Numerical Modelling of Geothermal Reservoirs Containing Fluids Near Their Therrnodynamic Critical Point

Abstract

This work investigates natural convection in geothermal reservoirs containing water near the thermodynamic critical point. The peculiarity in pure water properties near the critical point and the extent of the critical region for supercritical pressures are shown. PHOENICS commercial computational fluid dynamics (CFD) was used to simulate natural convection in porous media with near critical properties, which are highly temperature dependent. These near-critical properties were modeled by simple algebraic representations. Speculations on the implications of the critical conditions in real geophysical systems are then discussed in view of the results obtained.