A Preliminary Study of the Gas Hydrate Stability Zone in the South China Sea

Chunshuang, Jin; Wang, Jing

doi:10.1111/j.1755-6724.2002.tb00095.x

Cited by 23 publications

(5 citation statements)

References 14 publications

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“…The marine sediments [24][25][26] cover a wide range of water depth, from about 470 m to 3000 m corresponding to the pressure from 4.7 MPa to 30 MPa and the range of temperature from 2.2 to 10 • C [27]. Microbial metabolism was extremely slow if the temperature below 4 • C. Previous experiment studies showed that when the temperature was higher than 4 • C, the metabolism of anaerobic microbes accelerated, and authigenic minerals are easier to form [19].…”

Section: Methodsmentioning

confidence: 99%

Laboratory Experimental Study on the Formation of Authigenic Carbonates Induced by Microbes in Marine Sediments

Wei

Shang

et al. 2021

JMSE

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Authigenic carbonates are widely distributed in marine sediments, microbes, and anaerobic oxidation of methane (AOM) play a key role in their formation. The authigenic carbonates in marine sediments have been affected by weathering and diagenesis for a long time, it is difficult to understand their formation process by analyzing the samples collected in situ. A pore water environment with 10 °C, 6 MPa in the marine sediments was built in a bioreactor to study the stages and characteristics of authigenic carbonates formation induced by microbes. In experiments, FeCO3 is formed preferentially, and then FeCO3-MgCO3 complete isomorphous series and a small part of CaCO3 isomorphous mixture are formed. According to this, it is proposed that the formation of authigenic carbonates performed by AOM and related microbes needs to undergo three stages: the rise of alkalinity, the preferential formation of a carbonate mineral, and the formation of carbonate isomorphous series. This work provides experimental experience and reference basis for further understanding the formation mechanism of authigenic carbonates in marine sediments.

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Section: Methodsmentioning

confidence: 99%

Laboratory Experimental Study on the Formation of Authigenic Carbonates Induced by Microbes in Marine Sediments

Wei

Shang

et al. 2021

JMSE

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“…Ds is the diffusion coefficient of the whole sediment package after curve correction, C is the concentration of components in pore water, x is depth, and dc/dx is the vertical concentration gradient. This study assumed that the average pH value of sediment for all research stations was 7.5, and the bottom water temperature was uniformly set as 5 °C (refer to (Jin and Wang, 2010). The diffusion coefficients D SW (m 2 s -1 ) of pore water components (SO 4 2-, CH 4 , Ca 2+ , DIC) at the relevant temperature and salinity were taken from Schulz (2006) and corrected for the set temperature and salinity.…”

Section: Numerical Modelingmentioning

confidence: 99%

The effects of organic matter and anaerobic oxidation of methane on the microbial sulfate reduction in cold seeps

Sun

et al. 2023

Front. Mar. Sci.

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Cold seep sediments are dominated by intensive microbial sulfate reduction coupled to anaerobic oxidation of methane. However, the contribution proportion between this process and the role of organic matter has remained enigmatic. Here, pore water data combined with PROFILE model, fluxes of sulfate and methane concentration calculated from Fick's first law, and δ34SSO4 and δ18OSO4 of pore water sulfate were studied to reconstruct co-occurring microbial organoclastic sulfate reduction and anaerobic oxidation of methane coupled with sulfate reduction in methane seep sediments collected from South China Sea. The sulfate concentration profiles of C9 and C14 in Qiongdongnan Basin generally show quasilinear depletion with depth. Reaction-transport modeling provided close fits to concentration data. δ18OSO4 and δ34SSO4 increase fastest with sediment depth above 400 cmbsf and slowest below that depth. The values of methane flux are always lower than those of total sulfate reduction of sulfate diffusive flux at GC-10, GC-9, GC-11 and HD319 sites in Taixinan Basin. Besides, positions of sulfate methane transition zone in all study sites are approximately ~400 to 800 centimeters below seafloor. These results showed that microbial sulfate reduction in sediments is mainly controlled by intense anaerobic oxidation of methane, but there is a certain relationship with organic matter metabolism process. This emphasizes that traditional redox order of bacterial respiration is highly simplified, where, in sediments such as these seeps, all of these microbial sulfate reduction processes can occur together with complex couplings between them.

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“…Now, these gas sources are still in the major gas generating and accumulation stages. Rapid sedimentation and strong thermotectonic movements since the Neogene not only accelerate the generation of natural gas in this region, but also promote coexistence of hydrocarbon gas, N2 and COZ formed in different stages (from a shallow diagenetic stage: R,,<0.50% to a para-metamorphic stage at deptb: R 2 3 8 ) (Jin and Wang, 2002). This resulted in the reservoiring history of complex composition and multi-phase gas migration and accumulation in the Yinggehai Basin, and also resulted in the evident difference in composition and properties of the natural gas in different gas-bearing formations in the same gas field ( Fig.…”

Section: Basinmentioning

confidence: 99%

Post‐Neogene Structural Evolution: An Important Geological Stage in the Formation of Gas Reservoirs in China

Tingbin¹

2004

Acta Geologica Sinica (Eng)

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Tectonic movements since the Neogene have been the major developmental and evolutional stages of the latest global crustal deformation and orogenic movements. China is located in a triangular area bounded by the Indian landmass, the West Siberian landmass and the Pacific Plate, characterized by relatively active tectonic movements since the Neogene, and in this region, natural gas would have been very easy to dissipate, or difficult to preserve. Therefore, the characteristics of post‐Neogene tectonic movements offer important geological factors in researching the formation and preservation of gas reservoirs in China. Summarizing the reservoiring history of gas fields in China, although there are some differences between various basins, they are all affected by the tectonic movements since the Neogene. These movements have certainly caused destruction to the reservoiring and distribution of natural gas in China, which has resulted in a certain dissipation of natural gas in some basins. As a whole, however, they have mainly promoted the reservoiring and accumulation of natural gas: (1) a series of China‐type foreland basins have been formed between basins and ridges in western China, which provide favorable conditions for the formation of large and medium gas fields, as well as controlling the finalization of gas reservoirs in the basins; (2) rows and belts of anticlines have been formed in the Sichuan Basin in central China, which have been the major stages of the formation and finalization of gas reservoirs in that basin; the integral and quick rising and lifting, and a further west‐dipping in the Ordos Basin have resulted in a further accumulation of natural gas in gas fields from Jingbian to Uxin; (3) in eastern China, the Bohai movement in the late Pliocene has provided favorable geological conditions for lately‐formed gas reservoirs in the Bohai Sea area mainly composed of the Bozhong depression; and it also resulted in secondary hydrocarbon generation and formation of secondary gas reservoirs in other basins, as well as the formation of many carbon dioxide gas fields of inorganic origin; (4) in the offshore area, it promoted not only the formation of gas reservoirs of organic origin, but also the formation of inorganic origin non‐hydrocarbon gas reservoirs, as well as the organic and inorganic natural gas of mixed origin, which resulted in the relatively complicated characteristics of gas reservoirs in the area. In short, tectonic movements activated since the Neogene resulted in a reservoiring model mainly characterized by late and superlate hydrocarbon generation and accumulation. These events provide an important geological stage that should not be neglected when studying the formation of gas reservoirs in China.

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A Preliminary Study of the Gas Hydrate Stability Zone in the South China Sea

Cited by 23 publications

References 14 publications

Laboratory Experimental Study on the Formation of Authigenic Carbonates Induced by Microbes in Marine Sediments

Laboratory Experimental Study on the Formation of Authigenic Carbonates Induced by Microbes in Marine Sediments

The effects of organic matter and anaerobic oxidation of methane on the microbial sulfate reduction in cold seeps

Post‐Neogene Structural Evolution: An Important Geological Stage in the Formation of Gas Reservoirs in China

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