关键词: 静态推靠式, 导向翼肋, 软地层, 赫兹理论, 最大接触应力, 正交实验法

Abstract: A theoretical analysis model of the contact between the steerable ribs of a static push-the-bit rotary steerable（SRS）drilling tool and sidewall was established on the basis of Hertz contact theory，and the distribution regularity of contact stress，as well as its relationship with different impacting factors were analyzed preliminarily. With the help of orthogonal test method，the impact of different factors in the model on the maximum contact stress was analyzed. Analysis results show that pushing force has the largest impact on the maximum contact stress，which increases almost linearly with the increase in pushing force；the impact of sidewall elastic modulus and rib curvature radius come the second，which increases with the increase in sidewall elastic modulus，and decreases with the increase in rib curvature radius；and the impact of sidewall Poisson's ratio and rib thickness are almost negligible. When SRS drilling tools are used in the field，the pushing force can be reduced properly or the curvature radius of steerable ribs can be increased properly to mitigate the risk of steerable ribs getting trapped in sidewall.

Key words: static push-the-bit, steerable ribs, soft formation, Hertz theory, maximum contact stress, orthogonal test method