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 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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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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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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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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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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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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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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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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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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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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WEBLiquefied natural gas (LNG) is a natural gas that has been cooled to minus 162°C, a process that is commonly done for gas export purposes as it reduces the volume of the transported gas. ... Conventional gas Coal seam gas; Cumulative production Reserves (2P) Resources (2C) Cumulative production Reserves (2P) Resources (2C) Adavale: 9: .
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WEBDownload scientific diagram | Coal seam gas production process (created by the author using data from Rice and Nuccio 2000) from publiion: A study on the carbon dioxide injection into coal seam ...
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WEBJan 15, 2019 · One potential source of energy is extraction of unconventional gases, such as basincentered gas, tight gas, coal seam gas (CSG) and shale gas [1]. The extraction of natural gas from low permeability unconventional reservoirs requires methods to improve access to the reservoir. 'Hydraulic fracturing' is one such technique which has made gas ...
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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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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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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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WEBDec 15, 2021 · 1. Introduction. According to the Global Energy Statistical Yearbook 2020, the total proven reserves of natural gas worldwide amount to trillion m total production is billion m 3, and the total consumption is 3, billion m 3 with a share of % in primary energy [1].Coal seam gas (CSG) accounts for 6%–9% of .
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WEBDec 9, 2023 · Efficient gas extraction is important for reducing coal mine gas accidents and protecting the environment. A prerequisite for achieving efficient gas drainage is to clarify the evolution rules of mining fractures and the development characteristics of gas migration channels. In this study, aiming at the rock structure of coal seam composite .
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WEBJan 7, 2009 · A mathematical model was developed to predict the coal bed methane (CBM) production and carbon dioxide (CO 2) sequestration in a coal seam accounting for the coal seam model predictions showed that, for a CBM production and dewatering process, the pressure could be reduced from MPa to MPa and .
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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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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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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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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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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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