Conceptual Model of the Hveragerdi Geothermal Reservoir Based on Geochemical Data

Abstract

A combined study on the chemistry of geothermal water and steam along with data froin wells results in a conceptual model of the high-temperature geothcrrnal field in southern Iceland. The reservoir water enters the system from the north and flows towards the south. On the way the water cools to mixing with cold groundwater. is confined to the uppermost 200 in upflow zones. Water entering wells at depth is generally equilibrium with secondary minerals. The ratio is higher in water from springs than in water wells due to mixing between geothermal water and old groundwater of a marine origin in upflow zones. The complicated effects of boiling and mixing diminish the value of solute in estimating subsurface temperatures. Three mixing models were applied to evaluate the temperature of water. all indicate an initial temperature of 230-250 Gas geothrnnoineters reflect decreasing temperatures from north and they indicate that the temperature of the reservoir water that enters the iield is 240-250