井眼轨迹的主法线角及其方程

Principal Normal Angle of Borehole Trajectory and Its Equation

针对井眼轨迹挠曲特性及其变化规律的表征问题,提出了井眼轨迹主法线角的概念及定义,厘清了井眼轨迹弯曲方向与导向钻具定向方向的本质区别。在此基础上,建立了井眼轨迹主法线角的通用方程,并结合常用井眼轨迹模型给出了主法线角的具体计算方法及公式;揭示了不同挠曲参数间的关系,创建了用特性曲线表征井眼轨迹挠曲形态的方法。研究表明:井眼轨迹的主法线角不同于导向钻具的工具面角,基于直角坐标系和极坐标系耦合的特性曲线可表征多组挠曲参数及其相互关系。研究结果厘清了现有理论与技术中的一些模糊认识,发展了井眼轨迹挠曲形态的表征方法。

Based on the deflection behavior and the characteristics of borehole trajectories, a concept and definition of the principal normal angle of a borehole trajectory was proposed in this paper, and the essential difference between the deflection direction of borehole trajectory and the directional orientation of steering tool was clarified. On this basis, the general equation of the principal normal angle of borehole trajectory was established, and the specific calculation method and formula of the principal normal angle were provided in combination with common borehole trajectory models. The relationships among different deflection parameters were revealed, and the method of characterizing the deflection morphology of a borehole trajectory was established using their characteristic curves. The studies show that the principal normal angle of a borehole trajectory is different from the tool face angle of steering tool. Further, the Cartesian coordinate- polar coordinate coupling based characteristic curve can be used to characterize multiple sets of deflection parameters and their relationships. The research results clarified some fuzzy understandings on the existing theories and techniques, and developed a characterization method for the deflection behavior of borehole trajectories.