Contactless probing of polycrystalline methane hydrate at pore scale suggests weaker tensile properties than thought

• Published in: Nature Communications
• Main Authors: Atig, Dyhia, Broseta, Daniel, Pereira, Jean-Michel, Brown, Ross
• Other Authors: Laboratoire des Fluides Complexes et leurs Réservoirs (LFCR), Centre National de la Recherche Scientifique (CNRS)-Université de Pau et des Pays de l'Adour (UPPA)-TOTAL FINA ELF, Laboratoire Navier (NAVIER UMR 8205), École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel, Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux (IPREM), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Pau et des Pays de l'Adour (UPPA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: envir; geo; Methane hydrate; permafrost
• Online Access: https://doi.org/10.1038/s41467-020-16628-4; https://hal-univ-pau.archives-ouvertes.fr/hal-02884447/file/s41467-020-16628-4.pdf; https://hal-univ-pau.archives-ouvertes.fr/hal-02884447

International audience Methane hydrate is widely distributed in the pores of marine sediments or permafrost soils,contributing to their mechanical properties. Yet the tensile properties of the hydrate at porescales remain almost completely unknown, notably the influence of grain size on its owncohesion. Here we grow thinfilms of the hydrate in glass capillaries. Using a novel, con-tactless thermal method to apply stress, and video microscopy to observe the strain, weestimate the tensile elastic modulus and strength. Ductile and brittle characteristics are bothfound, dependent on sample thickness and texture, which are controlled by supercooling withrespect to the dissociation temperature and by ageing. Relating the data to the literaturesuggests the cohesive strength of methane hydrate was so far significantly overestimated.