Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1038/s41598-021-01388-y
Licence creative commons licence
Title (Primary) A laboratory study of hydraulic fracturing at the brittle-ductile transition
Author Parisio, F.; Yoshioka, K.; Sakaguchi, K.; Goto, R.; Miura, T.; Pramudyo, E.; Ishibashi, T.; Watanabe, N.
Source Titel Scientific Reports
Year 2021
Department ENVINF
Volume 11
Page From art. 22300
Language englisch
Topic T8 Georesources
Keywords Geophysics; Geothermal energy; Hydrogeology; Mechanical engineering; Mechanical properties; Volcanology
Abstract Developing high-enthalpy geothermal systems requires a sufficiently permeable formation to extract energy through fluid circulation. Injection experiments above water’s critical point have shown that fluid flow can generate a network of highly conductive tensile cracks. However, what remains unclear is the role played by fluid and solid rheology on the formation of a dense crack network. The decrease of fluid viscosity with temperature and the thermally activated visco-plasticity in rock are expected to change the deformation mechanisms and could prevent the formation of fractures. To isolate the solid rheological effects from the fluid ones and the associated poromechanics, we devise a hydro-fracture experimental program in a non-porous material, polymethyl methacrylate (PMMA). In the brittle regime, we observe rotating cracks and complex fracture patterns if a non-uniform stress distribution is introduced in the samples. We observe an increase of ductility with temperature, hampering the propagation of hydraulic fractures close to the glass transition temperature of PMMA, which acts as a limit for brittle fracture propagation. Above the glass transition temperature, acoustic emission energy drops of several orders of magnitude. Our findings provide a helpful guidance for future studies of hydro-fracturing of supercritical geothermal systems.
Persistent UFZ Identifier
Parisio, F., Yoshioka, K., Sakaguchi, K., Goto, R., Miura, T., Pramudyo, E., Ishibashi, T., Watanabe, N. (2021):
A laboratory study of hydraulic fracturing at the brittle-ductile transition
Sci. Rep. 11 , art. 22300 10.1038/s41598-021-01388-y