CLASSIFICATION OF ONE-DIMENSIONAL STEADY-STATE 2-PHASE GEOTHERMAL FLOWS INCLUDING PERMEABILITY VARIATIONS - II - THE GENERAL-CASE

In Part II of this paper the analysis is extended to include both cond uction and non-zero net mass flow. We are able to distinguish between low and high enthalpy two-phase reservoirs, where the former must term inate in single-phase liquid conditions at depth, while the latter may end in single-phase liquid (for low permeabilities), single-phase vap our (for intermediate permeabilities), or can be unstable when extende d (for high permeabilities). If, and only if, both conduction and net mass Row are non-zero a class of models can be identified with the pro perty that a permeability increase (downwards) is associated with a li quid saturation decrease. This provides a prototype for a vapour-domin ated geothermal reservoir. (C) 1998 Elsevier Science Ltd. All rights r eserved.