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.
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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.
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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: 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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TL;DR: Based on the records of 6 stations in Jiangxi regional seismic network and CSN, this paper obtained the focal mechanisms of the MS5.7 Jiujiang-Ruichang earthquake and its MS4.8 aftershock of Nov.26, 2005 with the “Cut and Paste” (CAP) method, and analyzed the seismogenic structure by combining with relocation of the aftershock sequence and the geologic settings in the region.
Abstract: Based on the records of 6 stations in Jiangxi regional seismic network and CSN, we obtained the focal mechanisms of the MS5.7 Jiujiang-Ruichang earthquake and its MS4.8 aftershock of Nov.26, 2005 with the “Cut and Paste” (CAP) method, and analyzed the seismogenic structure by combining with relocation of the aftershock sequence and the geologic settings in the region. Our result shows that the best double couple solution of the MS5.7 event is 324°, 55° and 18° for strike, dip, and rake angles respectively, the other nodal plane is 223°, 75°, and 144°, for the MS4.8 aftershock the solution is 54°, 71°, and –160° with the other nodal plane of 317°, 71° and –20° respectively. Complexities can be found in the aftershock and source depth distributions of the sequence. After the occurrence of the MS5.7 main shock, aftershocks occurred and propagated from SE to NW and from shallower to deeper crust, then they probably encountered an asperity and triggered the MS4.8 strong aftershock. This complexity and the different focal mechanisms imply that the two earthquakes may not occur on the same fault. We infer that the MS5.7 main shock was caused by the NW striking Yangjishan-Wushan-Tongjiangling fault buried in Ruichang basin and the MS4.8 aftershock occurred on the NE striking Dingjiashan-Guilinqiao-Wuning fault in the northwest margin of the basin.
8 citations
Journal Article•
TL;DR: In this paper, the authors discussed the forming conditions of natural gas hydrates, the tectonic unit division and the ever-permafrost characteristics in the Qiangtang basin.
Abstract: The natural gas hydrates are one of the new energy resources of the 21_(st) century, and many countries in the world pay great attention to investigation of the natural gas hydrates. In the north of Qinghai-Tibet plateau, there is an unique series of marine Jurassic sediments in Qiangtang basin which is the rich gas resources, traps and permafrost strata . The author discusses the forming conditions of natural gas hydrates, the tectonic unit division and the ever-permafrost characteristics. At the same time, the author placed emphasis on the geophysics recognition and prediction of natural gas hydrates . In accordance with the related analyses, the geological conditions are favorable for the natural gas hydrates exploration in permafrost zone. Taking long views,the investigation of gas hydrates in Qiangtang basin should be carried out as soon as possible.
7 citations
TL;DR: In this paper, brightness temperature anomalies recorded by satellite-based thermal infrared remotely sensed images before or within the imminent earthquake, the high content of hydrocarbon gas acid-degassed from subsurface sediment and the high radioactive thermoluminescence value were found in the region.
Abstract: Gas hydrate, mainly composed of hydrocarbon gas and water, is considered to be a clean energy in the 21st century. Many indicators such as BSRs (Bottom-Simulating Reflections), which are thought to be related to gas hydrate, are found in the South China Sea (SCS) in recent years. The northeastern part of the SCS is taken as one of the most potentials in the area by many scientists. It is situated in the conjunction of the northern divergent continental margin and the eastern convergent island margin, whose geological settings are much preferable for gas hydrate to occur. Through this study, brightness temperature anomalies recorded by satellite-based thermal infrared remotely sensed images before or within the imminent earthquake, the high content of hydrocarbon gas acid-degassed from subsurface sediment and the high radioactive thermoluminescence value of subsurface sediment were found in the region. Sometimes brightness temperature anomalies alone exist in the surrounding of the Dongsha Islands. The highest content of hydrocarbon gas amounts to 393 μL methane per kilogram sediment and the highest radioactive thermoluminescence value is 31752 unit; their geometric averages are 60,5 μL/kg and 2688.9 unit respectively. What is more inspiring is that there are three sites where the methane contents are up to 243, 268 and 359 μL/kg and their radioactive thermoluminescence values are 8430, 9537 and 20826 unit respectively. These three locations are just in the vicinity of one of the highest confident BSRs identified by predecessors. Meanwhile, the anomalies are generally coincident with other results such as headspace gas anomaly in the sediment and chloride anomaly in the interstitial water in the site 1146 of Leg 184. The above-mentioned anomalies are most possibly to indicate the occurrence of gas hydrate in the northeastern SCS.
7 citations
Journal Article•
TL;DR: Using an additional damage concept, a relationship has been developed between frozen soil density and computerized topography (CT), regardless of the initial degree of saturation, so that a calculation model between CT number and inner additional damage is put forward.
Abstract: Using an additional damage concept, a relationship has been developed between frozen soil density and \%CT\% number of computerized topography (CT), regardless of the initial degree of saturation, so that a calculation model between \%CT\% number and inner additional damage is put forward. Thus, the relationship of \%CT\% number and gaps, which appear along loading process, can be ascertained. Calculation methods for ascertaining initial damage in specimens are suggestedas follows. Firstly, to prepare a perfect sample without any flaw, and then to detect the \%CT\% number of its initial state as \%H 0\% Secondly, to calculate \%CT\% number\% H\+\+1\-\-0\% of supposedly perfect sample but with difference density, and then to calculate the initial damage value D for samples with flaws. This step has been carried out for two series of frozen soil samples, and additional damage values under loading of one set of saturated samples can be determined.[FQ(1?46,ZX,BP,DY-W]
7 citations
6 citations