Taking into account the rotating effect of the drillstring, this paper presents a bifurcating differential equation for the rotating slender drillstring being in tension in vertical well section.

• 考虑到垂直井中钻柱受拉段在旋转时的转动效应，建立了顶部悬挂、受分布浮重作用的旋转细长钻柱的分岔微分方程。