径向水平井转向器内柔性管力学模型研究

Mechanical model for analyzing force conditions of flexible pipe in the whipstock of radial drilling system

准确预测柔性管在转向器内的受力状况是实现超短半径顺利转向的重要保障,也是转向器轨道设计及施工工艺参数设计的重要依据。在刚杆模型的基础上,考虑了管内流体作用力及柔性管与转向器轨道粘卡力等因素,建立了转向器内柔性管的受力分析模型。同时也考虑了轨道偏差对摩阻系数的影响,对摩阻系数进行了修正。模型采用有限差分方法进行计算,并编制了计算程序。模型计算值与室内试验测量值有一定误差,但误差值仅为4.5%,计算精度在允许的范围之内。建立的模型可以用于预测转向器内柔性管的轴向力。

An exact prediction of the force conditions of the flexible pipe in the whipstock is an important guarantee for achievement of the smooth diversion of ultra-short radius as well as an important basis for the design of the whipstock's track and operation technological parameters.On the basis of the rigid-rod model and considering some factors such as the tubular fluid acting force and the viscous sticking force between the flexible tube and the steering track,a force analysis model of the flexible pipe in the whipstock was established.At the same time,the effect of the track deviation on the friction resistance coefficient was taken into account and the coefficient was revised.The model adopted the finite-difference method to conduct a calculation and compiled the calculation program.There exists an error between the model calculation value and the measured value in the laboratory test,but the error is merely 4.5%.The calculation precision falls within the scope of tolerance.The model established can be used to predict the axial force of the flexible pipe in the whipstock.