Kinetic Reactive Transport Modelling of CCS Disaster Scenarios: CO2 or Brine Leakage from a CO2 Reservoir into a Freshwater Aquifer

Abstract

Potential disaster scenarios of CO2 geological storage (CGS) are CO2 escape and brine displacement to protected freshwater aquifers via unexpected pathways. Present study evaluates the geochemical aspects of such events in the vicinity of potential CGS sites in Hungary. This is primarily possible by reactive transport modelling using the open source PHREEQC. Solution and mineral compositions, electrical conductivity and porosity are simulated in time and space. Main results predict an increase of ion-concentrations in the freshwater; some ions may even exceed drinking water limit values either in the case of CO2 and brine leakage. Finally, electrical conductivity of water is suggested to record for a cost-effective, early detection of both scenarios.