Recharge of Vapour Saturated Geothermal Reservoirs by Injection of Water

Abstract

In this paper we describe the physical controls upon the rate of vaporisation of liquid as it is injected into a hot porous layer. We show that if liquid is injected at a relatively high rate of injection, then a low fraction of the liquid vaporises and the porous layer becomes filled with hot liquid. However, at low rates of injection, a high fraction of the liquid may vaporise. We also describe a new and fundamental instability that can develop at a migrating liquid-vapour interface if the rate of injection is sufficiently small.