实钻井眼轨迹视投影长度的计算方法

Calculation of apparent projection length of actual wellbore trajectory

垂直剖面图是显示实钻井眼轨迹的重要方法,其关键在于计算实钻井眼轨迹在设计柱面上的投影曲线。根据几何学原理得到了投影计算的一般方程。并对井段曲线类型为直线、圆柱螺线、圆弧等几种常用情况进行了详细的分析,得到了投影点参数的计算公式。计算实例表明。在实际钻井过程中,利用视投影长度绘制三维井眼实钻轨迹的垂直剖面图可以直观地对比实钻井眼轨迹与设计井眼轨迹的吻合程度,从而起到较好的指导井眼轨迹预测和控制的作用。

The vertical profile is an important way to show actual wellbore trajectory.It provides a projection curve of actual drilling trajectory on design plane.A general equation of projection calculation is derived from geometric theory. Common types of wellbore curves such as straight line,cy- lindrical helical and arc are analyzed in details,thus deriving a calculation equation for projection point.Calculation eases indicate that in the process of actual drilling,the vertical profile of 3D wellbore trajectory mapped by apparent projec- tion length can visibly compare the matching degree of actual drilling trajectory with the design trajectory,thus playing a good guide in wellbore trajectory prediction and controlling.