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开采稠油更多地用水平井注蒸汽方式进行热采 ,而热采水平井套管的应力分析是一个复杂的三维力学问题 ,采用通用有限元程序进行分析的计算量大、机时长。为了有效地解决这个问题 ,针对水平井的几何和结构特点 ,先从普适的弹性力学方程出发 ,导出水平井套管在自然坐标系下的弹性力学方程。然后 ,利用摄动方法把三维问题转化为类轴对称问题 ,并采用环向有限单元的剖分方式 ,建立起相应的有限元方程 ,简化了问题的求解。同时 ,还揭示了热采水平井条件下剪切应力和轴向位移的变化规律 ,给出了水平井井口隆起等现象的合理解释
The exploitation of heavy oil is more thermal recovery by horizontal well steam injection, while the stress analysis of thermal well horizontal well casing is a complex three-dimensional mechanical problem. The calculation using general finite element program is large and the machine time is long. In order to solve this problem effectively, according to the geometrical and structural characteristics of horizontal well, the elastic mechanics equations of horizontal well casing in natural coordinate system are derived based on the universal elastic mechanics equations. Then, using the perturbation method, the three-dimensional problem is transformed into a quasi-axial symmetry problem. The finite element method is used to establish the corresponding finite element equations and simplify the solution of the problem. At the same time, the variation rules of shear stress and axial displacement under horizontal wells in thermal recovery are also revealed, and a reasonable explanation for the phenomenon of horizontal wellhead uplift is given