To produce gas from coal seams, water must be extracted first, lowering the pressure so the gas can flow out of the coal. The volume of groundwater extracted can vary significantly between individual wells, coal seams and coal basins, depending on geological conditions.
1 Introduction. Recovery of coalbed methane (CBM) from coal seams can not only benefit mining safety, reduce greenhouse gas emissions, and also increase clean energy supply (Karacan et al., 2011; Moore, 2012).In the Junggar Basin, the CBM resources have been estimated at trillion cubic meters, which is the third largest CBM basin in China after the Qinshui Basin and Ordos Basin (Fu et al ...
This 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 ...
Coal seam gas extraction is not only a source of clean and natural energy but also a means to address the pressing issue of gas control . Undoubtedly, methane, a crucial element of coal mine gas, is a potent greenhouse gas [ 8 ].
Coal seam gas extraction: modelling groundwater impacts . uncertainty analysis, presentation and documentation of outputs). The modelling process is influenced by, objectives, conditions, data and scale of impact. Groundwater modelling tools . Groundwater modelling tools can simulate the potential groundwater impacts from coal seam gas production.
sitional 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.
The widely spread CarboniferousPermian coal seam group in southern China has great potential for coalbed methane resources, but the extensively developed tectonically deformed coal seriously restricts its development. Taking the Dahebian block in western Guizhou as the study area, the geological model of coalbed methane reservoirs in the tectonically deformed coal seam group was established ...
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 ...
In fact, 20 times the amount of energy you would do from a similar coal seam gas extraction process. MARK HORSTMAN: ... View the clip 'Coal seam gas production' for more information.
water. 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
The insitu gasification process (ISG) produces methane, hydrogen and other valuable components. The synthetic gas (syngas) can be used to produce electricity directly or further refined into a variety of products including synthetic methane and ammonia. The ISG demonstration project was built to inform the design for a potential commercial ...
Coal Seam Gas Extraction by Integrated Drillings and Punchings from the Floor Roadway considering HydraulicMechanical Coupling Effect Geofluids / 2022 / Article Special Issue NonAqueous Fracturing for Unconventional Oil, Gas, and Geothermal Reservoirs View this Special Issue Research Article | Open Access
The sealing quality of the gas extraction holes determines the extracted gas concentration. Based on this, the paper reveals the basic principle of hole sealing by analyzing the gas leakage mechanism of the borehole. The hole sealing technology of solidliquid materials with three pluggings and two injections for the gas extraction hole is proposed, and the hole sealing device and material ...
1. Introduction. The efficient extraction of gas ensures the safe production of coal mines. It also contributes to clean energy and reduces methane emissions in the process of coal mining. 1,2 In fact, it can be used as a carbon emission reduction approach for coal enterprises and a positive response to the goal of "carbon peaking and carbon neutrality".
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 ...
When 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 ...
Exploring the evolution characteristics of gas seepage between boreholes during the drainage process is critical for the borehole's layout and highefficiency gas drainage. Based on the dualporous medium assumption and considering the effect of stress redistribution on coal seam gas seepage characteristics, a coal seam gas seepage model with a threedimensional roadway and borehole crossing ...
Coal seam gas overall process The development of unconventional gas resources such as shale gas and coal seam gas has boomed over the past few years [1]. Coal seam gas (CSG) also known as coal bed methane (CBM) is comprised of natural gas that is extracted from low to high rank coal beds [2], [3].
CSG is extracted through wells drilled into coal seams. The initial phase of CSG production usually involves the extraction of water from the coal seams in order to reduce the pressure and release gas from the coal. If the pressure within the seam is high, the gas may flow to the surface unaided.
5. 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 ...
Coalmeasure 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 ...
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 supercharginggasliquid mass transfer", and microscopic ...
Based 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 ...
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 production. . Mechanical deformation will compact the pore ...
Gas preextraction technology in a coal reservoir can not only reduce greenhouse gas (GHG) emissions but also effectively recover coalbed methane (CBM). In this work, we use a geomechanicalcoupled gas flow (GCF) model to simulate and analyze the preextraction effect of a miningdisturbed coal seam. First, the simulation results of the GCF model are compared with field test data to verify the ...
Coal seam predrainage technology is widely used to prevent and control gas in China's highgas coal seams, and upward drilling is a safe and reliable technology. Using the Luling Coal Mine as the study location, according to the actual situation of the site, a layerthrough drilling process was proposed. Relying on a crosslayer extraction borehole, coal seam water injection efficiency ...
Groundwater 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 ...
1. Introduction Coalbed methane (CBM) is an important associated resource, which is generated during the coal formation process and stored within the coal seam. Since coal has gradually entered the deep mining stage, its geology has become more complex, and its properties of low permeability are becoming more prominent.
A large amount of CH 4 gas is stored in coal matrixes through the adsorption process at greater pore fluid pressure. As a result, when the pore pressure reduces to cause the desorption process to desorb this stored CH 4 gas, the CH 4 gas can be continuously produced. To reduce the pore fluid pressure, first naturally remaining pore water is pumped out through a drilled well and then along with ...
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