Characterization Methodology for Analysis in Neighboring Productive and Nonproductive Zones of Los Humeros Geothermal Field

Abstract

The study focused on the analysis of two neighboring zones in the Los Humeros geothermal field (LHGF), each one with different characteristic behaviors. A characterization methodology which can be used in geothermal reservoir engineering was designed and applied to study the zones. The static temperature profiles determined in wells located at the studied zone of the field ranged between 300°C and 360°C. From these temperatures, isotherms in the studied area were calculated and these trend to be deeper toward eastern zone of the field. Similarly the thicknesses tend to reduce in this direction. By analyzing the profiles of fluid circulation losses were determined during drilling of wells in this zone, the existence of low permeability in the rock formation was inferred. From the results of transient pressure tests, low permeability was confirmed. A marked difference in the productive characteristics between the wells, in the close neighborhood was also observed.  Behavior of wells also shows tendency to increase in their steam fractions, with the exploitation time. The characterization methodology applied to the studied zones, allows identify that there is a reservoir section with low permeability, but with high temperatures the depth increases.