Xenon hydrate as an analog of methane hydrate in geologic systems out of thermodynamic equilibrium

View/ Open
Date
2019-05-06Author
Fu, Xiaojing
Concept link
Waite, William F.
Concept link
Cueto‐Felgueroso, Luis
Concept link
Juanes, Ruben
Concept link
Metadata
Show full item recordCitable URI
https://hdl.handle.net/1912/24362As published
https://doi.org/10.1029/2019GC008250DOI
10.1029/2019GC008250Abstract
Methane hydrate occurs naturally under pressure and temperature conditions that are not straightforward to replicate experimentally. Xenon has emerged as an attractive laboratory alternative to methane for studying hydrate formation and dissociation in multiphase systems, given that it forms hydrates under milder conditions. However, building reliable analogies between the two hydrates requires systematic comparisons, which are currently lacking. We address this gap by developing a theoretical and computational model of gas hydrates under equilibrium and nonequilibrium conditions. We first compare equilibrium phase behaviors of the Xe·H2O and CH4·H2O systems by calculating their isobaric phase diagram, and then study the nonequilibrium kinetics of interfacial hydrate growth using a phase field model. Our results show that Xe·H2O is a good experimental analog to CH4·H2O, but there are key differences to consider. In particular, the aqueous solubility of xenon is altered by the presence of hydrate, similar to what is observed for methane; but xenon is consistently less soluble than methane. Xenon hydrate has a wider nonstoichiometry region, which could lead to a thicker hydrate layer at the gas‐liquid interface when grown under similar kinetic forcing conditions. For both systems, our numerical calculations reveal that hydrate nonstoichiometry coupled with hydrate formation dynamics leads to a compositional gradient across the hydrate layer, where the stoichiometric ratio increases from the gas‐facing side to the liquid‐facing side. Our analysis suggests that accurate composition measurements could be used to infer the kinetic history of hydrate formation in natural settings where gas is abundant.
Description
Author Posting. © American Geophysical Union, 2019. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 20(5), (2019):2462-2472, doi:10.1029/2019GC008250.
Collections
Suggested Citation
Fu, X., Waite, W. F., Cueto-Felgueroso, L., & Juanes, R. (2019). Xenon hydrate as an analog of methane hydrate in geologic systems out of thermodynamic equilibrium. Geochemistry Geophysics Geosystems, 20(5), 2462-2472.Related items
Showing items related by title, author, creator and subject.
-
Determining the flux of methane into Hudson Canyon at the edge of methane clathrate hydrate stability
Weinstein, Alexander; Navarrete, Luis; Ruppel, Carolyn D.; Weber, Thomas C.; Leonte, Mihai; Kellermann, Matthias Y.; Arrington, Eleanor C.; Valentine, David L.; Scranton, Mary I.; Kessler, John D. (John Wiley & Sons, 2016-10-13)Methane seeps were investigated in Hudson Canyon, the largest shelf-break canyon on the northern U.S. Atlantic Margin. The seeps investigated are located at or updip of the nominal limit of methane clathrate hydrate ... -
Mass fractionation of noble gases in synthetic methane hydrate : implications for naturally occurring gas hydrate dissociation
Hunt, Andrew G.; Stern, Laura A.; Pohlman, John W.; Ruppel, Carolyn D.; Moscati, Richard J.; Landis, Gary P. (Elsevier B.V., 2012-09-29)As a consequence of contemporary or longer term (since 15 ka) climate warming, gas hydrates in some settings may presently be dissociating and releasing methane and other gases to the ocean–atmosphere system. A key challenge ... -
Primary deposition and early diagenetic effects on the high saturation accumulation of gas hydrate in a silt dominated reservoir in the Gulf of Mexico
Johnson, Joel E.; MacLeod, Douglas R.; Phillips, Stephen C.; Phillips, Marcie Purkey; Divins, David L. (Elsevier, 2022-01-06)On continental margins, high saturation gas hydrate systems (>60% pore volume) are common in canyon and channel environments within the gas hydrate stability zone, where reservoirs are dominated by coarse-grained, high ...