ESTIMATING THE SORBED WATER CONTENT DURING GAS HYDRATE DECOMPOSITION IN PARTIALLY SATURATED SANDSTONE ACCORDING TO THE ANALYSIS OF NUCLEAR RELAXATION TIME SPECTRA
M.Y. Shumskayte1, T.A. Yanushenko1, V.G. Smirnov2, N.A. Golikov1
1Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
2Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
Keywords: Gas hydrate, sorbed water, nuclear magnetic resonance, longitudinal and transverse relaxation times
Abstract
We have estimated the proportion of sorbed water converted to ice and hydrate during the interaction of wet sand samples with methane by using the nuclear magnetic resonance (NMR) relaxometry method. There is a thin film of strongly bound water in small pores at the rock-fluid interface. This water does not freeze at the subzero temperatures achieved during the experiment; its amount remains constant without regard to the water content in a sample. We have calculated the amounts of strongly bound water and water converted to ice and hydrate for all samples. Based on the established hydrate stoichiometry, we have calculated the amount of methane converted to hydrate. Analysis of the obtained data has revealed the optimal water content in a sample, which results in the greatest amount of hydrate formation.
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