WEBApr 1, 2012 · The gas flow equation of Eq. (33) and the deformation equation of Eq. (7) together describe the interactions among the deformation of coal, free gas flow and gas absorption/desorption in the cleat system and the matrix of coal seam. Fig. 1 graphically presents the fully coupling processes of this developed model in the coal seam gas .
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WEBApr 11, 2024 · Gas extraction is a longterm process; usually coal mines use 180 d as an extraction cycle, so the number of days of extraction for the coal seam was monitored for 30 d, 90 d, and 180 d, and the gas pressure distribution cloud map was plotted when the stress of the overlying rock layer on the coal seam was gradually depressurized from 13 .
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WEBAug 15, 2023 · The extraction process of CBM involves the dewatering of coal seams, enabling the release of trapped methane gas [1].However, one of the primary challenges encountered during CBM production is the significant amount of water that accompanies the extracted gas [2].This water, known as produced water, poses a major problem in terms .
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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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WEBApr 1, 2021 · In coal seam gas industry, induced stress is defined as the modifiion of stress around the fractures during the process of fractures' initiation and propagation (Zhao et al., 2018). Or generally, induced stress is the change of insitu stress caused by factors of loading, unloading, and excavation on the surface or in the subsurface (Su ...
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WEBMay 1, 2021 · The coal and rock mass will produce rapid deformation, crack or fracture change with the action of high stress, and the gas stored in the coal seam will gush out to the working face along the coal seam under the action of the pressure gradient during the tunneling process. These phenomena may produce signals such as AE, EMR, or .
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WEBBai, T, Chen, Z, Aminossadati, SM, Danesh, NN, Pan, Z, Liu, J Li, L 2016, Impact of flow regimes on coal fines generation during coal seam gas production process. in 50th Rock Mechanics/Geomechanics Symposium. 50th US Rock Mechanics / Geomechanics Symposium 2016, vol. 1, American Rock Mechanics Association (ARMA), pp. 356365, .
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WEBNov 7, 2019 · This process is important from both environmental and economic perspectives as coal seam gas is rapidly becoming a popular fuel source worldwide and is a less carbon intensive fuel than coal.
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WEBAug 18, 2021 · The zonal distribution of coal seam gas is the basis for the prediction of coal gas content, gas emission, as well as the key point of gas management. Along the vertical direction (from surface to the deep), the zoning of coal seam gas can be generally divided into the gas weathering zone and methane zone [5, 6].
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WEBNov 1, 2023 · The adsorption characteristics of coal determine that even if the CH 4 pressure in the coal seam is significantly reduced (from MPa to MPa) by conventional negativepressure gas extraction technology, the residual CH 4 content in the coal seam is still as high as about m 3 /t, while the CH 4 content in the coal seam .
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WEBFeb 1, 2019 · 1. Introduction. Coal seam gas (CSG) is an unconventional resource which has been exploited in recent years as a substitute for coal and oil [1].Gas extraction involves decreasing the water pressure which holds the methane in place in the coal cleats [2, 3].Through this process, significant volumes of associated water are produced .
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WEBAug 1, 2022 · M (1. Basic control equation of coal seam. gas migration. Assuming that gas in coal consists of both free and. adsorbed gas, the change in gas mass per unit time in a. control unit body is ...
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WEBDec 15, 2021 · The output process of underground coal seam gas displacement by injecting nitrogen can be divided into two stages approximately. In stage I, driven by the pressure gradient, CH 4 in the original free state is the main product. While in stage II, the desorbed CH 4 from adsorbed state is the main product driven by the concentration .
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WEBFeb 1, 2024 · Abundant industrial experiences have shown that directional air drilling technology is effective for gas drainage when drilling broken and soft coal seams. In this paper, the Eulerian–Eulerian model was used to simulate the gas–solid twophase flow behavior of compressed air transporting coal dust in broken soft coal seams. The .
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WEBJun 20, 2023 · Knowledge of the gas sorption and permeability characteristics of a coal provides an essential basis for the evaluation of coalbed methane reserves and their recoverability. Thus, the gas excess sorption capacities of the main gas component of coal seam gas (CSG) in bituminous coal samples derived from the Xutuan Coal Mine in the .
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WEBNov 6, 2014 · Enhanced coal bed methane recovery (ECBM) is the process in which a displacing gas, such as CO 2 (CO 2ECBM) or N 2 (N 2ECBM) is introduced into the coal seam through an injection well and held there for a sufficient period to enable a substantial amount of methane to be desorbed from the surfaces of the coal seam. Following the .
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WEBWhat is CSG. Coal seam gas is a nonrenewable energy resource that is a byproduct of coal. It is a 'pure' and 'nontoxic' gas and for this reason has attracted a lot of commercial interest. During the process of coal formation, biogenic and thermogenic methane gas forms. Much of this methane remains trapped in the microspores of the ...
WhatsApp: +86 18203695377![[PDF] Development of Intelligent Gas and Coal Seam .](/p5w6rym/413.jpg)
WEBBased on the implementation of an analytic hierarchy process and related investigations, constructed a hierarchical analysis model that optimizes a comprehensive prevention, highefficiency mining technology. ... {Bao2014DevelopmentOI, title={Development of Intelligent Gas and Coal Seam Spontaneous Combustion Sensor Experiment Device .
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WEBCoal seam gas pressure is the core index of coal mine gas disaster prevention and control. Research on active nitrogen injection pressure measurement can effectively shorten the pressure measurement time and is of great significance to improve the pressure measurement efficiency. The purpose of this paper is to study the variation in gas .
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WEBJan 15, 2019 · Effect of coal maturity on CO 2based hydraulic fracturing process in coal seam gas reservoirs. Author links open overlay panel Sampath a, Perera a, D. Elsworth b, Ranjith c, Matthai a, T ... Unlike other potential gas reservoirs, coal seam hydraulic fracturing is quite challenging due to a number of .
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WEBJun 30, 2013 · The major steps for this drilling and completion technique are. Drilling the production hole to the top of the coal seam. Running and cementing casing. Drilling a hole through the coal seam. Increasing the diameter of the hole by a technique known as underreaming (Fig. 1)
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WEBJan 1, 2023 · Coal permeability is a key attribute in determining coal seam methane production and CO 2 storage in coal seam reservoirs [1]. ... Reservoir Engineering in Coal seams: Part 1 the physical process of gas storage and movement in coal seams. SPE Reserv Eng, 2 (1987), pp. 2834, /12514pa. Google Scholar [11] Seidle JP, .
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WEBJun 1, 2021 · Introduction. As the companion of coal seam, coal mine gas (CMG) is a major hazard source to coal mining practice. During the mining process, gas disasters such as gas explosion, gas combustion, and coal and gas outburst may occur, resulting in serious casualties and property losses. 1, 2 Especially when it enters deep mining, .
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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. These reactions can also generate significant amounts of biogenic methane, which often is referred to as swamp gas. ... In general, coal seam gas contents are less than the amount of gas a .
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WEBDec 1, 2019 · 1. Introduction. Coal seam gas (CSG), sometimes refers to coalbed methane (CBM), is a clean energy resource which is generated during the coalifiion process [1, 2].Most of the CSG is stored in the coal seams in an adsorption phase state [3, 4].To improve the gas recovery, other gases are injected into the coal seam to promote the .
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WEBFeb 1, 2024 · The gas migration provides a "material basis" for the gas extraction from the fractured zone of the goaf. The pressurerelief gas from the layer adjacent to the coal seam, as well as the residual gas from the mining process, flow through fracture channels and accumulate in the goaf, creating an area of gas enrichment.
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WEBJun 29, 2023 · To produce coal seam gas (CSG), wells are drilled into underground coal seams, bringing water (CSG water) from the seams to the surface. This process reduces pressure in the seams which allows CSG to be released. The quality of CSG water quality varies greatly, however it is generally rich in salts and other minerals.
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WEBOct 7, 2014 · The longawaited of coal seam gas (CSG) in New South Wales, released last week by the NSW Chief Scientist, highlighted many risks and uncertainties around human health from exposure to toxic CSG ...
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WEBMar 6, 2024 · Thick coal seam fracture stimulations were conducted to enhance pregas drainage efficiency through the use of a highly pressurized multidischarge carbon dioxide gas fracturing technique. This method also offers potential as a strategy for carbon dioxide sequestration, aiding in the reduction of atmospheric carbon dioxide levels and thereby .
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WEBJul 16, 2019 · Coal and gas outburst is a kind of dynamic phenomenon and mainly driven by gas pressure. 12, 13 The coal seams are prone to be fractured, and outburst process will be largely accelerated with the presence of high gas pressure. 14 By and large, the phenomenon of outbursts is the process of coal energy dissipation, 15, 16 which is .
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WEBJan 1, 2017 · The adsorbed gas in the coal seam takes more than 80% of the total, while the content of adsorbed gas mainly depends on the porosity of coal, gas pressure and temperature. ... We combine the MATLAB and the COMSOL Multiphysics to obtain numerical solution and achieve the evolution process of coal and gas outburst .
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WEBApr 11, 2024 · The coals within the No. 3 coal seam exhibit the characteristics of typical anthracite coal and hold a methane gas content ranging from 10 to 37 m 3 /t. This study focuses on the investigation of the historical evolution of methane gas under various occurrence conditions of the coal seam. Download : Download highres image .
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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. The mass exchange between coal matrix and fracture follows Fick's law of diffusion (Yu et al. 2007):
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WEBJun 1, 2022 · The most steeply inclined coal seam is a highgas or outburst coal seam, and protective layer mining is the safest and most effective measure for regional prevention of coal and gas outburst.
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