静态推靠式旋转导向系统三支撑掌偏置机构控制方案

The control scheme for three-pad static bias device of push-the-bit rotary steerable system

随着国内复杂定向井、水平井以及高难度3D井身结构井的增加,对于旋转导向钻井技术的需求也不断增加,而目前国内对静态推靠式旋转导向系统的导向机构控制方法及原理了解很少,展开相应的研究已非常必要。在外筒旋转的条件下,通过力学矢量合成原理以及数学求解分析表明,静态推靠式三液压支撑掌导向工具同时控制3个支撑掌分力的方案不可行;外筒旋转使得三液压支撑掌导向工具存在控制"死区",给出了这种偏置机构最大可使用偏置合力矢量幅值;采用了两支撑掌调整和控制合力矢量的大小和方向,剩余一个支撑掌浮动支撑,并给出了静态推靠式三液压支撑掌导向工具控制算法框图。该框图可为国内科研人员开展该种偏置机构研究提供理论依据。

With the increase of complex directional oil well number, domestic market demand for rotary steerable drilling technology is rising. But in china, the control method and principle of bias unit is not clear base on static push-the-bit rotary steerable system. So research on it should be necessary. The force vector resultant principle and the analysis of mathematical solution show that it is unfeasible to control the force of each pad simultaneously by using static push-the-bit steerable tools. Due to the rotation of sleeves, the static push- the-bit steerable tool exits can not be controlled well. The maximum usable magnitude of bias force vector is presented. According to the control scheme, two pads are adopted to adjust and control the magnitude and orientation of resultant vector, and the other pad extends to hole wall without force. At last, the control arithmetic is presented for the static push-the-bit rotary steerable tool. The block diagram can supply theory basis for some domestic researchers who study this kind of bias unit.