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
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2020
• Subjects: General Physics and Astronomy; General Biochemistry, Genetics and Molecular Biology; General Chemistry; Methane hydrate; permafrost
• Online Access: http://dx.doi.org/10.1038/s41467-020-16628-4; http://www.nature.com/articles/s41467-020-16628-4.pdf; http://www.nature.com/articles/s41467-020-16628-4

Abstract 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 pore scales remain almost completely unknown, notably the influence of grain size on its own cohesion. Here we grow thin films of the hydrate in glass capillaries. Using a novel, contactless thermal method to apply stress, and video microscopy to observe the strain, we estimate the tensile elastic modulus and strength. Ductile and brittle characteristics are both found, dependent on sample thickness and texture, which are controlled by supercooling with respect to the dissociation temperature and by ageing. Relating the data to the literature suggests the cohesive strength of methane hydrate was so far significantly overestimated.