CO2-Brine-Rock Interactions under Long-term High Pressure High Temperature Reactor Treatment of Kizildere Geothermal Reservoir Rocks

Abstract

The geothermal energy sector is on a rise in several countries as geothermal reservoirs provide a source of renewable energy, as well as the means to permanently lock CO_2 into the reservoir rocks for thousands of years. Geological storage of CO2 in geothermal reservoirs should be investigated for the success of the long-term implementation of the coupled geothermal-CO2 injection technology. The complex CO2-brine-rock interactions, which can affect the geochemical, geomechanical and geophysical properties of reservoir rocks, have implications on the CO2 storage potential of the reservoir and affect the efficiency of the long-term carbon storage. A new long-term high-pressure high-temperature laboratory reactor experiment has been designed and implemented, and results have been analysed to characterise the changes in structural, hydrogeological and geomechanical properties of the reservoir rocks and the geochemistry of the reactor fluids when in contact with CO2. The geochemical reactions occurring within the K?z?ldere geothermal reservoir have been modelled using PHREEQC, the results from preliminary analysis match well with the field conditions and those reported by previous researchers.