New SExI tools to evaluate the evolution and anthropic disturbance in geothermal fields: The case of Los Azufres geothermal field, México
Lee’s classification (Lee, K.C., 1996, Proceedings, Twenty-First Workshop SGP-TR-151 on Geothermal Reservoir Engineering: Stanford, California, Stanford University, 85-92; Lee, K.C., 2001, Geothermics, 30(4), 431-442), based on the specific exergetic index (SExI) has been sparsely used in geological sciences as a way to classify a natural energetic resource. Although useful, it does not take into account the modifications induced to a geothermal field by human exploitation, where exergy is not controlled anymore by natural-driven variables but by the anthropic ones.
In this paper we propose a new way to evaluate the energy-exergy dichotomy, taking into account both geochemical (chlorinity) and anthropic (water flow rate, effective well radius) variables applied to a geothermal field (Los Azufres) where intensive data has been gathered during the past three decades. This original approach will allow to understand the past and present, as well as to evaluate the future behavior of a geothermal well and to plan a better exploitation strategy that prevents geothermal fluid exhaustion.