analysis of Oilfield Casing Influenced by Ellipticity

针对带有椭圆度的油田套管,参考以往油田套管研究的力学模型,利用ANSYS建立其有限元分析模型,研究其在内部均匀荷载和外部均匀荷载共同作用下椭圆度的存在对套管应力分布以及应力大小的影响。选取不同荷载组合进行对比研究,并与理想圆形套管数值分析结果进行对比。并对比研究不同套管壁厚下,椭圆度的存在对套管应力的影响。研究表明,套管应力大小以及应力分布与套管椭圆度值的大小有关。在内外部均匀荷载共同作用下,套管最大应力值随着椭圆度的增大而增大,最小应力值相反,应力分布不均匀度增加。带有椭圆度的套管随着套管壁厚的增加最大应力和最小应力值均减小,且最大应力和最小应力分别大于和小于同壁厚下理想圆形套管。

With a view to the casing with ellipticity,the finite element analysis model was established by using ANSYS with reference to the previous mechanical model of casing research. The study is aiming at the tube stress distribution and stress magnitude under the uniform load and external uniform load with the existence of ellipticity. The comparative study is done choosing different load combinations in the course,and the numerical results are compared with that of the ideal circular casing. And the ellipticity influence on the casing stress of different casing thickness is studied. The data shows that the casing stress and the stress distribution are related to the size of the casing ellipticity. Under the combined action of internal and external uniform load,the maximum stress value of casing increases with the increasing of ellipticity,the minimum stress value is opposite,and the stress distribution unevenness increases. The maximum stress and the minimum stress are reduced with the increasing of the casing thickness,and the maximum stress and the minimum stress are greater than and less than the ideal thickness of the casing respectively.