One-Dimensional Heat Sweep and Fluid Mixing at the Los Azufres Geothermal Field, Mexico

Abstract

The SGP one-dimensional heat sweep model has been adapted to evaluate the potential for thermal breakthrough of reinjected fluids i n the northern and southern zones the Azufres geothermal field in Michoacan, Mexico. The model was used in linear mode in the southern zone between two 'wells designated for production and reinjection to evaluate the effect of variable mixing ratio of sweep to reservoir flow, the latter at variable cooldown rate. The output data are used to estimate the approximate time t o cooldown of produced fluid t o 170?C which corresponds to the minimum inlet pressure to the wellhead generator turbines. In the northern zone, linear and radial flow modes were compared to examine the potential for premature cooldown across line of newly drilled wells as a function of dispersion angle from an existing reinjection well to the zone of four production wells at the three 5 wellhead generators. The data show a significant range potential cooldown times based on the range of parameter values assumed for the reservoir.