Crustal fingering facilitates free-gas methane migration through the hydrate stability zone
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31660.full.pdf
Description
Published version
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1.15 MB
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Checksum (MD5)
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Author(s)
Fu, Xiaojing
Jimenez-Martinez, Joaquin
Nguyen, Thanh Phong
Carey, J William
Viswanathan, Hari
Cueto-Felgueroso, Luis
Juanes, Ruben
Date Issued
November 2020
Journal
Proceedings of the National Academy of Sciences of the United States of America
Publisher
Proceedings of the National Academy of Sciences
Citation
Xiaojing Fu, Joaquin Jimenez-Martinez, Thanh Phong Nguyen, J. William Carey, Hari Viswanathan, Luis Cueto-Felgueroso, Ruben Juanes, Crustal fingering facilitates free-gas methane migration through the hydrate stability zone, Proceedings of the National Academy of Sciences Dec 2020, 117 (50) 31660-3166
Version
Final published version
Abstract
© 2020 National Academy of Sciences. All rights reserved. Widespread seafloor methane venting has been reported in many regions of the world oceans in the past decade. Identifying and quantifying where and how much methane is being released into the ocean remains a major challenge and a critical gap in assessing the global carbon budget and predicting future climate [C. Ruppel, J. D. Kessler. Rev. Geophys. 55, 126-168 (2017)]. Methane hydrate (CH4 · 5.75H2O) is an ice-like solid that forms from methane-water mixture under elevated-pressure and low-temperature conditions typical of the deep marine settings (>600-m depth), often referred to as the hydrate stability zone (HSZ). Wide-ranging field evidence indicates that methane seepage often coexists with hydrate-bearing sediments within the HSZ, suggesting that hydrate formation may play an important role during the gas-migration process. At a depth that is too shallow for hydrate formation, existing theories suggest that gas migration occurs via capillary invasion and/or initiation and propagation of fractures (Fig. 1). Within the HSZ, however, a theoretical mechanism that addresses the way in which hydrate formation participates in the gas-percolation process is missing. Here, we study, experimentally and computationally, the mechanics of gas percolation under hydrate-forming conditions. We uncover a phenomenon-crustal fingering-and demonstrate how it may control methane-gas migration in ocean sediments within the HSZ.
MIT Department
Massachusetts Institute of Technology. Department of Civil and Environmental Engineering
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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DOI of Published Version
https://doi.org/10.1073/PNAS.2011064117
