2-3-2 Pattern formation of THF hydrates growing in sediment models

Abstract

Our group carried out growth experiments of THF hydrates in a mixture of glass beads and the stoichiometric THF−water solution (THF−17H2O) to elucidate the pattern formation mechanism of methane hydrates in oceanic sediments, and succeeded in the formation of four categories of patterns (layered, nodular, disseminated, massive). In the present study, to elucidate the effect of THF diffusion on the hydrate patterns, diluter THF water solution sample mixed with glass beads were used. Experiments were performed as a function of THF concentration and growth rate under conditions of nodular and massive formation in the case of the stoichiometric THF−water solution. As a result, thinner hydrates than the inner thickness of the sample cell grew, when the THF concentration of the sample was decreased. In addition, the facetted hydrates were observed at the lower growth rates. This might be caused by the morphological instability of hydrates in the thickness direction under the influence of THF diffusion field.