Shallow gas hydrates off southwest Taiwan and their mechanisms

Huang, Yushu; Hsu, Shu Kun; Su, Chih-Chieh; Lin, A. T.; Yu, Pai‐Sen; Babonneau, Nathalie; Ratzov, Gueorgui; Lallemand, Serge; Huang, Pi Chuen; Lin, Shih Chang; Lin, Jing Yi; Wei, Kuo-Yen; Chang, Yuan‐Pin; Yu, Neng Ti; Tsai, Chia-Wei

doi:10.1007/s11001-021-09429-x

Cited by 7 publications

(3 citation statements)

References 37 publications

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“…43−47 Gas hydrate samples have been successfully collected at two sites off southwest Taiwan in 2018, where one occurred a structural unconformity at ∼5.5 m below the seafloor, and the other distributed a gasrelated pockmark structure near the seafloor. 48 The southern part of the South China Sea, especially in the Nansha Trough, Zengmu Basin, and Palawan Basin, has good formation conditions for gas hydrates. 49 The Nansha Trough is a NE-SW trending deep sea trough with water depths of 2800−2900 m, and contains abundant oil and gas resources.…”

Section: Occurrencesmentioning

confidence: 99%

“…The South China Sea Plate subducted below the Manila Trench and collided to form an imbricate accretionary wedge represented by the Hengchun Ridge . BSRs with an area of 2 × 10 4 km 2 were widely distributed over both active and passive continental margins in the offshore Taiwan subduction and accretionary wedge, indicative of the existence of natural gas hydrates. − Gas hydrate samples have been successfully collected at two sites off southwest Taiwan in 2018, where one occurred a structural unconformity at ∼5.5 m below the seafloor, and the other distributed a gas-related pockmark structure near the seafloor …”

Section: Occurrencesmentioning

confidence: 99%

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A Review of the Resource and Test Production of Natural Gas Hydrates in China

et al. 2021

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China has been attaching great importance to research on natural gas hydrate resources. Since the mid-1990s, China has experienced three stages of resource prediction, investigation, and test production. Until now, five hydrate accumulations have been discovered by drilling and sampling in the Shenhu, Dongsha, Qiongdongnan Basins, and offshore Taiwan of the South China Sea and in the Muli area of Qilian Mountain, and seven hydrates have been inferred by various indicators, including geology, geophysics and geochemistry in the South China Sea, the East China Sea, and the Qinghai–Tibet Plateau. According to the hydrate stability zone, the natural gas hydrate resources in the South China Sea are estimated to be 64.6 × 1012 m3, those in the East China Sea are ∼28.5 × 1012 m3, and those in the terrestrial permafrost are ∼38 × 1012 m3. The total amount of the natural gas hydrates in China reaches up to 131.1 × 1012 m3, which is twice the amount of China’s conventional natural gas resources. China has successfully conducted the five field test production of gas hydrates in the Muli permafrost region of Qilian Mountain and in Shenhu area of the South China Sea since 2011, in particular first using horizontal well technologies to exploit hydrates that occurred in the fine-grained reservoirs. It is expected that commercial production from the hydrate reservoir will come true in the 2030s.

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Section: Occurrencesmentioning

confidence: 99%

Section: Occurrencesmentioning

confidence: 99%

A Review of the Resource and Test Production of Natural Gas Hydrates in China

et al. 2021

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“…A gas hydrate (GH) is an ice-like compound containing abundant methane gas formed only under low-temperature and high-pressure conditions 1 – 4 . Natural GHs exist on or beneath the seafloor 5 – 9 and in permafrost areas 10 . As GHs are rich in methane, their dissociation causes its release into the ocean and atmosphere, aggravating global warming 11 – 13 .…”

Section: Introductionmentioning

confidence: 99%

Electrical resistivity tomography combined with seismic data estimates heterogeneous distribution of near-seafloor concentrated gas hydrates within gas chimneys

Ishizu,

Oda,

Goto

et al. 2024

Sci Rep

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Near-seafloor concentrated gas hydrates (GHs) containing large amounts of methane have been identified at various gas chimney sites. Although understanding the spatial distribution of GHs is fundamental for assessing their dissociation impact on aggravating global warming and resource potential, the spatial distribution of GHs within gas chimneys remains unclear. Here, we estimate the subseafloor distribution of GHs at a gas chimney site in the Japan Sea using marine electrical resistivity tomography data. The resulting two-dimensional subseafloor resistivity structure shows high anomalies (10–100 Ωm) within seismically inferred gas chimneys. As the resistivity anomalies are aligned with high amplitude seismic reflections and core positions recovering GHs, we interpret the resistivity anomalies are near-seafloor concentrated GH deposits. We also detect various distribution patterns of the high resistivity anomalies including 100-m wide and 40-m thick anomaly near the seafloor and 500-m wide anomaly buried 50 m below the seafloor, suggesting that GHs are heterogeneously distributed. Therefore, considering such heterogeneous GH distribution within gas chimneys is critical for in-depth assessments of GH environmental impacts and energy resources.

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An integrated, non-destructive method for evaluating core quality from R/V Legend’s giant piston coring system (LGD-GPC)

Yu,

Chen

2023

Terr Atmos Ocean Sci

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Despite technological advances, some core disturbances due to piston coring process still occur and can be extremely difficult to identify characteristics of sedimentary structures during qualitative visual core description and core lithologies. Few quantitative methods have offered plausible ways to define the exact magnitude of the distorted sedimentary structures in imperfect sedimentary records in the context of overly limited sedimentary records. In this study, an investigation was conducted on the Kaoping slope offshore southwestern Taiwan, a region known for its high sedimentation rate (> 0.9 g/cm2/year), using both the LGD-GPC (giant piston corer) and giant gravity corer techniques. To examine how GPC procedures have shaped the retrieval of sedimentary sequences and affected core quality, we apply well-developed, non-destructive analyses, including physical property measurements, visible color reflectance and digital core images with quantitative curvature index (CI), to recovered sediments. Cores at 22° 23′N, 120° 13′E were as the basis for non-destructive measurement comparison. Evidence from digital core imaging and the CI calculation further supports the mechanism of piston suction. We suggest that shear deformation of sediment against the core barrel would be the prominent factor that govern the observed core disturbances in LGD-GPC cores. Meanwhile, excessive pulling forcing from a modified TORI piston and a slowly lift speed during LGD-GPC coring process may further aggravate core disturbances at the revisited site. The sedimentary length of core LGD-T43-B-PC is overestimated by more than 200%. We further demonstrate that an integration of the CI and color reflectance is an effective way to evaluate the transformation and distorted sedimentary sequences.

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Shallow gas hydrates off southwest Taiwan and their mechanisms

Cited by 7 publications

References 37 publications

A Review of the Resource and Test Production of Natural Gas Hydrates in China

A Review of the Resource and Test Production of Natural Gas Hydrates in China

Electrical resistivity tomography combined with seismic data estimates heterogeneous distribution of near-seafloor concentrated gas hydrates within gas chimneys

An integrated, non-destructive method for evaluating core quality from R/V Legend’s giant piston coring system (LGD-GPC)

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