date: 2022-07-08T09:46:39Z
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pdf:docinfo:title: Numerical Simulation of Coastal Sub-Permafrost Gas Hydrate Formation in the Mackenzie Delta, Canadian Arctic
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Keywords: gas hydrate; permafrost; methane; faults; climate change; Mallik; numerical simulations
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subject: The Mackenzie Delta (MD) is a permafrost-bearing region along the coasts of the Canadian Arctic which exhibits high sub-permafrost gas hydrate (GH) reserves. The GH occurring at the Mallik site in the MD is dominated by thermogenic methane (CH4), which migrated from deep conventional hydrocarbon reservoirs, very likely through the present fault systems. Therefore, it is assumed that fluid flow transports dissolved CH4 upward and out of the deeper overpressurized reservoirs via the existing polygonal fault system and then forms the GH accumulations in the Kugmallit?Mackenzie Bay Sequences. We investigate the feasibility of this mechanism with a thermo?hydraulic?chemical numerical model, representing a cross section of the Mallik site. We present the first simulations that consider permafrost formation and thawing, as well as the formation of GH accumulations sourced from the upward migrating CH4-rich formation fluid. The simulation results show that temperature distribution, as well as the thickness and base of the ice-bearing permafrost are consistent with corresponding field observations. The primary driver for the spatial GH distribution is the permeability of the host sediments. Thus, the hypothesis on GH formation by dissolved CH4 originating from deeper geological reservoirs is successfully validated. Furthermore, our results demonstrate that the permafrost has been substantially heated to 0.8?1.3 °C, triggered by the global temperature increase of about 0.44 °C and further enhanced by the Arctic Amplification effect at the Mallik site from the early 1970s to the mid-2000s.
dc:creator: Zhen Li, Erik Spangenberg, Judith M. Schicks and Thomas Kempka
dcterms:created: 2022-07-08T09:37:06Z
Last-Modified: 2022-07-08T09:46:39Z
dcterms:modified: 2022-07-08T09:46:39Z
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title: Numerical Simulation of Coastal Sub-Permafrost Gas Hydrate Formation in the Mackenzie Delta, Canadian Arctic
Last-Save-Date: 2022-07-08T09:46:39Z
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pdf:docinfo:keywords: gas hydrate; permafrost; methane; faults; climate change; Mallik; numerical simulations
pdf:docinfo:modified: 2022-07-08T09:46:39Z
meta:save-date: 2022-07-08T09:46:39Z
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dc:title: Numerical Simulation of Coastal Sub-Permafrost Gas Hydrate Formation in the Mackenzie Delta, Canadian Arctic
modified: 2022-07-08T09:46:39Z
cp:subject: The Mackenzie Delta (MD) is a permafrost-bearing region along the coasts of the Canadian Arctic which exhibits high sub-permafrost gas hydrate (GH) reserves. The GH occurring at the Mallik site in the MD is dominated by thermogenic methane (CH4), which migrated from deep conventional hydrocarbon reservoirs, very likely through the present fault systems. Therefore, it is assumed that fluid flow transports dissolved CH4 upward and out of the deeper overpressurized reservoirs via the existing polygonal fault system and then forms the GH accumulations in the Kugmallit?Mackenzie Bay Sequences. We investigate the feasibility of this mechanism with a thermo?hydraulic?chemical numerical model, representing a cross section of the Mallik site. We present the first simulations that consider permafrost formation and thawing, as well as the formation of GH accumulations sourced from the upward migrating CH4-rich formation fluid. The simulation results show that temperature distribution, as well as the thickness and base of the ice-bearing permafrost are consistent with corresponding field observations. The primary driver for the spatial GH distribution is the permeability of the host sediments. Thus, the hypothesis on GH formation by dissolved CH4 originating from deeper geological reservoirs is successfully validated. Furthermore, our results demonstrate that the permafrost has been substantially heated to 0.8?1.3 °C, triggered by the global temperature increase of about 0.44 °C and further enhanced by the Arctic Amplification effect at the Mallik site from the early 1970s to the mid-2000s.
pdf:docinfo:subject: The Mackenzie Delta (MD) is a permafrost-bearing region along the coasts of the Canadian Arctic which exhibits high sub-permafrost gas hydrate (GH) reserves. The GH occurring at the Mallik site in the MD is dominated by thermogenic methane (CH4), which migrated from deep conventional hydrocarbon reservoirs, very likely through the present fault systems. Therefore, it is assumed that fluid flow transports dissolved CH4 upward and out of the deeper overpressurized reservoirs via the existing polygonal fault system and then forms the GH accumulations in the Kugmallit?Mackenzie Bay Sequences. We investigate the feasibility of this mechanism with a thermo?hydraulic?chemical numerical model, representing a cross section of the Mallik site. We present the first simulations that consider permafrost formation and thawing, as well as the formation of GH accumulations sourced from the upward migrating CH4-rich formation fluid. The simulation results show that temperature distribution, as well as the thickness and base of the ice-bearing permafrost are consistent with corresponding field observations. The primary driver for the spatial GH distribution is the permeability of the host sediments. Thus, the hypothesis on GH formation by dissolved CH4 originating from deeper geological reservoirs is successfully validated. Furthermore, our results demonstrate that the permafrost has been substantially heated to 0.8?1.3 °C, triggered by the global temperature increase of about 0.44 °C and further enhanced by the Arctic Amplification effect at the Mallik site from the early 1970s to the mid-2000s.
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pdf:docinfo:creator: Zhen Li, Erik Spangenberg, Judith M. Schicks and Thomas Kempka
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creator: Zhen Li, Erik Spangenberg, Judith M. Schicks and Thomas Kempka
meta:author: Zhen Li, Erik Spangenberg, Judith M. Schicks and Thomas Kempka
dc:subject: gas hydrate; permafrost; methane; faults; climate change; Mallik; numerical simulations
meta:creation-date: 2022-07-08T09:37:06Z
created: Fri Jul 08 11:37:06 CEST 2022
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meta:keyword: gas hydrate; permafrost; methane; faults; climate change; Mallik; numerical simulations
Author: Zhen Li, Erik Spangenberg, Judith M. Schicks and Thomas Kempka
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