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 ...
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.
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 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
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.
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 recognized and studied, few studies are carried out on the surface subsidence in coal seam gas fields and its impact on surface infrastructure and the environment. This paper discusses modelling of the ...
The China national coal mining depth is going deeper and deeper as the average annual rate of 1050 m [20].The mining depth of many coal mines in MidEast of China has reached m below surface ( 800 m in Huaibei, 850 m in Huainan, and 1000 m in Xuzhou).At these mining depths, the coal seam overburden stress ranges from 22 to 33 MPa and the coal seam gas pressure and gas content ...
In order to reveal the process and mechanism of gas flow in a lowpermeability coal seam, a new multiplerelaxationtime lattice Boltzmann method (MRTLBM) model of gas migration in coal micro/nanopores based on Langmuir monolayer adsorption theory, the slip boundary scheme and Bosanquet effective viscosity was established. The software MATLAB was used to carry out the simulation study of ...
Download Coal seam gas extraction and coproduced water (PDF ) What is coproduced water? Coal seam gas is a natural gas held in coal seams under pressure by groundwater. Coal seam gas wells release the gas by reducing the pressure through groundwater extraction.
Liquefied 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 ...
In order to solve the problem that the gas in the upper corner is easy to exceed the limit in the mining process of the deep outburst coal seam. Based on the theory of "Oring" and the distribution of stratigraphy in the field, the development law of mining fissures in the overlying rock layer during the workface retrieval was studied by combining theoretical calculation and ...
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 ...
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 ...
For the gas extraction process, the larger the plastic zone created by the coal body around the borehole, the wider the range of fissures created and the greater the permeability, the more conducive to gas extraction and the increase in extraction rate. ... "Numerical Simulation of Gas Extraction in Coal Seam Strengthened by Static Blasting ...
Environmental impact of coal mining and coal seam gas production on surface water quality in the Sydney basin, Australia. Environ Monit Assess. 2017 Aug;189(8):408. doi: /s . It also contributes to greenhouse gas emissions, both through the direct release of methane during extraction and the burning of the gas for energy.
Coal mine gas accidents have been one of the most serious disasters in the process of coal mining in China that seriously affect the safety of mine production and the life safety of miners. (1−5) At present, the fundamental method to prevent coal seam gas disasters is to increase the permeability of coal seam.
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
From this, the primary equipment and key production technologies were determined for the proposed softrock protective seam mining. Finally, in combination with the optimal arrangement of the working face, the pressurerelief gas extraction technology accomplished the pressurerelief mining of the protected coal seam. 2.
In 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 ...
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 ...
In order to improve the efficiency of gas extraction in coal mines, a datadriven finemanagement and control method for gas extraction is proposed. Firstly, the accurate prediction of coal seam thickness and gas content was used to evaluate the gas reserves. Based on the time relationship between mining activities and gas extraction, the calculation model of borehole distance in different ...
Gas transport mechanism during coalbed gas extraction process . ... the coal seam with low gas content and without outburst risk is chosen as the first coal seam to be mined. As shown in Figure 13, the rock mass moved to the gob after the first coal seam was mined. Then, it formed three zones above the mining coal seam: caving zone, fractures ...
In the process of coal seam gas extraction, a large number of extraction boreholes are arranged in the coal seam. When there are more extraction boreholes arranged along the strike and dip of the coal seam, the values of m and n are larger. The number of inquadrangle borehole layouts will mainly depend on 2 mn items. Compared with the ...
Previous research on protective seam mining and pressure relief gas extraction technology, found that any slight expansion and deformation of the coal seam causes a dramatic increase in the permeability coefficient of the coal seam (Yin et al., 2015). Therefore, increasing a coal seam's permeability can be achieved by enlarging the permeable ...
Within the USA, both coal seam gas (8% of total natural gas produced) and shale gas industries (30% of total) are in substantial growth phases. Although A. Gore, D and Davies, P (2013) Department of Environment and Geography, Macquarie University, Background paper on produced water and solids in relation to coal seam gas production: Report
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 ...
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".
© DZCrusher - كل الحقوق محفوظة
