Abstract

Hydrate-bearing sediments may destabilize spontaneously as part of geological processes, unavoidably during petroleum drilling/production operations, or intentionally as part of gas extraction from the hydrate itself. In all cases, high pore fluid pressure generation is anticipated during hydrate dissociation. This study centered on the destabilization of gas hydrate-bearing sediments in relation to behavioral characteristics and implications, which is induced by thermal changes. A comprehensive formulation is derived for the prediction of fluid pressure evolution in hydrate-bearing sediments subjected to thermal stimulation without mass transfer. The formulation considers pressure and temperature-dependent volume changes in all phases, sediment compressibility, capillarity, and the relative solubilities of fluids. Salient implications are explored through parametric studies. Finally, the analytical formulation is incorporated into a numerical code, and the two-dimensional numerical modeling using finite different method (herein FLAC2D ) is conducted to assess the instability problem in hydrate-bearing sediments, in which a steady-state hot wellbore transfers a heat into surrounding hydrate-bearing sediments, dissociates methane hydrate, and leads to a mechanical failure of sediments.