Isabel Edmundson, Atle Rotevatn, Roy Davies, Graham Yielding, Kjetil Broberg

Evidence of hydrocarbon leakage has been well documented across the SW Barents Sea and is commonly associated with exhumation in the Cenozoic. However, further study is required to understand what specific mechanism(s) facilitate such leakage, and why this occurs in some locations and not others. We use seismic and well data to quantify fault- and top-seal strength based on mechanical and capillary threshold pressure properties of fault and cap-rocks. Magnitude and timing of fault slip are measured to acknowledge the role that faults play in controlling fluid flow. Results strongly indicate that across-fault and top-seal breach by capillary threshold pressure, and top-seal breach by mechanical failure are highly unlikely to have caused hydrocarbon leakage. Instead, top-seal breach caused by both tectonic reactivation of faults and fault dilation associated with de-glaciation processes is likely to have facilitated widespread hydrocarbon leakage from structural traps. The results presented herein have implications for understanding mechanisms and locations of hydrocarbon leakage from structural traps across basins worldwide. This is particularly important for exploration and production of hydrocarbons since seal failure is the main cause of dry wells.