Empirical expressions for gas hydrate stability law, its volume fraction and mass-density at temperatures 273.15 K to 290.15 K

Type Article
Date 2008-03
Language English
Author(s) Lu Zhengquan1, 2, Sultan NabilORCID1
Affiliation(s) 1 : IFREMER, Ctr Brest, Dept Marine Geosci, F-29280 Plouzane, France.
2 : Chinese Acad Geol Sci, Inst Mineral Resources, Beijing 100037, Peoples R China.
Source Geochemical Journal (0016-7002) (Terrapub), 2008-03 , Vol. 42 , N. 2 , P. 163-175
WOS© Times Cited 19
Keyword(s) Empirical expressions, Mass density, Fraction out of pore space, Stability law, Gas hydrate
Abstract A series of empirical expressions for predicting gas hydrate stability, its volume fraction out of pore space and gas hydrate mass-density were established in different systems in consideration of gas composition (CH4, C2H6, H2S) and salinity (NaCl, seawater), and pore size at temperature between 273.15 and 300 K, based on our gas hydrate thermodynamic model (Sultan et al., 2004b, c). Six of the developed expressions for predicting gas hydrate stability were validated against the available published experimental data and they were also compared with other models. At temperature 273.15 to 290.15 K, the ARDPs (Average Relative Deviation of Pressures between the prediction and the experimental data) have shown that these empirical expressions are in agreement with the experimental data as well as other models, indicating their reliability of predicting gas hydrate stability for these systems. At higher temperatures, the empirical predictions for gas hydrate stability do not well reproduce the experimental data, because they are based on van der Waals model. The empirical expressions for predicting gas hydrate stability in the systems of CH4 + H2S + H2O, CH4 + seawater + poresize, CH4 + H2S + NaCl and CH4 + CO2 + NaCl, and for evaluating gas hydrate fraction and its density need further validation due to lack of available published experimental data. However, the empirical expressions for gas hydrate fraction and its density show that the effects of pore size and salinity are negligible; gas hydrate fraction will increase if methane concentration continuously increases relatively in excess of methane solubility and decreases with pressure within gas hydrate stability zone, which is well consistent with data of natural gas hydrates in Cascadia; gas hydrate density tends to increase with ethane percentage and decrease with pressure.
Full Text
File Pages Size Access
publication-4958.pdf 26 165 KB Open access
Top of the page

How to cite 

Lu Zhengquan, Sultan Nabil (2008). Empirical expressions for gas hydrate stability law, its volume fraction and mass-density at temperatures 273.15 K to 290.15 K. Geochemical Journal, 42(2), 163-175. Open Access version : https://archimer.ifremer.fr/doc/00000/4958/