Issue |
E3S Web of Conf.
Volume 382, 2023
8th International Conference on Unsaturated Soils (UNSAT 2023)
|
|
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Article Number | 18001 | |
Number of page(s) | 6 | |
Section | Multi Phase Media and Multi Physical Coupling - Part I | |
DOI | https://doi.org/10.1051/e3sconf/202338218001 | |
Published online | 24 April 2023 |
Gas production behaviour of gas hydrate–bearing clayey-sand during depressurization: novel in-flight centrifuge modelling
1 Geotechnical Centrifuge Facility, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR
2 Department of Civil and Environmental Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR
* Corresponding author: sina@ust.hk
Gas hydrate-bearing sediments (GHBS) are vastly distributed around the globe. While gas production attempts are made through GHBS, long-term production remains a challenge due to complex inter-related mechanisms involved. Better understating of long-term responses requires sound physical modelling conducted under controlled conditions. A novel centrifuge energy harvesting chamber (CEHC) at the HKUST centrifuge facility is used in this study. This is the first chamber that can operate at elevated gravities with the capability of sustaining the thermodynamically favourable conditions for gas hydrate formation, sustaining a continuous inflow of high-pressure water at the boundaries during dissociation, and an in-flight control of wellbore pressure and surcharge loading. Centrifuge modelling can recreate the insitu stress gradient in a relatively small model and expedite conduction and convection processes involved during dissociation. Consequently, long-term in-situ mechanisms can be evaluated with a small model and short time. A test was conducted at 40g to evaluate the temperature-pressure response as well as gas production behaviour of hydrate-bearing clayey-sand during depressurization. The results suggests that the gas flow rate is governed by the initial available latent heat as well as the conduction and convection heat through the surrounding sediments. However, as the depressurization progresses, the gas production rate is governed by the competing effects of hydrate dissociation and re-formation which both evolves the permeability of the sediment. Details of the experiment and test results are reported in this paper.
© The Authors, published by EDP Sciences, 2023
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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