中文摘要：

常规轨道优化设计方法多以最短进尺（ 轨道长度）作为最快机械钻速和最低成本的核心目标函数,未考虑地层地质条件空间分布情况及其对钻时的影响,难以达成实际的优化期望.为此,从勘探钻井一体化设计角度,综合利用地层可钻性地震解释资料与工程设计经验,以页岩气井复杂地层常用的5 段式水平井模型为例,建立了岩石可钻性级值与机械钻速的关系;同时基于多种群遗传算法,以最短钻时为优化目标进行了井身轨迹优化设计.分析结果表明：采用考虑 地层因素的最短钻时井身轨道优化方法,可得到日费制合同模式中相对最优轨道设计方案,从而有效降低钻井时间成本.所得结论可为水平井井身轨迹优化设计提供参考.

英文摘要：

In conventional track optimization methods, the minimum drilling footage （track length） is used as the core objective function to realize the fastest drilling with the lowest cost. It is hard to achieve the optimization goal without considering spatial distribution of stratum geological conditions and its influence on the drilling time. Therefore, by taking 5-section horizontal well model commonly used in complicated stratums shale gas wells as example, the relationship between drillability of rock and drilling rate is established in view of integrated design of exploration and drilling and by comprehensive utilization of seismic interpretation data and engineering design ex-periences. In addition, track of the wellbore is optimized by taking the minimum drilling time as the optimization object on the basis of multi-population genetic algorithm. The result of analysis indicates that, the wellbore track optimization method targeted at the minimum drilling time and taking into account of stratum factors could obtain the relatively optimal track design scheme in the contract mode of daily expenses and substantially reduce the drilling time cost. The conclusion obtained could be a reference for optimization design of wellbore track of horizontal wells.