Reservoir architecture model and heat transfer modes in the El Tatio-La Torta geothermal system, Central Andes of northern Chile

Abstract

In this work, we present an update for the conceptual model of the El Tatio-La Torta geothermal system, one of the most studied geothermal fields in the Central Andes of South America. Using the structural model reported by Veloso et al. (2019) for northern Chile, the conceptual model proposes a reservoir architecture and heat transfer modes at different scales, connecting the distal catchment area located 15 km east of El Tatio with the outflow of the system: El Tatio geothermal field. The main results of this work are (a) the location of a complex and large reservoir system below El Tatio and La Torta, composed by three main levels named A, B and C, which are connected by the intersection of NW-striking left-lateral and N-striking thrust faults, (b) an explanation for the upflow below La Torta, which is given by the tectono-geothermal environment of the geothermal system, (c) the possible location of the main catchment area at the Tocorpuri basin/caldera, located 15–20 km to the east from the El Tatio geysers, and (d) an explanation for the apparent hydraulic disconnection at El Tatio observed by pressure interference tests, which is coherent with the proposed structural setting for the geothermal field. These results give a physical representation about the fluid circulation and heat transfer modes, connecting La Torta and El Tatio as a unique large-scale geothermal system in the Central Andes.