Experimental and Theoretical Studies of Liquid Injection into Vapour-Dominated Reservoirs

Abstract

We analyze the injection of liquid into a depleted geothermal reservoir using numerical, analytical experimental techniques. We first investigatethe injection of liquid at the base of a uniformly heated reservoir and show how an ascending liquid layer develops. Ahead of the liquid-vapourinterfacethe temperature rises sharply and, for cases in which the permeability is sufficiently high, the vapour is approximately isobaric. The region immediately behind the advancing liquidinterface is approximately isothermal and therefore, the fraction vaporizing is dependent on the reservoir superheat. When the reservoir is overlain by a supercooled zone, some of the vapour produced at the ascending liquid-vapour condenses. As a result, the amount of newly formed vapour available for subsequent extraction can be significantly reduced.