井眼弯曲平面倾角对钻头侧向力的影响研究

STUDY ON THE INFLUENCE OF WELL CURVATURE PLANE ANGLE ON SIDE FORCE A CTING ON BIT

井眼轨迹的空间形状是影响钻头侧向力特别是方位力的一个主要因素。文中利用弯曲平面倾角来描述井眼轨迹的弯曲方向，并探讨了弯曲平面倾角对钻头侧向力的影响及其规律。结果表明，弯曲平面倾角和井眼曲率的有机结合可以很好地描述井眼轨迹空间形状对钻头侧向力的影响。当弯曲平面倾角为0°时，钻头上的方位力近似为零，而当弯曲平面倾角接近90°或270°时，钻头上的方位力绝对值最大。在不考虑地层因素的影响时，井眼的弯曲平面倾角及弯曲程度是产生钻头方位力的一个主要因素。在现场井眼轨迹控制过程中，应充分考虑这一特点。

Space configuration of well trajectory is one of the m ajor accounts that determines the lateral force, and especially, the orientation force on bit. T he curvature direction of well path is used to describe hole orientation in this paper, and its influence on bit lateral force, the influencing tendency is also investigated. The results show that the the curvature direction of well path co uld be used effectively to illustrate how the space configuration of well trajec tory affect bit lateral force, combining the use of hole curvature. Specifically , the orientation force on bit is approximately zero when the the curvature dire ction of well path is 0°, and the maximum value appears when the the curvature direction of well path is 90° or 270°. It shows that the curvature direction o f well path and hole curvature are the two major causes that produce orientation force on bit, when formation condition is not taken into consideration. This st udy is helpful for well trajectory control in field drilling.