So far, most work on VE models for CO2 storage has either assumed incompressible CO2, or only considered lateral variations in CO2 density. In our present work, we have extended the VE framework to permit the full modelling of CO2 compressibility in the VE setting, including vertical density changes. We have:
* Derived the upscaled VE equations with compressibility, and investigated the resulting effects;
* quantifid the importance of such effects depending on local temperature and pressure conditions;
* compared different models (incompressible, laterally compressible and fully compressible) in the simulation of some sample scenarios.
* Discussed practical computational aspects and proposed some quick approximations.