Fault seal analysis of a natural CO2 reservoir

For potential CO2 storage sites it is crucial to know if faults will act as flow baffles or if CO2 will be able to migrate out of the reservoir complex. Geomechanical fault seal analysis for a CO2 reservoirs is very similar to hydrocarbon reservoirs. However, fault rock seals have the potential to act very different in a CO2-rock-water system compared to a hydrocarbon-rock-water system. Natural CO2 reservoirs are common in sedimentary basins world-wide and here we present the results of a fault seal analysis, with emphasis on juxtaposition and fault rock seals, of a natural CO2 reservoir from the Colorado Plateau. The reservoir has leaked CO2 for more than 350 ka along faults. Our results show that the existing gas column can overcome the capillary entry pressure of the fault rocks, leading to migration of CO2 to the surface. Additionally, the fault is orientated favourable for reactivation in the current stress field.