By the stress analysis of the differential element under different displacement modes, it is supposed that the displacement mode only influences the equivalent internal friction Angle of interlayer.
对不同位移模式下水平微分单元进行受力分析，认为位移模式只影响了层间等效内摩擦角。
2
In this paper, the differential equation for the frictional resistance on the drill string in branch horizontal Wells was established and the total drill string friction during tripping was got.
本文建立了在水平分支井眼中的钻柱摩擦阻力微分方程，并得到了在起、下钻过程中钻柱的总摩阻。
3
The paper establishes the general differential equations about elastic liner wear problem of mult-rope friction hoist considering the differences of rope's length and rope grooves.