Two-front mathematical model of water injection into a steam-saturated geothermal reservoir

Abstract

A mathematical model of the process of water injection into a high-temperature steam-saturated geothermal reservoir is proposed. In the reservoir there is a zone of co-existence of steam and water which is separated from the steam and water zones by moving interfaces (phase transition fronts) whose location is determined in the process of solving the problem. Within the framework of the proposed model the thermodynamic contradiction that exists in the single-front case for low permeabilities, expressed as supercooling of the steam in the corresponding zone ahead of the interface [1, 2], is not observed. With increase in the permeability the two-front solution obtained goes smoothly over into a noncontradictory single-front solution. Neutral curves separating the domains of existence of the different types of solution in parameter space are constructed.