水平井管柱下入摩阻分析及应用

Analysis of friction on drill string in horizontal drilling.

水平井造斜后井迹弯曲，使管柱入井时受到的阻力远比直井大，给钻井作业增加了难度，因此对管柱摩擦阻力的分析计算是保证管柱顺利入井的关键。通过建立管柱受力平衡方程，推导出水平井管柱入井时摩阻计算的力学模型，分析计算了在稳定和旋转方式下管柱入井时的大钩载荷和井口扭矩等重要技术参数的解析公式。实例计算分析表明，摩擦阻力计算结果可为钻井设备选型、优化管柱参数和井身结构以及选择下入方式提供可靠依据。

To ensure the drill string tripping smoothly in horizontal drilling, the friction on the string must be analyzed and calculated. By establishing force equilibrium equations, a mechanical model for calculating the friction on the string is set up, and the analytical formulas for calculating the hook load and wellhead torque when the string is tripped in. An example of friction calculation shows that the calculation results provide a basis for the selection of drilling equipment, optimization of drillstem parameters and wellbore structure, and the selection of tripping modes of the drill string.