Open AccessImaging methane hydrates growth dynamics in porous media using synchrotron X‐ray computed microtomography
Author(s) -
Kerkar Prasad B.,
Horvat Kristine,
Jones Keith W.,
Mahajan Devinder
Publication year - 2014
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1002/2014gc005373
Subject(s) - hydrate , clathrate hydrate , methane , nucleation , porosity , aqueous solution , mineralogy , synchrotron , geology , materials science , chemical engineering , chemistry , composite material , optics , physics , organic chemistry , engineering
Abstract Commercial‐scale methane (CH 4 ) extraction from natural hydrate deposits remains a challenge due to, among other factors, a poor understanding of hydrate‐host sediment interactions under low‐temperature and high‐pressure conditions that are conducive to their existence. We report the use of synchrotron X‐ray computed microtomography (CMT) to image, for the first time, time‐resolved pore‐scale methane CH 4 hydrate growth from an aqueous solution containing 5 wt % barium chloride (BaCl 2 ) and pressurized CH 4 hosted in glass beads, all contained in an aluminum cell with an effective volume of 3.5 mL. Multiple two‐dimensional (2‐D) cross‐sectional images show CH 4 hydrates, with 7.5 µm resolution, distributed in patches throughout the system without dependence on distance from the cell walls. The time‐resolved three‐dimensional (3‐D) images, constructed from the 2‐D slices, exhibited pore‐filling hydrate formation from dissolved CH 4 gas, similar to natural CH 4 hydrates (sI) in the marine environment. Furthermore, the 3‐D images show that the aqueous phase was the wetting phase of the glass beads, i.e., the host and the formed hydrate were separated by an aqueous layer. These results provide some fundamental understanding of the nucleation phenomenon of gas hydrate formation at the pore scale. Pore‐filling CH 4 hydrate growth is likely to result in a reduced bulk modulus, and thus, could affect seafloor stability during the reverse phenomenon, i.e., dissociation of natural hydrate deposits.