Potentially exploitable supercritical geothermal resources in the ductile crust

Utilizing supercritical geothermal systems: a review of past ventures and ongoing research activities

“…These studies coupled existing geomodeling tools to various simulators via open-source meshing software, e.g., MeshIt . The goal was to extend the predictive capabilities of existing TH-coupled simulation (Jacquey and Cacace 2016;Watanabe et al 2017) on the lifetime performance of a reservoir by including additional mechanical and chemical feedbacks.…”

“…One key aspect of this environment is retrograde solubility of quartz-this might result in the sealing of any fractures generated (Fournier 1991;Saishu et al 2014;Tsuchiya and Hirano 2007). However, on the basis of a new set of laboratory experiments on fractured granites, Watanabe et al (2017) suggest that there is not a step-function decrease in permeability associated with the brittle-ductile transition, and that potentially exploitable resources may occur in nominally ductile granitic crust at temperatures of 375-460 °C and depths of 2-6 km. Recent studies have demonstrated that wells that tap supercritical fluids could have much higher productivities due to the high fluid enthalpies, which could make deeper and hotter wells economically attractive (e.g., Friðleifsson et al 2007).…”

Volatile Degassing From Magma Chambers as a Control on Volcanic Eruptions

“…Recent compilations of deep crustal permeability measurements (Achtziger‐Zupančič et al, ; Ingebritsen & Gleeson, ) clearly show that the permeability‐depth profiles of tectonically quiescent and active regions are markedly different with much larger permeability in active regions. Besides, in situ measurements of permeability in volcanic systems from drilling projects (Fridhleifsson et al, ; Ikeda et al, ; Reinsch et al, ) and lab experiments also suggest nonnegligible permeability even at temperatures higher than the brittle‐ductile transition (∼>500 °C; Watanabe, Numakura, et al ; Watanabe, Egawa, et al ).…”

Permeability Evolution in Variably Glassy Basaltic Andesites Measured Under Magmatic Conditions

“…Thus, the expansion of these studies to conditions appropriate to the middle-to lower-conduit requires the implementation of high temperature techniques. So-called in situ permeability measurements have been performed on granites (Moore et al, 1994;Morrow et al, 2001;Summers et al, 1978;Watanabe et al, 2017), amphibolites and gneisses (Zharikov et al, 2003), ophiolites (Coelho et al, 2015), limestone (Bakker et al, 2015;Fischer & Paterson, 1992), marble (Fischer & Paterson, 1992), sandstone (Fischer & Paterson, 1992), and glass-free dacites (Gaunt et al, 2016). However, to date, only one study has addressed the implications of permeability evolution with changing temperature on eruptive behavior, highlighting the competing micromechanisms that act to create and destroy permeable networks in volcanoes (Gaunt et al, 2016).…”