Summit 2021 Dr Eric Mackay Compositional modelling for CCS and hydrogen storage integrity
Dr. Eric Mackay, Heriot-Watt University Compositional modelling for CCS and hydrogen storage integrity A feature of carbon dioxide injection and of hydrogen injection and recovery is that the injected gases may dissolve in the in situ fluids, and the in situ fluids may mix with or evaporate into the injected gases. These processes can lead to loss of integrity of the near well pore space, or impact the purity of any recovered gas. To capture these effects requires compositional simulation, where the components that may exchange between phases, such as CO2, H2 and H2O are included in the Equation of State, as well as the modelling of dissolution of CO2 and H2 in the aqueous phase. The dissolved gases may then trigger predominantly geochemical reactions in the case of CO2, and predominantly biological reactions in the case of H2. During this talk we present an example of modelling of CO2 injection into a saline aquifer, water evaporation and precipitation of sodium and chloride as halite in the near well zone, together with possible remedial actions. We also illustrate the retardation in the displacement of components due to partitioning between phases during H2 storage where CO2 is used as a cushion gas, and the implications for the purity of the produced H2.
Dr. Eric Mackay, Heriot-Watt University Compositional modelling for CCS and hydrogen storage integrity A feature of carbon dioxide injection and of hydrogen injection and recovery is that the injected gases may dissolve in the in situ fluids, and the in situ fluids may mix with or evaporate into the injected gases. These processes can lead to loss of integrity of the near well pore space, or impact the purity of any recovered gas. To capture these effects requires compositional simulation, where the components that may exchange between phases, such as CO2, H2 and H2O are included in the Equation of State, as well as the modelling of dissolution of CO2 and H2 in the aqueous phase. The dissolved gases may then trigger predominantly geochemical reactions in the case of CO2, and predominantly biological reactions in the case of H2. During this talk we present an example of modelling of CO2 injection into a saline aquifer, water evaporation and precipitation of sodium and chloride as halite in the near well zone, together with possible remedial actions. We also illustrate the retardation in the displacement of components due to partitioning between phases during H2 storage where CO2 is used as a cushion gas, and the implications for the purity of the produced H2.