Effects of gas hydrates dissociation on clays and submarine slope stability
Gas hydrate dissociation is often considered as a precursor or triggering factor for submarine slope failures occurring in relatively deep waters where the bulk of the gas hydrate is found in fine-grained sediments. However, there are actually relatively few studies that focus on the effect of gas h...
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ftoceanrep:oai:oceanrep.geomar.de:39261 2023-05-15T17:12:11+02:00 Effects of gas hydrates dissociation on clays and submarine slope stability Yang, Shaoli Choi, Jung Chan Vanneste, Maarten Kvalstad, Tore 2018 text https://oceanrep.geomar.de/id/eprint/39261/ https://oceanrep.geomar.de/id/eprint/39261/1/Yang.pdf https://doi.org/10.1007/s10064-017-1088-2 en eng Springer https://oceanrep.geomar.de/id/eprint/39261/1/Yang.pdf Yang, S., Choi, J. C., Vanneste, M. and Kvalstad, T. (2018) Effects of gas hydrates dissociation on clays and submarine slope stability. Bulletin of Engineering Geology and the Environment, 77 (3). pp. 941-952. DOI 10.1007/s10064-017-1088-2 <https://doi.org/10.1007/s10064-017-1088-2>. doi:10.1007/s10064-017-1088-2 info:eu-repo/semantics/restrictedAccess Article PeerReviewed 2018 ftoceanrep https://doi.org/10.1007/s10064-017-1088-2 2023-04-07T15:35:04Z Gas hydrate dissociation is often considered as a precursor or triggering factor for submarine slope failures occurring in relatively deep waters where the bulk of the gas hydrate is found in fine-grained sediments. However, there are actually relatively few studies that focus on the effect of gas hydrate dissociation on the behavior of clays, and very few on what physically happens to clay during and after the dissociation process and how gas hydrate dissociation affects the geotechnical properties of clays. In this paper, we illustrate the effects of hydrate dissociation in clays from laboratory strength tests (direct simple shear) combined with visualization including very-high-resolution 3D imaging (computed tomography), using R11 as the hydrate forming fluid in both laponite and Onsøy clay. The test results reveal that the hydrate dissociation creates bubbles in the surrounding clay matrix and around pipe/well models. In addition, we use CO2-saturated water as the pore fluid in soft clay, and test results show that cracks may develop, allowing gas migration to take place after reducing back pressure in an oedometer cell. Direct simple shear tests show that the undrained shear strength decreases by up to ∼15% due to this process. The test results were then implemented in a 2D finite element model to assess the influence of hydrate dissociation on submarine slope stability. We chose a slope segment west of Svalvard—an area where methane gas bubbles escape from the seabed. The gas bubbling in this area is likely due to climate-controlled hydrate-dissociation (warming of bottom water masses). In the finite-element model, we include the change of methane hydrate stability zone (MHSZ) with time as well as the hydrate-dissociation-induced failure zone, which may be a potential leakage pathway. The numerical study indicates that the hydrate dissociation caused by bottom water warming is unlikely to be the main cause generating a leakage pathway or failure plane. However, the hydrate dissociation causing the ... Article in Journal/Newspaper Methane hydrate OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Bulletin of Engineering Geology and the Environment 77 3 941 952 |
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English |
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Gas hydrate dissociation is often considered as a precursor or triggering factor for submarine slope failures occurring in relatively deep waters where the bulk of the gas hydrate is found in fine-grained sediments. However, there are actually relatively few studies that focus on the effect of gas hydrate dissociation on the behavior of clays, and very few on what physically happens to clay during and after the dissociation process and how gas hydrate dissociation affects the geotechnical properties of clays. In this paper, we illustrate the effects of hydrate dissociation in clays from laboratory strength tests (direct simple shear) combined with visualization including very-high-resolution 3D imaging (computed tomography), using R11 as the hydrate forming fluid in both laponite and Onsøy clay. The test results reveal that the hydrate dissociation creates bubbles in the surrounding clay matrix and around pipe/well models. In addition, we use CO2-saturated water as the pore fluid in soft clay, and test results show that cracks may develop, allowing gas migration to take place after reducing back pressure in an oedometer cell. Direct simple shear tests show that the undrained shear strength decreases by up to ∼15% due to this process. The test results were then implemented in a 2D finite element model to assess the influence of hydrate dissociation on submarine slope stability. We chose a slope segment west of Svalvard—an area where methane gas bubbles escape from the seabed. The gas bubbling in this area is likely due to climate-controlled hydrate-dissociation (warming of bottom water masses). In the finite-element model, we include the change of methane hydrate stability zone (MHSZ) with time as well as the hydrate-dissociation-induced failure zone, which may be a potential leakage pathway. The numerical study indicates that the hydrate dissociation caused by bottom water warming is unlikely to be the main cause generating a leakage pathway or failure plane. However, the hydrate dissociation causing the ... |
format |
Article in Journal/Newspaper |
author |
Yang, Shaoli Choi, Jung Chan Vanneste, Maarten Kvalstad, Tore |
spellingShingle |
Yang, Shaoli Choi, Jung Chan Vanneste, Maarten Kvalstad, Tore Effects of gas hydrates dissociation on clays and submarine slope stability |
author_facet |
Yang, Shaoli Choi, Jung Chan Vanneste, Maarten Kvalstad, Tore |
author_sort |
Yang, Shaoli |
title |
Effects of gas hydrates dissociation on clays and submarine slope stability |
title_short |
Effects of gas hydrates dissociation on clays and submarine slope stability |
title_full |
Effects of gas hydrates dissociation on clays and submarine slope stability |
title_fullStr |
Effects of gas hydrates dissociation on clays and submarine slope stability |
title_full_unstemmed |
Effects of gas hydrates dissociation on clays and submarine slope stability |
title_sort |
effects of gas hydrates dissociation on clays and submarine slope stability |
publisher |
Springer |
publishDate |
2018 |
url |
https://oceanrep.geomar.de/id/eprint/39261/ https://oceanrep.geomar.de/id/eprint/39261/1/Yang.pdf https://doi.org/10.1007/s10064-017-1088-2 |
genre |
Methane hydrate |
genre_facet |
Methane hydrate |
op_relation |
https://oceanrep.geomar.de/id/eprint/39261/1/Yang.pdf Yang, S., Choi, J. C., Vanneste, M. and Kvalstad, T. (2018) Effects of gas hydrates dissociation on clays and submarine slope stability. Bulletin of Engineering Geology and the Environment, 77 (3). pp. 941-952. DOI 10.1007/s10064-017-1088-2 <https://doi.org/10.1007/s10064-017-1088-2>. doi:10.1007/s10064-017-1088-2 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1007/s10064-017-1088-2 |
container_title |
Bulletin of Engineering Geology and the Environment |
container_volume |
77 |
container_issue |
3 |
container_start_page |
941 |
op_container_end_page |
952 |
_version_ |
1766068981092843520 |