Integration of heat-energy recovery and carbon sequestration

► We simulate cold mixed CO2-water injection into a geothermal reservoir. ► We give a set of simulations for a variety of CO2-injection concentrations. ► Reservoir heterogeneities significantly influence heat extraction and CO2 storage. ► The CO2-trapping mechanism is more efficient in the heterogeneous-permeability field. ► Heterogeneity considerably weakens gravity effects.