One-Dimensional Convective and Conductive Geothermal Heat Flow

Abstract

A number of research workers have investigated two- and three-dimensional natural convective heat flow in porous media containing a single-phase fluid. Results indicate that convective heat flow in geothermal reservoirs can be high with low geothermal gradients within the convection cells. Single-phase convection can occur only in two or three dimensions; however, it is evident that steam and hot water sometimes exist simultaneously in geothermal areas. The large difference in density between steam and hot water provides a driving force that tends to segregate the two phases, making countercurrent vertical one-dimensional fluid flow theoretically possible. This paper presents the results of a study of one-dimensional, vertical, two phase, steady-state, geothermal fluid and heat flow. The object of the investigation was to understand the one-dimensional convective heat flow that may occur where conditions have been stable long enough for the flow to approach steady-state. Results presented herein apply to unfractured porous media. Similar results should apply to fractured reservoirs and permeable fault zones. 3 refs., 8 figs.