Production Chemistry of Wells in the Southern Part of Los Azufres, Michoacan, Mexico

Abstract

The Los Azufres geothermal field is located in the state of Michoacan in the central portion of the Mexican Volcanic Belt and is divided into two zones: the northern and the southern ones. In this paper, an updated analysis of the wells geochemistry is presented together with a discussion about the main processes that have been occurring in the southern part of this reservoir. The southern zone of the geothermal field is a two-phases system. In the deeper zone the reservoir is of a liquid dominated type. Some wells initially discharged a mixture of steam and water and some of them only produce steam. Most wells produce high enthalpy at their discharge and the dominated aqueous components are sodium, chloride, and potassium. The fluids also contain high concentrations of silica and boron. The main processes observed during the commercial exploitation of the wells are steam loss, cooling and boiling, depending on location of the feed zone. The liquid discharged by the wells is sodium-chloride water with near neutral pH and hot equilibration temperature of about 300?C. On the other hand, the gas composition is derived from magmatic sources, where carbon dioxide (CO2) is the major component of non-condensable gases (NCG).