| Abstract |
The recoverability factors used to estimate resources of hydrothermal convection systems in Nathenson and Muffler (1975) are based on extracting the stored heat from a volume of porous and permeable rock, neglecting recharge of heat by either conduction or movement of water (Nathenson, 1975). The potential for heat recharge by conduction is neglected because it is very small compared to expected rates of production from any volume of rock greater than a few cubic kilometers. Likewise, for most of the hot-water systems of the United States, the natural discharge of thermal waters is low compared to reasonable production rates, and, accordingly, the potential for heat recharge by upflow of hot water to most reservoirs is probably low and can be neglected. The validity of this assumption can be assessed only after extensive production histories have been obtained for a reservoir. those systems in which heat recharge by upflow of hot water is shown to be important, recoverability factors will have to be raised accordingly. Although the recharge potential of heat is neglected, the potential and, in fact, the need for cold water recharge are not. |