Modeling of coupled wellbore-reservoir flow in steam-like supercritical geothermal systems

•A new EOS module (EOS2H) was develop to handle subcritical and steam-like supercritical H2O-CO2 mixtures.•EOS2H was linked to the simulator T2Well to model gas-like sub- and supercritical coupled reservoir-wellbore flow.•T2Well-EOS2H can be used for both field data interpretation and design purposes.•The flow in supercritical wells is more sensitive to wellbore heat losses than in subcritical wells. The capabilities to efficiently model the transport of mass and heat in geothermal reservoirs at supercritical conditions are necessary to support the efforts to explore and utilize supercritical hydrothermal systems, as well as to extend the utilization of existing geothermal fields at greater depths, where supercritical temperatures might be encountered. Similar capabilities are needed to model the flow in wells producing supercritical fluids, possibly in a coupled way with the reservoir flow. As a step in this direction, the new EOS2H module for sub-critical and steam-like super-critical H2O-CO2 mixtures has been linked to T2Well, the extension of the TOUGH2 numerical reservoir simulator developed for the transient modeling of fully coupled wellbore-reservoir flow. The resulting code is verified against simulations performed with other supercritical reservoir simulators and steady-state subcritical and supercritical wellbore flow simulations. It is then used to perform coupled wellbore-reservoir flow simulations at the well-sector scale relevant to the conditions found in well IDDP-1, Krafla, Iceland.