分支井连接井段井壁破坏特性分析

目前，分支井井眼连接井段失效问题是分支井技术面临的新的挑战，因为这可能导致井眼报废而无法达到预期的目的，因此，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和破坏规律，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和破坏的影响，以及连接处破坏的程度及变化规律；同时总结出连接井段井眼最稳定时的最佳分支造斜方位是沿着最大水平主应力方向。

THE DESTRUCTION CHARACTERISTIC ANALYSIS OF THE MULTILATERAL JUNCTIONS BOREHOLE

Presently, the multilateral wells technology are faced with a new problem that the formation collapse at the junction section result in the borehole rejection not to achieve anticipated purpose. So, based on the mechanics characteristic of the multilateral junction borehole, this paper studied the rule of the stress distribution and the formation collapse in multi-junction which used the finite element method to simulate the influence of deflecting radius & direction on it, analysed the destruction rules and degree of the multi - junction, and summarized a very important rule that the optimum branch deflecting azimuth is the direction of the maximum formation horizontal stress in borehole stabilization.