Vapor Generation in Hot Permeable Rock Through Injection of Water

Abstract

We present a non-linear model to describe vapour generation in a hot, permeable rock through injection of water. We develop similarity solutions describing the steady injection of fluid from a line source. A systematic parameter study has shown that, with other parameters fixed, as (i) the reservoir pressure increases, the mass fraction vaporised decreases; (ii) the reservoir temperature increases, the mass fraction vaporised increases; (iii) as the mass injection rate increases, the mass fraction vaporised decreases; and (iv) as the porosity increases, the mass fraction vaporised decreases. We then present similarity solutions which describe injection from (i) a point source, with the mass flux injected proportional to t l / ' ; and (ii) a planar source, with the mass flux injected proportional to t-'/', where t is the time of injection. These results suggest that for steady injection, the vapour production gradually increases for injection from a point source, and gradually decreases for planar injection. We confirm this prediction with numerical calculations describing the vapour production resulting from steady injection from line, point and planar sources.