Analysis of Reservoir Conditions During Production Startup at the Los Azufres Geothermal Field

Abstract

Since startup of production at the Los Azufres geothermal field in Michoacan, Mexico, in mid-1982, a large amount of production and chemical data has been accumulated. An evaluation of these data was undertaken with two objectives; first, to characterize the wellbore and reservoir conditions during the startup period and second, to establish the initial conditions for observing changes with continued production and planned increased in power generation. The sampling and chemistry data were examined with the goal of reducing uncertainty in the startup period data to improve the ability to observe minimum significant differences. the complied and averaged data provide an overview of the results of two and one half years of operation of the five 5 MWe wellhead units, consisting of two units in the south zone at wells producing essentially all steam and three units in the north zone at wells production two phase fluids. The data averaged over six monthly and annual periods indicate that the thermal drawdown at the field by the five 5 MWe units has been small.