Equilibrium temperatures based on log data acquired during drilling slops in the Los Azufres geothermal held were used to study the relationship between temperature, depth and conductive heat flow that differentiate production from non-production areas. Temperature and thermal conductivity data from 62 geothermal wells were analyzed, displaying temperature-depth, gradient-depth, and ternary temperature-gradient-depth plots. In the ternary plot, the production wells of Los Azufres are located near the temperature vertex, where normalized temperatures are over 0.50 units, or where the temperature gradient is over 165 degreesC/km. In addition, the temperature data were used to estimate the depth at which 600 degreesC could be reached (5-9 km) and the regional background conductive heat flow (approximate to 106 mW/m(2)). Estimates are also given for the conductive heat flow associated with the conductive cooling of an intrusive body (approximate to 295 mW/m(2), and the conductive heat flow component in low-permeability blocks inside the reservoir associated with convection in limiting open faults (from 69 to 667 mW/m(2)). The method applied in this study may be useful to interpret data from new geothermal areas still under exploration by comparing with the results obtained from Los Azufres. (C) 2001 CNR. Published by Elsevier Science Ltd. All rights reserved.