文章基本信息

标题：The Influence of Electrolytes Composition on the Dissociation Rate of Natural Gas Hydrates Obtained in Model Stratum Waters
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作者：L P Kalacheva ; A S Portnyagin
期刊名称：IOP Conference Series: Earth and Environmental Science
印刷版ISSN：1755-1307
电子版ISSN：1755-1315
出版年度：2019
卷号：272
期号：2
页码：1-7
DOI：10.1088/1755-1315/272/2/022174
出版社：IOP Publishing
摘要：The study of the hydrates formation and decomposition kinetics in solutions of electrolytes is of interest due to the possibility of natural gas storing and transporting in a hydrate state, since the presence of impurities in water is inevitable under appropriate industrial processes. The kinetic parameters of decomposition reactions of natural gas hydrates obtained in model solutions simulating the composition and concentration of stratum waters of East Siberian fields are studied. These deposits are located within the Leno-Tunguskaya and Lena-Vilyuiskaya oil and gas provinces (OGP). The deposits of the Leno-Tunguskaya OGP are characterized by abnormally low reservoir temperatures and pressures (10° C and 16 MPa). The stratum waters belong to the chloride-calcium type, and by the type of the predominant cation either to the calcium or to the sodium subgroup of waters. The mineralization of stratum water can reach 400 g / l and higher. The abnormal high reservoir pressure is 36.3 MPa, the temperatures reach +66 °C for deposits of the Lena-Viluiskaya OGP. Mineralization of stratum water is from 40 to 180 g / l, there may be waters of chloride-calcium (subgroups of calcium and sodium) and sodium bicarbonate (subgroup of sodium) types. Therefore, hydrates of natural gas were obtained in model solutions of calcium and sodium chlorides, and also in solutions of sodium bicarbonate. The rate constants of hydrate decomposition reactions are determined by the Erofeev equation. The shape of the kinetic curves of hydrate decomposition depends on the type and degree of the model stratum water mineralization. The values of the constants n for the decomposition reactions of all hydrate samples are greater than one. This means that these reactions occur in the kinetic region, that is, the rate of hydrates decomposition is determined by the rate of physical desorption of the gas from the clathrate lattice. It has been established that the rate of hydrates decomposition increases with increasing mineralization, and it is higher in the presence of calcium chloride solutions than sodium chloride.