中曲率辐向水平井轨迹设计

普通水平井轨迹由三部分组成：直井段，造斜段，水平段。辐向水平井是水平井系列中的高难度井，它除了有一段水平井段外，还有另外一条或多条分支井段。在实际设计水平井时，首先根据钻探目的及油气藏的空间组合模式设计水平井段，确定始靶点、终靶点及各轨迹控制点的坐标，然后按始靶点轨迹参数反推，设计造斜段的造斜点坐标、造斜率及垂直、水平位移，并确定井口坐标。设计分支井的目的主要是探明倾斜油层的油水界面，分支井段各控制点参数的设计方法与水平段类似。

Design of mid-curved radial horizontal well

An ordinary horizontal well consists of vertical section,curve section and horizontal section. Radial horizontal well is the most complicated one in horizontal well series,it has a major horizontal section and one or several branch sections. The design of a horizontal well includes the steps: 1)designing the horizontal section in the light of drilling target and reservoir configuration,which involves determination of the coordinates of starting point,ending point and control points ; 2 )using the starting-point parameters to calculate well-head coordinate and curved-section parameters:locus coordinates, curvature, vertical and horizontal displacements. Branch sections are designed to ascertain oil-water contact in slant reservoir. Control point parameters of branch sections are designed in the same way for the horizontal section.