The effects of disseminated methane hydrate on the dynamic stiffness and damping of a sand

Abstract

Methane hydrates are ice-like compounds that can exist only under restricted thermobaric conditions, at low temperatures or under high ambient pressure. They are important because of their potential contributions as a future source of energy, to global warming, and as a possible trigger for long run-out submarine slope instability. This paper describes laboratory experiments to synthesise disseminated methane hydrates and to characterise them under small-strain dynamic loading in the resonant column apparatus. The effects of depositing varying quantities of methane hydrate within a sand are investigated by reference to their shear and bulk modulus, and damping, over a range of isotropic effective stress. Results are compared with those obtained on the same sand without hydrate bonding and after dissociation.