TOUGH2 is a general-purpose numerical simulator for multi-phase, multi-component fluid and heat flow in porous and fractured media. It uses a multi-phase extension of Darcy's law that includes relative permeabilityAbility to flow or transmit fluids through a porous solid such as rock and capillary-pressure effects and incorporates accurate phase-partitioning and thermo-physical properties of all fluid phases and components. TOUGH2 is capable of dealing with two-phase (liquid, gas), three-component (water, salt, CO2Carbon dioxide) systems in pressure/temperature regimes above the critical pointThe highest temperature and pressure at which a substance can exist as a vapour and liquid phase in equilibrium of CO2Carbon dioxide.