Abstract:

The steering force and tool structure provided by the rotary steering tool determine the deflection ability of the tool, which is one of the important evaluation indexes of the tool performance. This paper analyzes the guiding principle of rotary steering tool, carries out mechanical modeling of the orientation actuator, and obtains the periodic variation regularity and scope of the tool steering force. On this basis, the influence of tool structure parameters, friction coefficient and mud pressure difference on steering force is analyzed, which provides theoretical reference for tool structure optimization and buildup rate calculation. The results show that with the increase of friction coefficient, the tool steering force increases slightly but the tool stability decreases significantly, so the friction coefficient should be reduced by packaging and lubrication design. With the increase of the wedge angle, the tool steering stability increases but the steering force decreases, so the relationship between them should be balanced in tool design according to the actual needs. The quality and motion parameters of the moving parts have little influence on the tool steering force, which can be improved by increasing the mud pressure difference and the effective area of the servo cylinder piston.

Key words:

point-the-bit, rotary steering tool, steering force, mechanical analysis

摘要：

旋转导向工具提供的导向力及工具结构决定了工具的实际造斜能力，是工具性能的重要评价指标之一。文章通过对内推指向式旋转导向工具导向执行机构力学建模，给出内推指向式旋转导向工具导向力的计算表达式，分析了工具结构参数、摩擦系数及钻井液压差对工具导向力的影响。研究表明，随摩擦系数增大，工具导向力小幅上升但工具稳定性显著降低，应通过封装和润滑设计减小工具摩擦系数；随工具导向执行机构调整楔块倾角增大,工具导向稳定性提高但导向力减小，在工具设计中应注意平衡二者关系；工具运动件质量和运动参数对工具 导向力几乎没有影响，主要通过增大钻具内外钻井液压差和伺服液缸活塞有效面积来提高工具导向力。

关键词:

指向式, 旋转导向工具, 导向力, 力学分析