Stability of water-vapor phase transition in geothermal systems

The problem of normal stability of a phase transition interface for vertical flows in a geothermal reservoir with the water layer lying above the vapor layer is solved. The problem is formulated with account for convective energy transfer, which ensures applicability for arbitrary permeability values. Typical examples of variation of the phase transition interface stability parameters in response to changes in permeability are considered for various geothermal reservoirs.