SAGD双水平井水平段轨迹质量评价方法

双水平井SAGD技术要求注汽井与生产井的水平段轨迹保持平行。如果水平段存在较大轨迹偏差,注采井间的热连通较为困难,增加循环预热时间,影响SAGD井组的生产效果。为定量评价该类型井组的井眼轨迹质量,首次提出可用于表征SAGD双水平井井眼轨迹质量的4个新概念:生产井靶区钻遇率、注汽井垂直距离合格率、注汽井水平偏距合格率和双水平井平行度。根据双水平井间的空间几何关系并考虑靶区误差允许范围,推导出上述概念的解析计算模型。实例分析表明这几种合格率可以定量化评价SAGD双水平井的水平段轨迹质量的优劣等级,与轨迹图形反映情况较为吻合。

Explorations on evaluation method for trajectory quality of horizontal section of SAGD double horizontal well

The double horizontal well SAGD technology requires that the horizontal section trajectory of steam injection well remains parallel to that of production well. If the horizontal section has relatively large deviation in trajectory, the thermal connection between injection-production wells will become relatively difficult, the cyclic preheating time will increase, and the production effect of SAGD well group will be affected. In order to evaluate the wellbore trajectory quality of such type of well group in a quantitative manner, the following 4 new concepts which can be used to indicate the wellbore trajectory quality of SAGD double horizontal well have been brought forth , production well target area encountering rate, steam injection well vertical distance pass rate, steam injection well horizontal deviation pass rate and double horizontal well parallelism. On the basis of the special geometrical relation between two horizontal wells and in consideration of the permissible error range of target area, the analytical calculation model for the above-mentioned concepts has been derived. The analysis on actual cases indicates that, these pass rates can evaluate the grade of horizontal section trajectory quality of SAGD double horizontal wells in a quantitative manner, and is relatively consistent with the situation reflected by trajectory figure.