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

Dyhia Atig (1) , Daniel Broseta (1) , Jean-Michel Pereira (2) , Ross Brown (3)

1 LFCR - Laboratoire des Fluides Complexes et leurs Réservoirs
2 NAVIER UMR 8205 - Laboratoire Navier
3 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux

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.

Domaines: Sciences de l'environnement; Physique [physics]

Dyhia Atig, Daniel Broseta, Jean-Michel Pereira, Ross Brown. Contactless probing of polycrystalline methane hydrate at pore scale suggests weaker tensile properties than thought. Nature Communications, 2020, 11, pp.3379. ⟨10.1038/s41467-020-16628-4⟩. ⟨hal-02884447⟩