Thermal Evolution (1984-2005) of the Los Humeros (Mexico) Geothermal Fluids as Indicated by Chemical Geothermometers

Abstract

The thermal evolution of Los Humeros geothermal fluids was estimated by using liquid and gas chemical geothermometers and results indicate two separated fluid entries to the wells: a (∼250°C) liquid produced from a shallower reservoir and a (>300°C) steam produced by a deeper stratum. Both entries were identified by Na/K and SiO₂ geothermometers for the liquid and H₂/Ar for the steam. CO₂/Ar geothermometer seems to provide temperatures of mixed fluids entering the wells. Based on thermal evolution of fluids, multiple fluid entries in wells were characterized while reservoir exploitation-related processes like cooler water entries and condensation phenomena, were also identified.