WEBSep 15, 2023 · Liquid CO 2 injection into coal seam for CH 4 displacement is one of the important means to strengthen gas extraction and carbon sequestration in recent years. After liquid CO 2 is injected into coal seam, physical and chemical interactions occur with coal through the process of "liquid phase seepagephase transformation supercharging .
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WEBMay 9, 2018 · Coal seam gas (CSG) is an increasingly important source of natural gas all over the world. Although the influence of conventional oil and gas extraction on surface subsidence has been widely ...
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WEBNov 8, 2018 · By using the fluidsolid coupling model of coal seam gas extraction, the law of gas extraction under the above two types is simulated so as to determine the reasonable way of borehole distribution. Figure 7 is the distribution map of gas pressure in the unloaded coal seam with gas extraction up to 180 days. Obviously, the initial gas .
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WEBOct 27, 2023 · The gas extraction quantity is affected by gas pressure, permeability, and coal seam buried depth in the actual process of gas extraction, which is variable and complex. There is an interaction influence between each factor, which provides us with valuable guidance for analyzing the coupling change law of gas extraction quantity.
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WEBFeb 26, 2022 · The highest gas pressure and the maximum gas content in the coal seam were MPa and m 3 /t, respectively. There was a high coal and gas outburst hazard in the coal seam and, therefore, it was necessary to improve the elaborate identifiion and realtime monitoring on the outbursthazardous zones in the coal seam.
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WEBMay 2, 2018 · The temperature of the coal seam will be lower than ambient temperature after gas extraction because of the endothermic process, as a result, heat energy flows from the environment into the coal seam. ... Liu,, Cheng,, Jiang,, Li, W., Jin, K.: Interactions between coal seam gas drainage boreholes and the impact of such on ...
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WEBJan 1, 2021 · Airleakage is one of the main reasons leading to poor coal seam gas (CSG) extraction performance, and needs to be mitigated urgently. ... and (Wang et al., 2021a,b) conducted an experimental study on the air leakage process of coal seam gas drainage by using an integrated apparatus in the laboratory. Although this has a certain reference .
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WEBMay 21, 2015 · By integrating coal production with gas extraction, coal seam gas becomes a useful resource. Advantage is taken of the effect of strata movement on gas pressurerelief and flow during the coal mining process to establish a single production system for simultaneous coal and gas extraction.
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WEBDOI: / Corpus ID: ; Study on gas seepage from coal seams in the distance between boreholes for gas extraction article{Zhao2018StudyOG, title={Study on gas seepage from coal seams in the distance between boreholes for gas extraction}, author={Dan Zhao and Jian Liu and Jingtao Pan}, journal={Journal of Loss .
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WEBJan 19, 2016 · Biochemical reactions associated with this process transform the organic matter into humic substances, which are the precursors of coal macerals. ... an isotherm should be obtained from each major coal seam. These isotherms can be used to determine the saturation state and estimate a recovery factor by comparing the expected gas .
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WEBRealizing efficient gas drainage in low permeability coal seams has always been a difficult problem for coal miners. Based on this, this paper proposes a new technology of largediameter mechanical cavemaking to promote gas extraction in a coal seam. This technology mainly uses the pressure of a water injection pump to control the automatic .
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WEBApr 19, 2022 · As a result, it is difficult for the coal seam sealing process to meet engineering quality sealing requirements, which results in problems such as low gas concentration during the extraction process.
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WEBApr 1, 2022 · Section snippets Basic assumptions. Coal seams generally contain both coal matrix and fractures, which are typical of dualporosity media [52]. To simplify the methane gas flow process in coal as much as possible, we refer to previous literature [12], [51] when building the dualporosity model of coal bodies and make the following .
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WEBAlthough numerous studies have tried to explain the mechanism of directional hydraulic fracturing in a coal seam, few of them have been conducted on gas migration stimulated by directional hydraulic fracturing during coal mine methane extraction. In this study, a fully coupled multiscale model to stimulate gas extraction from a coal seam stimulated .
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WEBNov 3, 2023 · The indirect method is to predict the gas content of coal seam by gas emission and adsorption isotherm curve 14,15,16. Permeability is a key factor to determine the development process and ...
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WEBJun 1, 2024 · At present, a large area is drilled through the layer in the floorrock roadway to predrain coal seam gas as an outburst prevention measure [45, 46]. However, during the later stages of gas extraction, the gas extraction flow and gas concentration are low, and the extraction efficiency is also low [47].
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WEBMay 26, 2023 · Coal as the main energy source in the process of industrialization is necessary to ensure rapid economic development (Balat et al. 2010; Wang et al. 2020; Xiang et al. 2021).However, the coal bed conditions are complex in China (, high gas content) potential causing ous safety problems in the process of coal mining, especially .
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WEBFeb 16, 2023 · Mining coal. Coal miners use large machines to remove coal from the earth. Many coal deposits, called coal beds or seams, are near the earth's surface, but others are deep mining methods allow coal miners to easily reach most of the nation's coal reserves and to produce about three times more coal in .
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WEBJun 14, 2023 · The FLAC 3D numerical simulation software simulated the gas extraction process from the coal seam using directional boreholes. Optimal drilling parameters were determined by analyzing plasticity, stress, and enhanced permeability zone distribution patterns during gas extraction with different borehole radii. A .
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WEBApr 19, 2022 · Coal is affected by the concentrated stress disturbance of mining, the disturbance of drilling hole formation, and the concentrated stress of coal shrinkage and splitting of gas desorption from the hole wall; these result in a large number of secondary cracks that collect and leak gas. As a result, it is difficult for the coal seam sealing .
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WEBThe coal seam gas debate. In this section. Dr Alex St John, Science, Technology, Environment and Resources. Key issue. Coal seam gas (CSG) is a polarising issue in some communities. Proponents argue that CSG is a vital energy resource, necessary for continued gas supply. Opponents claim that CSG could have serious environmental and .
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WEBMay 15, 2024 · As the initial coal seam temperature during the gas extraction process increases, the disparity between the coal seam temperature and the initial temperature becomes more pronounced, as illustrated in Figure 21. This is because as the initial coal seam temperature rises, the desorption amount of gas at the same extraction time also .
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WEBFeb 13, 2020 · Coal seams, particularly deep unmineable coal reservoirs, are the most important geological desirable formations to store CO2 for mitigating the emissions of greenhouse gas. An advantage of this process is that a huge quantity of CO2 can be sequestrated and stored at relatively low pressure, which will reduce the amount of .
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WEBMay 10, 2024 · During the gas extraction drilling process, especially the soft coal seam drilling process, due to the constraints of geological conditions, technical conditions, and other factors, it is easy to encounter stuck holes, blowout, lost circulation, and hole collapse, which affect the realization of efficient gas management. In the petroleum industry, .
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