SALT TRANSFER IN FROZEN METHANE HYDRATE-CONTAINING SEDIMENTS DURING THEIR INTERACTION WITH SALT SOLUTIONS
E.M. Chuvilin, V.V. Ekimova, D.A. Davletshina, B.A. Bukhanov, E.O. Krivokhat
Center for Petroleum Science and Engineering, Skolkovo Institute of Science and Technology, Moscow, Russia
Keywords: permafrost, gas hydrate, salt migration, pressure influence, hydrate dissociation, self-preservation, methane emission
Abstract
This study is devoted to experimental modeling of the interaction of frozen hydrate-saturated sandy sediments with salt solutions at subzero temperatures. It is shown that the migration of salt ions in frozen hydrate-containing sands is more active than in frozen hydrate-free sands. Gas pressure proves to be one of the main factors controlling the intensity of migration of salt ions in frozen sands containing gas hydrates in contrast to frozen hydrate-free sands. With an increase in gas pressure and a decrease in temperature, the intensity of salt transfer in frozen hydrate-containing sands decreases, while the preservation of pore hydrates increases. Based on experimental data, the parameters of salt transfer in frozen hydrate-containing sand (salt flux density, diffusion coefficient) depending on gas pressure and ambient temperature have been obtained for the first time.
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