A three-dimensional temperature model of the Acoculco caldera complex, Puebla, Mexico, from the Curie isotherm as a boundary condition. (July 2020)

• Record Type: Journal Article
• Authors: Guerrero-Martínez, Fernando J.; Prol-Ledesma, Rosa María; Carrillo-De La Cruz, Juan L.; Rodríguez-Díaz, Augusto A.; González-Romo, Irving A.
• Is Part Of: Geothermics. Volume 86(2020)
• Publication Date: 2020-07
• Subjects: Geothermal system -- Curie depth -- Numerical modeling -- Finite volume; Hydrogeology -- Periodicals; Geothermal resources -- Periodicals; Énergie géothermique -- Périodiques; GEOTHERMAL ENGINEERING; GEOTHERMAL ENERGY; GEOTHERMAL EXPLORATION; Geothermal resources; Hydrogeology; Periodicals; Electronic journals; 621.44
• DOI: 10.1016/j.geothermics.2019.101794
• Languages: English
• ISSNs: 0375-6505

Abstract

Highlights: Conceptual model of a promising geothermal field in Mexico based on the Curie isotherm and post-caldera intrusions. Estimation of the Curie isotherm based on the de-fractal method to set a boundary condition in a geothermal area. Solution of the steady-state heat transfer equation with radiogenic heat generation in three dimensions. Over 5 million freedom degrees solved with a Conjugate Gradient method in short time. Abstract: Three-dimensional temperature simulations of the Acoculco caldera complex are undertaken to improve our understanding of its thermal regime. This volcanic caldera has been considered a Conduction-Dominated Crystalline-Rock geothermal play based on evidences of low permeability of the formations hosting the heat source. An estimated Curie isotherm at depth is obtained from the de-fractal method to establish the background heat flow in the area. Additionally, local thermal anomalies and radiogenic heat generation are considered. The description of the structures controlling the heat flow is based on limited borehole data along with field observations, it includes stratigraphic columns and fracture zones. The heat transfer equation is solved in steady state with a Finite Volume numerical method and a Conjugate Gradient algorithm. The resulting computational model constitutes a workable instrument to test assumptions on the thermal regime in the Acoculco caldera that can be gradually constrained, as more data become available. Numerical results show that shallow and localized thermal anomalies (750 ° C) lead to geothermal gradients as high as those measured in the field. The thermal anomalies turn out between 3300 and 3800 m below ground surface as the mean depth, shallower than those assumed in previous 1D thermal models in this caldera complex.