Several gas extraction enhancing methods have been proposed to improve the gas flow rate and reduce the gas pressure in coal seam, such as CO 2 or gas mixture injection enhanced CH 4 recovery, acid injection for permeability improvement, hydraulic flushing, hydraulic fracturing, etc,. The largediameter drilling expands the contact area between ...
WhatsApp: +86 18037808511Groundwater impacts the removal of groundwater during the gas extraction process may lead to water bores, located in the same aquifer, being impacted (see Gas Guide Chapter 6) ... During the process of producing coal seam gas (CSG), groundwater is extracted in order to reduce water pressure in the coal seams to allow methane gas to be ...
WhatsApp: +86 18037808511In the process of coal mine gas extraction, it is necessary to ensure the effective gas extraction in all directions in the mine so as to prevent and control the gas disaster. ... Xiaocun C, Hui T (2018) Technical scheme and application of pressurerelief gas extraction in multicoal seam mining region. Int J Min Sci Technol 28(3):483489 ...
WhatsApp: +86 18037808511The 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 production. . Mechanical deformation will compact the pore ...
WhatsApp: +86 18037808511sitional flow for the premining coal seam gas extraction. Yang et al. [13] combined the evolution of stress, damage, and gas permeability with the deformation of coal and rock. Gao et al. [14] and Liu et al. [15] considered the thermal effect for extraction of coal seam gas with slotted boreholes.
WhatsApp: +86 18037808511When rockbursts and coal and gas outbursts simultaneously occur in a coal mine, changes in gas adsorption (concentration of ambient methane) and displacement of coal and rock must occur. The coassociated minerals in coal reservoirs can affect the mechanical properties and methane adsorption capacity, which are commonly disregarded. It is important to construct compound molecular structure ...
WhatsApp: +86 18037808511For mines with low permeability and high gas emissions, static blasting technology is used to presplit the coal seam to increase the permeability and strengthen the gas extraction, which will significantly reduce the occurrence of gas accidents in mines. Taking Wangjialing Coal Mine as the research object, the mathematical model of fluidsolid is established. The numerical simulation software ...
WhatsApp: +86 18037808511The 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 ...
WhatsApp: +86 18037808511This study used computer simulation to select appropriate process designs to make coal seam gas (CSG) associated water comply with beneficial reuse regulations. ... 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 ...
WhatsApp: +86 18037808511Coal 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 process to meet engineering quality sealing ...
WhatsApp: +86 18037808511Coal is a black or brownishblack sedimentary rock that can be burned for fuel and used to generate is composed mostly of carbon and hydrocarbons, which contain energy that can be released through combustion (burning). Coal is the largest source of energy for generating electricity in the world, and the most abundant fossil fuel in the United States.
WhatsApp: +86 18037808511Coal seam gas is extracted through wells drilled into coal seams. Australia has relatively large supplies of coal seam gas (CSG) resources, especially in Queensland and New South Wales. CSG has been produced in Queensland from the Bowen Basin since 1997 and in the Surat Basin since 2005.
WhatsApp: +86 18037808511Based on the basic geological data and production data of coalbed methane wells in the Shouyang Block, the characteristics and influencing factors of coalbed methane well production were analyzed, and the primary controlling factors were identified by the grey correlation method. The results show that the average daily gas production of the coalbed methane wells in the study area for the ...
WhatsApp: +86 18037808511water. This releases natural gas from the coal. The gas and water are separated and the gas is piped to compression plants for transportation via gas transmission pipelines. In some cases hydraulic fracturing, or 'fracking', is used to extract coal seam gas. Hydraulic fracturing is the process of injecting fluid under high pressure into a coal
WhatsApp: +86 18037808511In 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 determines precise hole placement spacing for a coal ...
WhatsApp: +86 180378085115. Conclusion. (1) An improved coupled modeling method for coalbed methane extraction after hydraulic fracturing is proposed. It mainly includes two parts: hydraulic fracturing modeling and coupling modeling for coalbed methane extraction. In the first part, we introduce a state damage variable based on damage mechanics theory to record the ...
WhatsApp: +86 18037808511Liquefied 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: 12: 0: 0 ...
WhatsApp: +86 18037808511Coalmeasure gas refers to a set of coalbed methane, coalmeasure shale gas (includes shale gas and certain coalderived gas, abbreviated as shale gas), and tight sandstone gas that are linked ...
WhatsApp: +86 18037808511The efficient preextraction and extraction of coal seam gas resources can not only reduce gas disasters, but also play an essential role in optimising China's energy structure and contributing to "carbon neutrality" [1,2].At present, requirements of "four" extraction management steps (extraction maximisation, extraction standardisation, extraction refinement, and extraction ...
WhatsApp: +86 18037808511Liquid 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 supercharginggasliquid mass transfer", and microscopic ...
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