Brine Displacement and Leakage Detection Using Pressure Measurements in Aquifers Overlying CO2 Storage Reservoirs

Through the use of analytical solutions derived from a simplified geologic model, this paper investigates the magnitude of pressure transients in permeable zones overlying CO2 storage reservoirs associated with brine migration through the sealing cap rock. A wide range of geologic settings and injection parameters is evaluated from which a generalized correlation is constructed to relate the hydrologic properties of the storage reservoir and seal to the magnitude of expected pressure buildups associated with brine migration across the seal. This correlation, referred to as the detection factor (DF), provides insight into the feasibility and interpretation of pressure changes measured in zones overlying CO2 storage reservoirs as a means of monitoring and leakage detection.