COUPLING CARBON DIOXIDE SEQUESTRATION WITH GEOTHERMAL ENERGY CAPTURE

Carbon dioxide (CO2) sequestration in deep saline aquifers has been widely considered as a means for reducing CO2 emissions to the atmosphere as a counter-measure to global warming. However, rather than treating CO2 just as a waste fluid in need of permanent disposal, its thermodynamic properties suggest that it could also be used as a working fluid in geothermal energy capture that transfers heat more efficiently than water. Therefore, utilizing CO2 may permit more widespread implementation of geothermal power systems and has the benefit of negative greenhouse gas emissions through CO2 sequestration. Here, we present numerical modeling results of coupled CO2 injection into a brine and heat transfer in geothermal reservoirs under conditions relevant for CO2 sequestration with additional geothermal electricity generation. In particular, we examine subsurface flow and heating of the sequestered CO2, cooling of the geothermal reservoir, and changes in pore-fluid pressures under a variety of generalized CO2 injection and production scenarios and reservoir characteristics.