Deposition processes of gas hydrate-bearing sediments in the inter-canyon area of Shenhu Area in the northern South China Sea

Lin, Zhixuan; Zhuo, Haiteng; Su, Pibo; Liang, Jin; Wang, Feifei; Yang, Chengzhi; Luo, Kunwen

doi:10.1007/s00343-022-2084-3

Cited by 6 publications

(5 citation statements)

References 52 publications

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“…Gas hydrate and cold seep were widely observed in the northern and southern SCS margin, whose distribution and saturation are proved to be closely related with geothermal situation and coarse Vol. 41 sedimentation (Jin et al, 2023;Lin et al, 2023;Zhao et al, 2023). Cao et al (2023) investigated Mg/Ca, Ba/Ca, and S/Ca profiles of a bivalve shell fossil for bivalve shells from the Haima cold seep of Qiongdongnan Basin.…”

Section: The Geological Framework and Topographic Variations Of The Scsmentioning

confidence: 99%

Geological environment in the South China Sea

2023

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The South China Sea (SCS), situated in southern China, at the junction of the Pacific Plate, the Eurasian Plate, and the Indian Ocean Plate, is a northeast-southwest trending semi-enclosed sea. It spans an area of approximately 3.5 million square kilometers and has an average water depth of about 1 200 m, its deepest point reaching 5 559 m. In 2021, a scientific expedition (called as U1 voyage) in the South China Sea was organized by the Innovation Research Team of Guangdong Special Key Program from March to April, this marks the first comprehensive scientific research voyage to the southern Uboundary corridor. Consisting of a total of 30 papers, this special issue is to share a portion of the research findings from this scientific expedition U1 voyage, covering six aspects: 1) characteristics of the marine ecosystem in the SCS and its response to marine dynamic processes; 2) multi-scale marine dynamic processes, sea-air interactions, and forecasting techniques in the SCS; 3) geomorphology and geological structure; 4) sedimentary processes and resource potential in the SCS; 5) geostrategy, rights and interests maintenance and strategic countermeasures in the SCS; 6) marine scientific instruments. By integrating the scientific research with the study of history, jurisprudence and international strategies, this issue presents new insights into the formation history and scope evolution of the SCS, and it also seeks to establish a new scientific framework based on the marine governance and development of the SCS.

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Section: The Geological Framework and Topographic Variations Of The Scsmentioning

confidence: 99%

Geological environment in the South China Sea

2023

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“…Gas hydrate reservoirs can be identified by analyzing the logging characteristics of the sedimentary strata. The distribution of the gas hydrates in the sedimentary layer can be estimated effectively using the multi-means exploration technology of geophysical logging (Lu et al, 2008;Liang et al, 2010;Liang et al, 2017a). The gas hydrate reservoirs with different types or different saturations have different logging responses: the resistivity and acoustic velocity in gas hydrate reservoirs are significantly higher than those of the surrounding sediments, while the neutron porosity, density, and natural gamma are slightly lower, and the acoustic velocity, density, and neutron porosity are significantly lower (Wang et al, 2003;Mo et al, 2008;Liang et al, 2017b).…”

Section: Logging Characteristics Of Gas Hydratesmentioning

confidence: 99%

“…The distribution of the gas hydrates in the sedimentary layer can be estimated effectively using the multi-means exploration technology of geophysical logging (Lu et al, 2008;Liang et al, 2010;Liang et al, 2017a). The gas hydrate reservoirs with different types or different saturations have different logging responses: the resistivity and acoustic velocity in gas hydrate reservoirs are significantly higher than those of the surrounding sediments, while the neutron porosity, density, and natural gamma are slightly lower, and the acoustic velocity, density, and neutron porosity are significantly lower (Wang et al, 2003;Mo et al, 2008;Liang et al, 2017b). Site W17 is located in the southeastern part of the study area, at the bottom of the northern continental slope of the South China Sea, with a water depth of 1249 m and a maximum well depth of 319 m. The logging curve for site W17 shows that the abnormal characteristics of "two highs and three lows" values of the logging curves are obvious in the 1460-1522 m section (Figure 6).…”

Section: Logging Characteristics Of Gas Hydratesmentioning

confidence: 99%

“…At present, the geophysical characteristics of hydrate-bearing sediments has been studied by many experts and scholars (Liang et al, 2013;Yu et al, 2014). Compared with the surrounding unconsolidated sediments, pure hydrates are considered to have the physical properties of a high acoustic velocity and resistivity and low density.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, when the sedimentary strata are inclined on the continental slope or in the shallow seabed, the BSR on the seismic profile usually obliquely crosses the sedimentary strata (Paull et al, 1991;Kvenvolden, 1993;Liang et al, 2016). On the logging curve, gas hydrate-bearing strata usually has obvious high resistivity and high acoustic velocity (Hyndman and Davis, 1992;Liang et al, 2013). In addition, since gas hydrates are usually formed in sedimentary layers with relatively large pores, the neutron porosity is slightly higher and the spontaneous potential value is relatively small (Kawasaki et al, 2011;Boswell et al, 2012;Lee and Collett, 2012).…”

Section: Introductionmentioning

confidence: 99%

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Drilling Cores and Geophysical Characteristics of Gas Hydrate-Bearing Sediments in the Production Test Region in the Shenhu sea, South China sea

et al. 2022

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Gas hydrate production testing was conducted in 2017 in the Shenhu Area in the northern part of the South China Sea, and unprecedented success was achieved. In order to obtain gas production and physical properties of gas hydrate reservoirs in the study area and determine the location of test production wells, the seismic and logging data and drilling cores were analyzed in detail, the physical characteristics of the sediments, faults, gas components, and reservoir were studied. The results show that 1) the gas hydrates are diffusion type, with reservoirs dominated by clayey silt sediments, and the gas hydrate-bearing layers are characterized by soup-like, porridge-like, cavity, and vein structures; 2) the resistivity and acoustic velocity of gas hydrate formation are significantly higher than those of the surrounding sediments, while the neutron porosity, density, and natural gamma are slightly lower; the Bottom Simulating Reflectors (BSRs) in seismic profiles exhibit the exist of gas hydrates; 3) gas chimneys and faults are well-developed beneath the BSRs, and hydrocarbon gases can easily migrate into the gas hydrate reservoirs in areas with stable temperature and pressure conditions; 4) the gas hydrate saturation is high, the highest saturation in site W17 was up to 76%, with an average of 33%; while the highest saturation in site W19 was up to 68%, with an average of 31%. The gas source is considered as mixed gas of thermogenic gas and microbial gas. By comparing the core samples and geophysical characteristics of sites W17 and W19 in the study area and calculating the thickness, distribution area, and saturation of the hydrate deposition layer, it was found that site W17 is characterized by a thick layer, large area, high saturation, and good sealing, and thus, site W17 was established as the test production site. The development of gas chimney and faults provides pathways for the upward migration of deep gas, and the gas migrates to gas hydrate stable zone in forms of diffusion, water soluble and free state, forming high saturation of diffusion gas hydrates.

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