Gas Equilibria for the Los Azufres (Michoacan) Geothermal Reservoir, Mexico

Abstract

Gas data of the bos Azufres geothermal field were analyzed by using a method based on equilibrium of the Fischer- Tropsch reaction and on the combined pyrite-hematite and pyritemagnetite reactions. Re servoir temp era t ure and reservoir excess sfeam were estimated for initial and present conditions in some representative wells. This method was very useful in estimating reservoir temperatures in vapor producing wells. It was found that as the well produces a smaller fraction of water, the reservoir temperature estimation agrees qualitatively with results from the cationic composition geothermometer. For wells dominated by liquid it is seen that reservoir temperature estimations agree with sim ula tor temperatures. Resuits indicate a decrease in reservoir temperatures in the south zone of the field where intensive reinjection takes place.