Accumulation mechanism of natural gas hydrate in the Qilian Mountain permafrost, Qinghai, China
Qilian Mountain is the only permafrost area in China where natural gas hydrates have been obtained through scientific drilling. Many studies have been performed on natural gas hydrates in permafrost regions from the perspectives of sedimentology and petroleum geochemistry, especially on reservoir fo...
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ftdoajarticles:oai:doaj.org/article:8139d3fde65b42d2b43eb59af235f3bb 2023-05-15T17:56:38+02:00 Accumulation mechanism of natural gas hydrate in the Qilian Mountain permafrost, Qinghai, China Fugui Zhang Zhibin Yang Yalong Zhou Shunyao Zhang Linsong Yu 2022-09-01T00:00:00Z https://doi.org/10.3389/fenrg.2022.1006421 https://doaj.org/article/8139d3fde65b42d2b43eb59af235f3bb EN eng Frontiers Media S.A. https://www.frontiersin.org/articles/10.3389/fenrg.2022.1006421/full https://doaj.org/toc/2296-598X 2296-598X doi:10.3389/fenrg.2022.1006421 https://doaj.org/article/8139d3fde65b42d2b43eb59af235f3bb Frontiers in Energy Research, Vol 10 (2022) natural gas hydrate source rock accumulation mechanism gas migration Qilian Mountain permafrost General Works A article 2022 ftdoajarticles https://doi.org/10.3389/fenrg.2022.1006421 2022-12-30T21:01:17Z Qilian Mountain is the only permafrost area in China where natural gas hydrates have been obtained through scientific drilling. Many studies have been performed on natural gas hydrates in permafrost regions from the perspectives of sedimentology and petroleum geochemistry, especially on reservoir forming conditions and exploration methods. However, there are still more divergences in its evolutionary process, time, and accumulation mechanism. In this study, a total of 500 core samples were collected in the gas hydrate drilling wells DK-8, DK13-11, and DK12-13 in the Qilian Mountain permafrost. Gas components, carbon isotopes of methane, total organic carbon (TOC), chloroform bitumen “A,” concentrations of kerogen element, and vitrinite reflectance (Ro) are analyzed. The results show that the hydrocarbon source rocks in the Middle Jurassic Muli formation and the Upper Triassic Galedesi formation are good source rocks, with good total organic carbon content and chloroform bitumen “A.” The rocks of Muli formation are at the mature stage of organic matters, and the organic matter types are mainly Ⅱ1 and Ⅱ2 and the peak of generating crude oil with immense petroleum-associated gas. Also, the rocks of the Galedesi formation are in a highly mature stage, producing more gas and offering efficient gas for the natural gas hydrate, and the organic matter types are mainly Ⅲ and Ⅱ1. Laboratory experiments and numerical analysis indicate that the formation of natural gas hydrates in the Qilian Mountain has experienced three phases: gas migration and aggregation in the Late Jurassic to Early Cretaceous, overall uplift in the Middle and Late Miocene to Pliocene, and free gas to natural gas hydrate deposits in the Quaternary. The experimental results show that gas sources, permafrost thickness, and structural conditions played a key role in controlling the occurrence and distribution of gas hydrates. Article in Journal/Newspaper permafrost Directory of Open Access Journals: DOAJ Articles Frontiers in Energy Research 10 |
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natural gas hydrate source rock accumulation mechanism gas migration Qilian Mountain permafrost General Works A |
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natural gas hydrate source rock accumulation mechanism gas migration Qilian Mountain permafrost General Works A Fugui Zhang Zhibin Yang Yalong Zhou Shunyao Zhang Linsong Yu Accumulation mechanism of natural gas hydrate in the Qilian Mountain permafrost, Qinghai, China |
topic_facet |
natural gas hydrate source rock accumulation mechanism gas migration Qilian Mountain permafrost General Works A |
description |
Qilian Mountain is the only permafrost area in China where natural gas hydrates have been obtained through scientific drilling. Many studies have been performed on natural gas hydrates in permafrost regions from the perspectives of sedimentology and petroleum geochemistry, especially on reservoir forming conditions and exploration methods. However, there are still more divergences in its evolutionary process, time, and accumulation mechanism. In this study, a total of 500 core samples were collected in the gas hydrate drilling wells DK-8, DK13-11, and DK12-13 in the Qilian Mountain permafrost. Gas components, carbon isotopes of methane, total organic carbon (TOC), chloroform bitumen “A,” concentrations of kerogen element, and vitrinite reflectance (Ro) are analyzed. The results show that the hydrocarbon source rocks in the Middle Jurassic Muli formation and the Upper Triassic Galedesi formation are good source rocks, with good total organic carbon content and chloroform bitumen “A.” The rocks of Muli formation are at the mature stage of organic matters, and the organic matter types are mainly Ⅱ1 and Ⅱ2 and the peak of generating crude oil with immense petroleum-associated gas. Also, the rocks of the Galedesi formation are in a highly mature stage, producing more gas and offering efficient gas for the natural gas hydrate, and the organic matter types are mainly Ⅲ and Ⅱ1. Laboratory experiments and numerical analysis indicate that the formation of natural gas hydrates in the Qilian Mountain has experienced three phases: gas migration and aggregation in the Late Jurassic to Early Cretaceous, overall uplift in the Middle and Late Miocene to Pliocene, and free gas to natural gas hydrate deposits in the Quaternary. The experimental results show that gas sources, permafrost thickness, and structural conditions played a key role in controlling the occurrence and distribution of gas hydrates. |
format |
Article in Journal/Newspaper |
author |
Fugui Zhang Zhibin Yang Yalong Zhou Shunyao Zhang Linsong Yu |
author_facet |
Fugui Zhang Zhibin Yang Yalong Zhou Shunyao Zhang Linsong Yu |
author_sort |
Fugui Zhang |
title |
Accumulation mechanism of natural gas hydrate in the Qilian Mountain permafrost, Qinghai, China |
title_short |
Accumulation mechanism of natural gas hydrate in the Qilian Mountain permafrost, Qinghai, China |
title_full |
Accumulation mechanism of natural gas hydrate in the Qilian Mountain permafrost, Qinghai, China |
title_fullStr |
Accumulation mechanism of natural gas hydrate in the Qilian Mountain permafrost, Qinghai, China |
title_full_unstemmed |
Accumulation mechanism of natural gas hydrate in the Qilian Mountain permafrost, Qinghai, China |
title_sort |
accumulation mechanism of natural gas hydrate in the qilian mountain permafrost, qinghai, china |
publisher |
Frontiers Media S.A. |
publishDate |
2022 |
url |
https://doi.org/10.3389/fenrg.2022.1006421 https://doaj.org/article/8139d3fde65b42d2b43eb59af235f3bb |
genre |
permafrost |
genre_facet |
permafrost |
op_source |
Frontiers in Energy Research, Vol 10 (2022) |
op_relation |
https://www.frontiersin.org/articles/10.3389/fenrg.2022.1006421/full https://doaj.org/toc/2296-598X 2296-598X doi:10.3389/fenrg.2022.1006421 https://doaj.org/article/8139d3fde65b42d2b43eb59af235f3bb |
op_doi |
https://doi.org/10.3389/fenrg.2022.1006421 |
container_title |
Frontiers in Energy Research |
container_volume |
10 |
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1766164865245773824 |