A densification mechanism to model the mechanical effect of methane hydrates in sandy sediments
SUMMARY Recent pore‐scale observations and geomechanical investigations suggest the lack of true cohesion in methane hydrate‐bearing sediments (MHBSs) and propose that their mechanical behavior is governed by kinematic constrictions at pore‐scale. This paper presents a constitutive model for MHBS, w...
Published in: | International Journal for Numerical and Analytical Methods in Geomechanics |
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crwiley:10.1002/nag.3038 2024-10-13T14:08:59+00:00 A densification mechanism to model the mechanical effect of methane hydrates in sandy sediments De La Fuente, Maria Vaunat, Jean Marín‐Moreno, Héctor Graduate School of the National Oceanography Centre Southampton 2020 http://dx.doi.org/10.1002/nag.3038 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fnag.3038 https://onlinelibrary.wiley.com/doi/pdf/10.1002/nag.3038 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/nag.3038 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor International Journal for Numerical and Analytical Methods in Geomechanics volume 44, issue 6, page 782-802 ISSN 0363-9061 1096-9853 journal-article 2020 crwiley https://doi.org/10.1002/nag.3038 2024-09-23T04:36:22Z SUMMARY Recent pore‐scale observations and geomechanical investigations suggest the lack of true cohesion in methane hydrate‐bearing sediments (MHBSs) and propose that their mechanical behavior is governed by kinematic constrictions at pore‐scale. This paper presents a constitutive model for MHBS, which does not rely on physical bonding between hydrate crystals and sediment grains but on the densification effect that pore invasion with hydrate has on the sediment mechanical properties. The Hydrate‐CASM extends the critical state model Clay and Sand Model (CASM) by implementing the subloading surface model and introducing the densification mechanism. The model suggests that the decrease of the sediment available void volume during hydrate formation stiffens its structure and has a similar mechanical effect as the increase of sediment density. In particular, the model attributes stress‐strain changes observed in MHBS to the variations in sediment available void volume with hydrate saturation and its consequent effect on isotropic yield stress and swelling line slope. The model performance is examined against published experimental data from drained triaxial tests performed at different confining stress and with distinct hydrate saturation and morphology. Overall, the simulations capture the influence of hydrate saturation in both the magnitude and trend of the stiffness, shear strength, and volumetric response of synthetic MHBS. The results are validated against those obtained from previous mechanical models for MHBS that examine the same experimental data. The Hydrate‐CASM performs similarly to previous models, but its formulation only requires one hydrate‐related empirical parameter to express changes in the sediment elastic stiffness with hydrate saturation. Article in Journal/Newspaper Methane hydrate Wiley Online Library International Journal for Numerical and Analytical Methods in Geomechanics 44 6 782 802 |
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English |
description |
SUMMARY Recent pore‐scale observations and geomechanical investigations suggest the lack of true cohesion in methane hydrate‐bearing sediments (MHBSs) and propose that their mechanical behavior is governed by kinematic constrictions at pore‐scale. This paper presents a constitutive model for MHBS, which does not rely on physical bonding between hydrate crystals and sediment grains but on the densification effect that pore invasion with hydrate has on the sediment mechanical properties. The Hydrate‐CASM extends the critical state model Clay and Sand Model (CASM) by implementing the subloading surface model and introducing the densification mechanism. The model suggests that the decrease of the sediment available void volume during hydrate formation stiffens its structure and has a similar mechanical effect as the increase of sediment density. In particular, the model attributes stress‐strain changes observed in MHBS to the variations in sediment available void volume with hydrate saturation and its consequent effect on isotropic yield stress and swelling line slope. The model performance is examined against published experimental data from drained triaxial tests performed at different confining stress and with distinct hydrate saturation and morphology. Overall, the simulations capture the influence of hydrate saturation in both the magnitude and trend of the stiffness, shear strength, and volumetric response of synthetic MHBS. The results are validated against those obtained from previous mechanical models for MHBS that examine the same experimental data. The Hydrate‐CASM performs similarly to previous models, but its formulation only requires one hydrate‐related empirical parameter to express changes in the sediment elastic stiffness with hydrate saturation. |
author2 |
Graduate School of the National Oceanography Centre Southampton |
format |
Article in Journal/Newspaper |
author |
De La Fuente, Maria Vaunat, Jean Marín‐Moreno, Héctor |
spellingShingle |
De La Fuente, Maria Vaunat, Jean Marín‐Moreno, Héctor A densification mechanism to model the mechanical effect of methane hydrates in sandy sediments |
author_facet |
De La Fuente, Maria Vaunat, Jean Marín‐Moreno, Héctor |
author_sort |
De La Fuente, Maria |
title |
A densification mechanism to model the mechanical effect of methane hydrates in sandy sediments |
title_short |
A densification mechanism to model the mechanical effect of methane hydrates in sandy sediments |
title_full |
A densification mechanism to model the mechanical effect of methane hydrates in sandy sediments |
title_fullStr |
A densification mechanism to model the mechanical effect of methane hydrates in sandy sediments |
title_full_unstemmed |
A densification mechanism to model the mechanical effect of methane hydrates in sandy sediments |
title_sort |
densification mechanism to model the mechanical effect of methane hydrates in sandy sediments |
publisher |
Wiley |
publishDate |
2020 |
url |
http://dx.doi.org/10.1002/nag.3038 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fnag.3038 https://onlinelibrary.wiley.com/doi/pdf/10.1002/nag.3038 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/nag.3038 |
genre |
Methane hydrate |
genre_facet |
Methane hydrate |
op_source |
International Journal for Numerical and Analytical Methods in Geomechanics volume 44, issue 6, page 782-802 ISSN 0363-9061 1096-9853 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1002/nag.3038 |
container_title |
International Journal for Numerical and Analytical Methods in Geomechanics |
container_volume |
44 |
container_issue |
6 |
container_start_page |
782 |
op_container_end_page |
802 |
_version_ |
1812815779714826240 |