采用丛式井平台模式是大力开发页岩气重要手段之一，但由于丛式平台井的井距较小，当前井与邻井的交碰风险大，井眼轨道的防碰设计困难。常规的轨道设计方法是，先设计轨道再防碰扫描，直到满足防碰指标。需要进行大量的试算，耗费人力。提出了利用井眼轨迹误差分析理论，计算出满足防碰要求的轨道关键参数，从而提高丛式井井眼轨道设计效率。采用ISCWSA误差模型，分析了轨道关键参数的影响因素。结果表明，丛式井井眼轨道上部平行井眼防碰临界深度与井口间距密切相关，随井口间距增加，临界深度增加。造斜点的位置必须小于防碰临界深度，适当提前造斜有利于井眼防碰。造斜点位置的提前量与造斜率有关，增加造斜点提前量可降低造斜点造斜率要求。同时，建立了平行井眼防碰临界深度、造斜点临界造斜率、造斜点提前量以及稳斜段临界井斜角计算模型，为快速设计出满足防碰要求的井眼轨迹提供了理论手段。

Cluster well platform mode is one of the important means to develop shale gas vigorously. However, due to the small distance of cluster platform wells, the risk of collision between current wells and adjacent wells is high, and the anti-collision design of wellbore trajectory is difficult. The conventional well trajectory design method is to first design the trajectory and then analyze anti-collision until the anti-collision index is met. A lot of trial calculation is required, which consumes manpower. The theory of well trajectory error analysis was proposed to calculate the key parameters of trajectory that meet the requirements of anti-collision, so as to improve the efficiency of cluster well trajectory design. The influence factors of the key parameters of the track were analyzed by using ISCWSA error model. The results show that the critical anti-collision depth of the parallel wellbore above the well trajectory of cluster well is closely related to the wellhead spacing, and the critical depth increases with the increase of the wellhead spacing. The position of the kickoff point must be less than the critical depth of anti-collision, and proper advance kickoff is conducive to anti-collision. The advance of the position of the kickoff point is related to the build-up rate. Increasing the advance of the kickoff point can reduce the requirements for the build-up rate of the kickoff point. At the same time, the calculation models of anti-collision critical depth of parallel wells, critical build-up rate of kickoff point, advance of kickoff point and critical angle of inclination of stable section are established, which provides a theoretical means for quickly designing the well trajectory meeting the anti-collision requirements.