Shale oil and gas fields usually contain many horizontal wells. The key of 3D structural modeling for shale reservoirs is to effectively utilize all structure-associated data (e.g., formation tops) in these horizontal wells. The inclination angle of horizontal wells is usually large, especially in the lateral section. As a result, formation tops in a horizontal well are located at the distinct lateral positions, while formation tops in a vertical well usually are stacked in the same or similar lateral position. It becomes very challenging to estimate shale layer thickness and structural map of multiple formation surfaces using formation tops in horizontal wells. Meanwhile, the large inclination angle of horizontal wells indicates a complicated spatial relation with shale formation surfaces. The 3D structural modeling using horizontal well data is much more difficult than that using vertical well data. To overcome these new challenges in 3D structural modeling using horizontal well data, we developed a method for 3D structural modeling using horizontal well data. The main process included (1) adding pseudo vertical wells at formation tops to convert the uncoupled formation tops to coupled formation tops as in vertical wells, (2) estimating shale thickness by balancing the shale thickness and dip angle change of a key surface, and (3) detecting horizontal well segments landing in the wrong formations and adding pseudo vertical wells to fix them. We used our improved method to successfully construct two structural models of Longmaxi-Wufeng shale reservoirs at well pad scale and shale oil/gas field scale. Our research demonstrated that 3D structural modeling can be improved by maximizing the utilization of horizontal well data thus optimizing the quality of the structural model of shale reservoirs.

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使用水平井数据进行页岩储层 3D 结构建模：主要问题和改进方法

页岩油气田通常包含许多水平井。页岩储层 3D 构造建模的关键是有效利用这些水平井中所有与构造相关的数据（例如，地层顶部）。水平井的倾角通常较大，特别是在侧井段。因此，水平井的地层顶部位于不同的横向位置，而垂直井的地层顶部通常位于相同或相似的横向位置。使用水平井的地层顶部估计多个地层表面的页岩层厚度和结构图变得非常具有挑战性。同时，水平井的大倾角表明与页岩地层表面存在复杂的空间关系。使用水平井数据进行 3D 结构建模比使用垂直井数据要困难得多。为了克服使用水平井数据进行 3D 结构建模的这些新挑战，我们开发了一种使用水平井数据进行 3D 结构建模的方法。主要过程包括：（1）在地层顶部增设假直井，将非耦合地层顶部转化为垂直井中的耦合地层顶部；（2）通过平衡关键面的页岩厚度和倾角变化来估算页岩厚度； (3) 检测错位水平井段，增加伪直井进行修复。我们使用改进的方法成功构建了井场规模和页岩油气田规模的龙马溪-五峰页岩储层两种构造模型。