分支井连接井段井眼力学特性的有限元分析

针对分支井分支处连接段井壁力学特性，首次研究了分支连接处的应力分布规律，应用有限元法模拟了造斜半径和造斜方位对连接段井壁应力分布分支处的造斜半径、分支井开窗方向和地层最大(小)水平主应力方向之间的夹角对分支连接处应力和岩石破坏的影响，建立了分支井连接井段的几何模型和有限元分析模型。重点研究了两个井眼之间的破坏深度和宽度与方位夹角和造斜半径之间的规律，得出在只考虑钻分支连接段-稳定段时分支最优钻进的方位是沿着最大水平主应力方向。这些研究结果已在钻井设计中得到应用。

FINITE ELEMENT ANALYSIS OF MECHANICAL FEATURES FOR CONNECTING SECTION OF BRANCH HOLE

Aiming at the mechanical features of the bore wall at the connecting section of the branch hole, the stress distribution law at the connecting section of the branch hole is studied first. With finite element method, the influence of the whipstocking radius and the angle between the opening direction of the branch hole and the direction of the maximum (or minimum) horizontal main stress of the formation on the stress and the rock damage at the connecting section of the branch hole is simulated. The geometrical model and the model of finite element analysis are set up for the connecting section of the branch hole. The relationship of the damage depth and width between the two holes, the angle and the whipstocking radius is investigated emphatically. It is found the optical drilling direction of the branch hole is along the direction of the maximum horizontal main stress when only considering the stability of the connecting section of the branch hole. The study results have been applied in the design of well drilling.