Fluid Flow and Thermal Anomalies in Naturally Fractured Media: A New Guide for Geothermal Exploration of Crustal Fault Zone

Abstract

In context of global change, Crustal Fault Zones emerge as intriguing geological prospect for geothermal energy resources in naturally deep fractured basements. The occurrence of a positive temperature anomaly is conditioned upon an array of geological and physical parameters. The goal of this study is to proffer a non-exhaustive inventory of some of these parameters: thickness of the fault zone, dip of the fault zone, permeability and tectonic regimes. By employing 2D and 3D numerical modeling, with TH and THM couplings, we can discern different favorable criteria that may serve as guiding exploration: (i) thermal convection is more vigorous where the fault zone thickness is largest, (ii) strike-slip systems foster the extension of positive temperature anomalies, and (iii) vertical and subvertical fault zones concentrate the highest temperature anomalies at shallow depths. Consequently, the identification of these new favorability criteria paves the way for the selection of other fault zones as potential targets for geothermal energy, as it was recently done in Western Europe.