Abstract: During the process of directional drilling,the direction of well trajectory and its change are key parameters to monitor and control a well trajectory.As an important part of monitoring and controlling a well trajectory,the path-correction planning is generally required to reach a desired direction at its target.According to the characteristics of directional drilling technology,a three-section profile with two planar turns and one straight line is constructed in this paper to solve the problem on path-correction planning with the given direction in theory,which lays a foundation for effectively monitoring and controlling a well trajectory.The solving process of the design method proposed in this paper is uniform convergent due to avoiding solving the constraint equations set.All of the formulas are theoretically exact solutions,so the universal significance,computational accuracy,stability and convergence have been fully guaranteed.This method can be widely applied to planning directional wells,horizontal wells,extended-reach wells and multiple target wells while drilling.

Key words: drilling theory, mathematical model, wellbore trajectory, design calculation, directional well, horizontal well, extended-reach well, multiple target well

摘要： 在定向钻进过程中,井眼方向及其变化规律是井眼轨道监测与控制的关键参数.修正轨道设计作为井眼轨道监控的重要组成部分,对修正设计目标点的井眼方向往往有一定的要求.根据定向钻井工艺技术的特点,本文构造出了具有两个圆弧段和一个直线段的三段式剖面,从而解决了给定井眼方向条件下的修正轨道设计问题,为井眼轨道的有效监控奠定了基础.本文的设计方法避开了求解约束方程组,使得求解过程是一致收敛的,并且所有计算公式在理论上都是精确解,因此其普适性、精确性、稳定性和收敛性得到了保证,可广泛应用于定向井、水平井、大位移井、多目标井的修正轨道设计.

关键词: 钻井理论, 数学模型, 井眼轨道, 设计计算, 定向井, 水平井, 大位移井, 多目标井