We use simplified methods to investigate how uncertainty in geological models affects practical CO₂ storage capacities in large-scale saline aquifers. Our focus is on uncertainties in top-surface elevation, rock properties (porosity, permeability), fault transmissibility, and aquifer conditions (pressure and temperature). To quantify the statistical characteristics of static trapping capacity and dynamic estimates of plume migration, we create hundreds of possible realizations of the geomodel by applying Gaussian-type perturbations to the spatially correlated properties. Two different simplified methods are introduced to reduce the computational cost of simulating migration over thousands of years in all the model realizations, which each spans hundreds of kilometers. First, we use vertical-equilibrium (VE) modelling, which is orders of magnitude faster than solving the 3D flow equations. Second, we introduce a fast look-ahead algorithm that enables us to exit the VE simulation once a pseudo-steady state is reached. This algorithm uses a spill-point analysis of the top-surface's trapping structure to forecast how much CO₂ will eventually become trapped and how much will leak through open boundaries of the formation. This reduces the computational cost significantly, since we seldom need to simulate long-term migration past a few hundred or thousand years.

我们使用简化的方法来调查地质模型中的不确定性如何影响实际的CO ₂大型盐水含水层的储水能力。我们的重点是地表高程，岩石特性（孔隙度，渗透率），断层可传递性和含水层条件（压力和温度）的不确定性。为了量化静态捕集能力和羽流迁移动态估计的统计特征，我们通过将高斯型扰动应用于空间相关属性，创建了数百种可能的地理模型实现。引入了两种不同的简化方法，以减少所有模型实现中数千年来模拟迁移的计算成本，每个模型实现跨数百公里。首先，我们使用垂直平衡（VE）建模，它比解决3D流方程要快几个数量级。第二，我们引入了一种快速预见算法，一旦达到伪稳态，该算法使我们能够退出VE仿真。该算法使用了对顶面陷阱结构的溢出点分析来预测多少二氧化碳₂最终将被困住，有多少会通过地层的开放边界泄漏。由于我们很少需要模拟几百或几千年的长期迁移，因此这大大降低了计算成本。