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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WEBNov 1, 2022 · The above methods of strengthening coal seam gas extraction introduces one or more gases into the coal seam. The influence of such methods on coal seam gas migration still needs further discussion. ... In summary, other key scientific issues involved in the process of coal mine gas extraction are to reveal the flow state of fluid in the cross ...
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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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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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WEBOct 1, 2020 · Typically, the gas reserves are loed in coal seams which are several hundred meters below ground. The extraction process involves depressurization of the seams [3], which results in the collection of substantial amounts of CSG associated water which is saline in character [4].
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WEBOct 26, 2023 · In order to develop precise hole placement technology for gas extraction, this paper combines industrial testing, the evolution law of coal rock damage permeability, and the coal doublepore doublepermeability model; establishes a coupling model of the coal damage deformation field and matrixfracture double diffusion seepage field; and .
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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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WEBOct 1, 2019 · The selection of proppants is critical in the coal seam gas extraction process, where the softer coal rock surface restricts the use of high strength proppants due to its vulnerability of embedding into the surface. 2) coal properties – elastic modulus of coal is the most important factor deciding the proppant behaviour in the extraction ...
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WEBJul 7, 2023 · Gas disasters have become one of the factors seriously affecting mine safety production. 2,3 Gas pressure is an important indior for preventing gas disasters, which directly reflects the gas content in coal seams and the potential danger level of coal and gas outbursts. 4−6 However, accurate measurement of coal seam gas pressure is very ...
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WEBSep 20, 2019 · Coal Seam Gas: Evaluation, Extraction, and Environmental Issues. September 2019. DOI: /. In book: Sustainable Energy and Environment () Authors: Debadutta Mohanty ...
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WEBCoalbed methane extraction. Coalbed methane extraction (CBM extraction) is a method for extracting methane from a coal deposit. Coal bed methane (CBM) is one of the factors restricting the safe production of coal in underground coal mines. It is also a form of highquality energy that can be used in many fields such as power generation, heating ...
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WEBJun 7, 2022 · 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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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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WEBJan 1, 2023 · Coal permeability is a crucial property for coal seam gas production. In previous studies, it was assumed that both matrix blocks and coal bridges share an average equalized gas pressure.
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WEBFeb 5, 2024 · More and more gas extraction in deep coal seam is conducted under extreme geological conditions. The coal permeability determines the efficiency of gas extraction. To research the evolution of permeability and gas seepage in deep coal seam under threedimensional (3D) stress condition, a permeability model (DCTDS model) .
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WEBSep 1, 2015 · Despite long extraction times, the amount of extracted gas is very low due to low gas permeability in Chinese coal seams. Therefore, the coal seam requires significant structural changes to improve the efficiency of the gasextraction process and reduce the gasextraction time (Zhou et al., 2012).
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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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WEBJun 21, 2023 · Coal Seam Gas. Coal Seam Gas (CSG) is a naturally occurring methane gas found in most coal seams and is similar to conventional natural gas. In Australia the commercial production of CSG commenced in 1996 in the Bowen Basin, Queensland. Since then production has increased rapidly, particularly during the first decade of the .
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WEBSep 19, 2023 · The gas migration process in the coal seam can be divided into gas desorption and diffusion in the matrix to the fractures and then into the borehole through seepage. ... Zhang J, Liu Y, Ren P, Han H, Zhang S (2021) A fully multifield coupling model of gas extraction and air leakage for inseam borehole. Energy Rep 7:1293–1305
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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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WEBJun 6, 2022 · The coal output of a single cave is approximately t/m, and the pressure relief effect is obvious. When the measurement range is 50 m, the average gas concentration for the mechanical cavitation drilling is 50%. The net amount of gas drainage is m 3 /min. The net volume of single cycle drainage is 60,480 m 3.
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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. In this paper, based on the analysis of coal pore and fissure characteristics, and in view of the current situation of gas drainage and .
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WEBThe initial phase of CSG production usually involves the extraction of formation water from the coal seams in order to reduce the water pressure and release gas from the coal. At the surface, water in the gas is separated and piped elsewhere for use or further treatment. Gas from underground coal gasifiion (UCG) is sometimes confused with ...
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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 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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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 1, 2022 · The process of deformation and failure of coal sample ZZ3 was simulated using the ... The underground coal seam gas extraction project is ... Based on the Darcy's law in the flow of gas in the ...
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WEBApr 1, 2013 · 1. Introduction. Reservoir compaction may accentuate the nonDarcy flow and induce the anisotropy of permeability during both conventional gas production and unconventional gas (such as coal seam gas) extraction (Clarkson et al., 2007, Majewska et al., 2010, Zeng et al., 2003).The gas flow in porous media is usually pressuredriven .
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WEBJul 16, 2022 · The slitting pressure is set to 100 MPa. The 3# coal seam is the main mining seam, the original gas pressure of the second panel area of the 3# coal seam is MPa, the original gas content is ~ m 3 /t, the firmness coefficient is about, and the permeability coefficient of 3# coal seam is ~ MPa 2 ·d.
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WEBApr 1, 2022 · Gas extraction and transport process in coal seam (a) gas flow field (b) mesh generation. Fig. 3 (b) shows the mesh division and the node numbering of the solution area. The mesh nodes in the x axis direction past the point (0, N ) belong to the fracture flow field, and the intersection of x axis and r axis horizontal along vertical mesh ...
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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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WEBCoal seam gas (CSG) is a type of natural gas that is found in coal deposits. It is classified as an unconventional gas resource because it contains a high concentration of methane. CSG is produced by extracting water from the formation, which reduces the pressure and releases the gas from the coal seam. The gas extraction process produces a ...
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WEBApr 17, 2019 · 1 INTRODUCTION. China is one of the countries with the largest coalbed methane resources. The exploration and development of CBM resources are of great significance for ensuring the safe production of the coal mine, improving the energy structure and purifying the environment in China. 13 CBM is a kind of unconventional .
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WEBMay 1, 2021 · This process of parameter estimation in the absence of direct calibration is called regionalisation. ... In particular, these pathways include the effects of groundwater extraction – which is common to coal seam gas extraction and to both surface and underground mining – and of the controlled collapse of underground voids.
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