Reliable assessment of fault stability is key for safe CO₂ storage in a saline aquifer in fault-bounded structures. The Alpha structure located in the Vette fault's footwall in the Smeaheia area, offshore Norway, is one of the potential CO₂ storage sites with a fault-bounded three-way closure. Assessing fault stability in the Smeaheia area is challenging because of the uncertainties associated with the subsurface fault properties (i.e., fault rock lithologies, strength and geometry of faults, etc.). Besides, CO₂ injection-related pore pressure changes is another critical factor for mechanical deformation and potential failure. We employed a stochastic analytical approach to assess the probability of Vette fault failure using the Monte Carlo Simulation (MCS) and First Order Reliability Method (FORM). The possible fault smear scenarios of the Vette fault zone are evaluated by interpreting the seismic section and the detailed geological understanding. Each scenario's likelihood and the corresponding probability of failure are then integrated stochastically using an event tree method. Overall, Vette fault's system reliability shows a good to average performance range, which has a system probability of failure between 10⁻³ to 10^-4. This finding suggests that the Vette fault will likely act as a potential barrier during CO₂ injection into the Alpha structure. Moreover, the sensitivity study reveals that the stresses (both horizontal and vertical) and fault rock strength (i.e., cohesion and friction angle) are the most crucial parameters to characterize uncertainty reduction.

可靠地评估断层稳定性是在断层界定结构中的盐水层中安全存储CO _2的关键。位于挪威近海Smeaheia地区Vette断层下盘的Alpha结构是潜在的CO ₂封存地点之一，其断层边界为三向闭合。由于与地下断层性质相关的不确定性（例如，断层岩石岩性，断层强度和几何形状等），评估斯梅厄亚地区的断层稳定性具有挑战性。此外，CO ₂注入相关的孔隙压力变化是导致机械变形和潜在破坏的另一个关键因素。我们采用了一种随机分析方法，使用蒙特卡罗模拟（MCS）和一阶可靠性方法（FORM）来评估维特故障的可能性。通过解释地震剖面和详细的地质认识，评估维特断层带可能出现的断层涂片情况。然后，使用事件树方法随机集成每个方案的可能性和相应的失败概率。总体而言，维特故障的系统可靠性显示出良好的平均性能范围，该系统的故障概率为10 ^-3到10 ^-4。这一发现表明，维特断裂可能会在将CO ₂注入Alpha结构期间充当潜在的屏障。此外，敏感性研究表明，应力（水平和垂直）和断层岩石强度（即内聚力和摩擦角）是表征不确定性降低的最关键参数。