Modeling on Gas Hydrate Formation Conditions in the Qinghai-Tibet Plateau Permafrost
TL;DR: Based on the field-investigated gas geochemistry, the modeling of gas hydrate formation conditions in the Qinghai-Tibet plateau permafrost (QTPP) was conducted in this article.
Abstract: Based on the field-investigated gas geochemistry, the modeling of gas hydrate formation conditions is conducted in the Qinghai-Tibet plateau permafrost (QTPP) in combination with predecessors' data such as the permafrost ground temperature (T0), the thermal gradient within the frozen layer (G1) and the thermal gradient below the frozen layer (G2). The modeled results show that the permafrost characteristics generally meet the requirements for gas hydrate formation conditions in the study area. Gas composition, temperaturerelated permafrost parameters (e.g. T0,G1,G2) are the most important factors affecting gas hydrate formation conditions in the study area, whose spatial variations may cause the heterogeneity of gas hydrate occurrences. The most probable gas composition to form gas hydrate is the hybrid of methane and weight hydrocarbon gases (ethane and propane). In the predicted gas hydrate locations, the minimal upper depth of gas hydrate occurrence is less than one hundred meters and the maximum lower depth can reach one thousand meters with the thickness up to several hundred meters. Compared with Canadian Mallik gas hydrate field, the QTPP is favorable for gas hydrate formation in aspects of G1, G2 and gas composition, except for relatively thin permafrost, still suggesting great gas hydrate potentials.
Citations
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TL;DR: In this paper, the authors used a single vertical well by depressurization method to simulate the gas production potential of the gas hydrate deposits in the Qilian Mountain permafrost.
114 citations
TL;DR: In this article, four scientific experimental wells were drilled in the Qilian Mountain permafrost of Qinghai Province, China, in 2008 and 2009 to evaluate the type of clathrates recovered from these sites, including structures containing large and small cages of hydrocarbon gases.
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Cites result from "Modeling on Gas Hydrate Formation C..."
...Since the preliminary results were possibly indicative of gas hydrate potentials in the Qinghai-Tibet railway permafrost (Lu et al., 2009), China Geological Survey formally initiated a project for “investigation on gas hydrate prospects within permafrost areas around China from 2004 to 2006”....
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TL;DR: In this paper, the authors employed the huff and puff method using a single horizontal well in the middle of the Hydrate-Bearing Layer (HBL) to numerically investigate the gas production potential from hydrates at the DK-3 drilling site of the Qilian Mountain permafrost, which is located in the north of the Qinghai-Tibet plateau.
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TL;DR: Zhang et al. as mentioned in this paper investigated the commercial viability of gas hydrate deposits in the Qinghai-Tibet Plateau permafrost during the Scientific Drilling Project of Gas Hydrate.
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TL;DR: In this article, the characteristics of occurrence, structure and gas composition of marine gas hydrate from the South China Sea (SCS) were compared with those from Qilian Mountain permafrost (QMP) in 2009 and 2013.
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References
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TL;DR: In this article, the concentration of gas hydrate at the Mallik 2L-38 research site using P- and S-wave velocities obtained from well logging and vertical seismic profiles (VSP).
68 citations
"Modeling on Gas Hydrate Formation C..." refers background in this paper
...21% from VSP-based calculations respectively and 60, 50% from well-log calculations respectively ([45])....
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TL;DR: In this paper, the aromatic hydrocarbon biomarker distributions of thirty Oligocene sediment samples with different lithology (lignite, clay and sand) from the JAPEX/JNOC/GSC et al. Mallik 5L-38 Gas Hydrate Production Research Well were analyzed using gas chromatography-mass spectrometry (GC-MS).
63 citations
DOI•
06 Aug 2010
TL;DR: In this paper, the results from a geological and geophysical investigation of the gas hydrate reservoir system of the Shenhu Area, located in the north slope of South China Sea, were presented.
Abstract: Gas hydrate is a type of ice-like solid substance formed by the combination of certain low-molecular-weight gases such as methane, ethane, and carbon dioxide with water. Gas hydrate primarily occurs naturally in sediments beneath the permafrost and the sediments of the continental slope with the water depth greater than 300 m. Marine gas hydrate geological systems are important because they may be sufficiently concentrated in certain locations to be an economically viable fossil fuel resource. However, gas hydrates can cause geo-hazards through large-scale slope destabilization and can release methane, a potential greenhouse gas, into the environment. This paper discussed the hydrate drilling results from a geological and geophysical investigation of the gas hydrate reservoir system of the Shenhu Area, located in the north slope of South China Sea. The paper identified the basic formation conditions, and discussed the pore-water geochemical features of shallow sediments and their inflected gas sources, gas hydrate distribution and seismic characteristics. It was concluded that the gas hydrate was heterogeneously distributed in space, and mainly distributed in certain ranges above the bottom of the gas hydrate stability zone. It was also concluded that methane gas that formed hydrate was likely from in-situ micro-biogenic methane. Last, it was found that distributed and in-situ micro-biogenic methane resulted in low methane flux, and formed the distributed pattern of gas hydrate system with the features of differential distribution and saturation. 34 refs., 2 tabs., 3 figs.
52 citations
TL;DR: In this paper, eight monitoring sites are set along the Qinghai-Xizang Highway (QXH) to investigate the characteristics and process of interaction between permafrost and highway, including the upper and down boundaries of active layer under natural surface, seasonally freezing-thawing depth under asphalt pavement, permafeur table temperature and roadbed stability.
Abstract: Eight monitoring sites are set along the Qinghai-Xizang Highway (QXH) to investigate the characteristics and process of interaction between permafrost and highway, including the upper and down boundaries of active layer under natural surface, seasonally freezing-thawing depth under asphalt pavement, permafrost table temperature and roadbed stability. The investigation results show that the changes of active layer thickness and permafrost table temperature under asphalt pavement are greater than these under natural surface due to the absorbing heat action and less evaporation of asphalt pavement, as a result, the engineering geological problems such as thaw settlement and frost heave present frequently along QXH line and produce the adverse impact on roadbed stability.
45 citations
"Modeling on Gas Hydrate Formation C..." refers background in this paper
...Calculated by the empirical relation of D to latitude and altitude, D amounts up to 700 m([34])....
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TL;DR: Based on the thickness of frozen layer and thermal gradient in Qinghai-Tibet Plateau permafrost, the occurrence and distribution of gas hydrate in the low-middle latitude and high altitude permaculture region was predicted by using the thermodynamic method of natural gas hydrates stable temperature and pressure.
Abstract: Permafrost is one of major geological environments for gas hydrate occurrences. Mean altitude is over 4000m and the permafrost area is about 1.4 x 10(6)km(2) in Qinghai-Tibet Plateau. Based on the thickness of frozen layer and thermal gradient in Qinghai-Tibet Plateau permafrost, the occurrence and distribution of gas hydrate in the low-middle latitude and high altitude permafrost is predicted by using the thermodynamic method of natural gas hydrate stable temperature and pressure. The thermodynamic phase equilibrium of thermogenic and biogenic gas hydrate imply that gas hydrate is buried in depth from similar to 27 to similar to 2070m, and the resource potential of natural gases caged in hydrates are estimated as about 1.2 x 10(11) to 2.4 x 10(14)m(3) in Qinghai-Tibet Plateau permafrost. Gas hydrate is propitious to occur where the frozen layer is thicker and thermal gradient is lower in the permafrost. Seasonal change of air temperature in Qinghai-Tibet Plateau affects only the uppermost sediments 10m and does not affect gas hydrate that is buried below 30m. Under the global warming, gas hydrate will be unstable and degrade in the permafrost. Its distribution area will be gradually reduced and finally disappear in Qinghai-Tibet Plateau permafrost.
40 citations
"Modeling on Gas Hydrate Formation C..." refers background or methods in this paper
...[24] ever carried out the prediction of gas hydrate occurrences and its volume in the study area just based on of the neighboring gas composition of the Sebei gas filed in the Qaidam basin and the Kela-2 gas field in the Tarim basin....
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...81 m/s (2)); ρ1 is the bulk density of the frozen layer, whose experimental value is 1500-2000 kg/m 3[40~41] and is referred to 1750 kg/m 3 in the modeling([24]);ρ2 is the fluid density below the frozen layer (1000 kg/m (3))....
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