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

摘要： 基于 Hertz接触理论，建立了静态推靠式旋转导向（SRS）钻井工具的导向翼肋与井壁接触的理论分析模型，初步分析了接触应力的分布规律及其与各影响因素的关系；结合正交试验法分析了理论模型中各因素对最大接触应力的影响程度。结果显示，推靠力对最大接触应力影响最大，随推靠力的增大而近似呈线性增加；井壁弹性模量和翼肋曲率半径对其影响次之，随井壁弹性模量的增大而增大，随翼肋工作面曲率半径的增大而减小；井壁泊松比和翼肋厚度对其影响几乎可以忽略不计。现场使用 SRS钻井工具时，可以适当减小推靠力或者增大导向翼肋的曲率半径来降低导向翼肋陷入井壁的风险

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