TY - JOUR
T1 - Effect of thermal formation/dissociation cycles on the kinetics of formation and pore-scale distribution of methane hydrates in porous media
T2 - a magnetic resonance imaging study
AU - Vasheghani Farahani, Mehrdad
AU - Guo, Xianwei
AU - Zhang, Lunxiang
AU - Yang, Mingzhao
AU - Hassanpouryouzband, Aliakbar
AU - Zhao, Jiafei
AU - Yang, Jinhai
AU - Song, Yongchen
AU - Tohidi, Bahman
N1 - Funding Information:
The authors would gratefully acknowledge Heriot-Watt University for providing the PhD funding for Mehrdad Vasheghani Farahani through James Watt Scholarship.
Publisher Copyright:
© The Royal Society of Chemistry 2021.
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/3/7
Y1 - 2021/3/7
N2 - A magnetic resonance imaging study was conducted to explore the kinetics and spatial characteristics of the thermally induced methane hydrate formation in both synthetic and natural sediment samples. Low-resolution images were taken from the sediment samples during the hydrate formation and dissociation stages of three consecutive thermal cycles and the induction time, hydrate formation rate and duration, spatial distribution of water, and saturation of all co-existing phases were determined in order to understand the effect of the first cycle of the formation/dissociation on the subsequent cycles. The results demonstrate that the induction and hydrate formation times of the second and third thermal cycles decrease due to the memory effect, enhanced dissolution of methane in the aqueous phase and the redistribution of water associated with the first cycle of the hydrate formation and dissociation. Moreover, the hydrate formation proceeds with a fairly smooth and fast trend in the subsequent cycles primarily due to the multiple nucleation events, in contrast with the traditionally believed “fits and starts” manner which was observed for the first cycle. The thermal cycles for the natural sediment sample were compared with those for the synthetic sediment sample in terms of the induction time, hydrate formation behaviour and duration, and spatial distribution to understand how the sediment particle type and size distribution could influence the cyclic hydrate formation/dissociation. High-resolution images were also taken from the samples and used to infer the spatial distribution of methane hydrates, gas and water in pore space after completion of the hydrate formation stage of each thermal cycle, by applying an innovative image analysis approach.
AB - A magnetic resonance imaging study was conducted to explore the kinetics and spatial characteristics of the thermally induced methane hydrate formation in both synthetic and natural sediment samples. Low-resolution images were taken from the sediment samples during the hydrate formation and dissociation stages of three consecutive thermal cycles and the induction time, hydrate formation rate and duration, spatial distribution of water, and saturation of all co-existing phases were determined in order to understand the effect of the first cycle of the formation/dissociation on the subsequent cycles. The results demonstrate that the induction and hydrate formation times of the second and third thermal cycles decrease due to the memory effect, enhanced dissolution of methane in the aqueous phase and the redistribution of water associated with the first cycle of the hydrate formation and dissociation. Moreover, the hydrate formation proceeds with a fairly smooth and fast trend in the subsequent cycles primarily due to the multiple nucleation events, in contrast with the traditionally believed “fits and starts” manner which was observed for the first cycle. The thermal cycles for the natural sediment sample were compared with those for the synthetic sediment sample in terms of the induction time, hydrate formation behaviour and duration, and spatial distribution to understand how the sediment particle type and size distribution could influence the cyclic hydrate formation/dissociation. High-resolution images were also taken from the samples and used to infer the spatial distribution of methane hydrates, gas and water in pore space after completion of the hydrate formation stage of each thermal cycle, by applying an innovative image analysis approach.
UR - http://www.scopus.com/inward/record.url?scp=85102411473&partnerID=8YFLogxK
U2 - 10.1039/d0se01705a
DO - 10.1039/d0se01705a
M3 - Article
AN - SCOPUS:85102411473
SN - 2398-4902
VL - 5
SP - 1567
EP - 1583
JO - Sustainable Energy and Fuels
JF - Sustainable Energy and Fuels
IS - 5
ER -