煤层气水平分支井轨迹设计新方法

煤层气水平分支井技术已成为科学、高效开发煤层气资源的重要手段，而轨迹设计作为该技术的关键组成部分，直接影响到后期的钻完井作业的成败以及煤层气开发效果。煤层气水平分支井轨迹设计涉及多约束条件下的三维轨迹设计问题，目前国内对这方面的研究虽取得了一定的进展，但仍有待于发展和完善。为此，基于空间圆弧轨道理论，建立了一套适合煤层气水平分支井的三维轨迹设计模型，应用矢量分析理论求得了约束变量间的解析表达式，并提出了配套的轨迹设计计算流程，可以在分支爬高高度和现场工具造斜率约束下，准确、快速地设计出合理的煤层气水平分支井井眼轨迹。根据以上模型，采用现代可视化编程技术开发了煤层气水平分支井井眼轨迹设计软件和井眼轨迹三维可视化软件，并完成了一口双分支煤层气水平井的设计。

A new method of trajectory planning for a horizontal multilateral well in coalbed methane gas reservoirs

Horizontal multilateral well technology in coalbed methane (CBM) reservoirs has become a scientific and efficient technical means for the CBM development. Trajectory planning is a key component of CBM horizontal multilateral well technology, directly affecting the later period drilling and completion. The trajectory planning of a CBM horizontal multilateral well is a three dimensional trajectory design under many constraint conditions. Although the related domestic studies have made some progress, there is still much to improve. Based on the circular orbit space theory, a branch of three dimensional trajectory model for a CBM horizontal multilateral well has been established, the analytical expression among constraint variables is obtained using the vector analysis theory, and the trajectory design calculation process is then proposed. Thus, a reasonable trajectory planning for a CBM horizontal multilateral well can be made accurately and quickly under the constraints of branch climbing height and tools' build up rate. And based on the above model, the modern visual programming technology is used to develop trajectory planning and visualization softwares for a CBM horizontal multilateral well. An example of trajectory planning is finally made herein for one CBM horizontal two lateral well.