In ordinary stripping operations, the pipe falls into the wellbore under its own weight, and no additional downwardforce or pushing is required.
在平常的不压井起下钻作业中，管柱下入井眼是依靠其自身重量，不需要附加的向下载荷或者推力。
2
Moreover, the effect of real gas for small angle-of-attack case results in small downwardforce moment, whereas that for large angle-of-attack case results in small upward force moment.
此外，小攻角时真实气体效应产生小低头力矩，而大攻角时产生小抬头力矩。
3
Gravity constantly tugs downward on a slope, but only when gravity's force exceeds the strength of the rocks, soils, and sediments composing the slope does land begin to slide down hill.