Influence of Rock Properties on Structural Failure Probability—Caprock Shale Examples from the Horda Platform, Offshore Norway

In any geological subsurface fluid injection, a viable top seal is required to contain the vertical movement of injected plume. However, integrity assessment challenging because uncertainties possessed by various parameters. A probabilistic solution might be more appropriate when significant are present. this study, we evaluate Drake shale caprock structural reliability using stochastic method. primary in Aurora CO2 storage site, located Horda Platform area northern North Sea. Based on lithological variations, divided into two parts designated upper and lower units. Six model scenarios from units have been tested. The failures varying estimated First-Order Reliability Method (FORM). Formation shows considerably low probability failure (~0) with high index initial stress-state condition after-injection scenarios. Moreover, parameter sensitivity study indicates that horizontal stress cohesion most influential input parameters during estimation. Comparative analysis between properties reveals rock strength such as friction angle strongly dictate comparing formations values not correlatable; hence, formation-specific recommended.