Realizable CO₂ storage potential for saline formations without closed lateral boundaries depends on the combined effects of physical and chemical trapping mechanisms to prevent long-term migration out of the defined storage area. One such mechanism is the topography of the caprock surface, which may retain CO₂ in structural pockets along the migration path. Past theoretical and modeling studies suggest that even traps too small to be accurately described by seismic data may play a significant role. In this study, we use real but scarce seismic data from the Gassum Formation of the Norwegian Continental shelf to estimate the impact of topographical features of the top seal in limiting CO₂ migration. We seek to estimate the amount of macro- and sub-scale trapping potential of the formation based on a few dozen interpreted 2D seismic lines and identified faults. We generate multiple high-resolution realizations of the top surface, constructed to be faithful to both large-scale topography and small-scale statistical properties. The structural trapping and plume retardation potential of these top surfaces is subsequently estimated using spill-point (static) analysis and dynamical flow simulation. By applying these techniques on a large ensemble of top surface realizations generated using a combination of stochastic realizations and systematic variation of key model parameters, we explore the range of possible impacts on plume advancement, physical trapping and migration direction. The stochastic analysis of trapping capacity and retardation efficiency in statistically generated, sub-seismic resolution features may also be applied for surfaces generated from 3D data.

对于没有闭合侧向边界的盐分地层，可实现的CO ₂储存潜力取决于物理和化学捕集机制的综合作用，以防止长期迁移出定义的储存区域。一种这样的机制是盖层表面的形貌，它可以沿迁移路径将CO ₂保留在结构袋中。过去的理论和模型研究表明，即使太小而无法用地震数据准确描述的圈闭也可能起重要作用。在这项研究中，我们使用来自挪威大陆架Gassum组的真实但稀少的地震数据来估计顶盖地形特征对限制CO _2的影响移民。我们力求根据几十条经解释的2D地震线和已确定的断层来估计地层的宏观和亚尺度陷获潜力。我们生成顶表面的多个高分辨率实现，构造为忠实于大型地形和小型统计属性。随后使用溢出点（静态）分析和动态流动模拟来估算这些顶表面的结构性捕集和羽流滞后潜力。通过将这些技术应用于由随机实现和关键模型参数的系统变化相结合而生成的大量顶面实现中，我们探索了对羽状推进，物理圈闭和迁移方向的可能影响范围。