scholarly journals Numerical Simulation of Migration and Distribution Law for Gas Seepage in Coal Seam

2019 ◽  
Vol 37 (3) ◽  
pp. 761-765
Author(s):  
Jiaxin Dong ◽  
Lei Cheng
Keyword(s):  
Numerical Simulation ◽  
Coal Seam ◽  
Distribution Law ◽  
Gas Seepage

Numerical Simulation of Gas Distribution and Mined Seepage Passage with the Pressure Relief of Short Distance Protective Coal Stratum

2011 ◽  
Vol 105-107 ◽  
pp. 1517-1520
Author(s):  
Yong Jun Zhang ◽  
Nian Jie Ma ◽  
Zi Min Zhang ◽  
Tian Rang Jia
Keyword(s):  
Numerical Simulation ◽  
Coal Seam ◽  
Gas Permeability ◽  
Process Analysis ◽  
Failure Process ◽  
Numerical Approach ◽  
Gas Seepage ◽  
Coal Rock ◽  
Rock Model ◽  
Stress Damage

With the full consideration of the heterogeneity, existing joints, and cracks in the rock, the coupled gas-rock model for investigating the failure process of coal-rock is established by introducing the related equations governing the evolution of stress, damage and gas permeability along with the deformation of coal and rock. A numerical approach of realistic failure process analysis (RFPA) to simulate the stratum movement, layer separation, the whole collapse progresses, and gas permeability changing of the protected coal seam is proposed. The numerical simulation results well displayed the whole processes of the cracks growth of gas seepage passage and the change of gas permeability for the closed distance protected coal seam. It can be seen from the distribution of acoustic emission in the space that the stratum failure is transferred from deeper to surface. By the analysis of the stress fields changing, the reasons of the gas permeability improvement of the protected coal seam are presented.

scholarly journals Numerical and Similarity Simulation Study on the Protection Effect of Composite Protective Layer Mining with Gently Inclined Thick Coal Seam

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jianhong Ma ◽  
Chao Hou ◽  
Jiangtao Hou
Keyword(s):  
Numerical Simulation ◽  
Coal Seam ◽  
Simulation Analysis ◽  
Protective Layer ◽  
Vertical Displacement ◽  
Vertical Stress ◽  
Distribution Law ◽  
Gas Drainage ◽  
Thick Coal Seam ◽  
Maximum Expansion

Protective layer mining, as a dominating method for preventing coal and gas outburst, is generally adopted in highly gassy coal mines. In the absence of a suitable thickness coal seam to serve as the protective layer, the rock-coal composite protective layer was proposed in this paper. We conducted a series of simulations and engineering measurements to investigate the protective effect under the mining of the rock-coal composite protective layer of the Zhongtai coal mine located in the Hebi area of Henan, China. The numerical simulation analysis showed that, after the completion of protective layer mining, the minimum vertical stress of the No. 2-1 coal seam had been reduced to 3.46 MPa. The maximum vertical displacement of the No. 2-1 coal seam is 455.01 mm. The maximum expansion deformation of the No. 2-1 coal seam is 9.77‰; the effective pressure relief range is as long as 160 m. The similarity simulation experiment revealed that, after the completion of protective layer mining, the minimum vertical stress of the No. 2-1 coal seam is 4.0 MPa. The maximum vertical displacement of the No. 2-1 coal seam is 640 mm. The maximum expansion deformation of the No. 2-1 coal seam is 26.37‰; the effective protection range reaches 130 m. The engineering measurements demonstrated that the variation law of gas drainage parameters in the protected layer corresponds to the protected layer's vertical stress distribution law in numerical simulation and similarity simulation. With the exploitation of the composite protective layer, the protective layer’s pressure begins to release. The average gas drainage concentration is 2-3 times of that before the composite protective layer mining.

scholarly journals Numerical Analysis on the Storage of Nuclear Waste in Gas-Saturated Deep Coal Seam

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Teng Teng ◽  
Yuming Wang ◽  
Xiaoyan Zhu ◽  
Xiangyang Zhang ◽  
Sihai Yi ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Coal Seam ◽  
Modeling And Simulation ◽  
Nuclear Waste ◽  
Nuclear Power ◽  
Geological Storage ◽  
Storage Chamber ◽  
Coal Deformation ◽  
Gas Seepage ◽  
Central Storage

Nuclear power has contributed humanity a lot since its successful usage in electricity power generation. According to the global statistics, nuclear power accounts for 16% of the total electricity generation in 2020. However, the rapid development of nuclear power also brings up some problems, in which the storage of nuclear waste is the thorny one. This work carries out a series of modeling and simulation analysis on the geological storage of nuclear waste in a gas-saturated deep coal seam. As the first step, a coupled heat-solid-gas model with three constitutional fields of heat transfer, coal deformation, and gas seepage that based on three governing conservation equations is proposed. The approved mechanical model covers series of interactive influences among temperature change, dual permeability of coal, thermal stress, and gas sorption. As the second step, a finite element numerical model and numerical simulation are developed to analyze the storage of nuclear waste in a gas-saturated deep coal seam based on the partial differential equations (PDE) solver of COMSOL Multiphysics with MATLAB. The numerical simulation is implemented and solved then to draw the following conclusions as the nuclear waste chamber heats up the surrounding coal seam firstly in the initial storage stage of 400 years and then be heated by the far-field reservoir. The initial velocity of gas flow decreases gradually with the increment of distance from the storage chamber. Coal gas flows outward from the central storage chamber to the outer area in the first 100 years when the gas pressure in the region nearby the central storage chamber is higher than that in the far region and flows back then while the temperature in the outer region is higher. The modeling and simulation studies are expected to provide a deep understanding on the geological storage of nuclear waste.

A Simulative Method on Gas Seepage in Coal Seam around Borehole

2013 ◽  
Vol 353-356 ◽  
pp. 3176-3181 ◽  
Author(s):  
Guo Qiang Cheng ◽  
Yi Wang
Keyword(s):  
Numerical Simulation ◽  
Coal Seam ◽  
Thermal Conduction ◽  
Emission Rate ◽  
Early Stage ◽  
Simulation Method ◽  
Actual Situation ◽  
Gas Emission ◽  
Gas Seepage ◽  
Theoretical Results

Based on the analogy between equations of gas seepage in coal seam and that of thermal conduction, a simulative method on gas seepage in coal seam was proposed through that thermal conduction interpreted as gas seepage. The laws of gas emission from borehole in homogeneous and heterogeneous coal seam were analyzed using this method. It indicates that the simulative results of the gas emission from borehole in homogeneous coal seam were satisfied with the corresponding theoretical results during the early stage of gas seepage, while a tolerance between the numerical results and the theoretical ones was appeared in the later period. This is due to the simplification as solving the theoretical equations. The results of heterogeneous coal seam show that curves of gas emission rate conform to the actual situation. The numerical simulation method on the law of gas emission from borehole in coal seam is feasible.

Reasonable Entry Layout of Lower Seam in Multi-Seam Mining Based on Numerical Simulation

2013 ◽  
Vol 295-298 ◽  
pp. 2980-2984
Author(s):  
Xiang Qian Wang ◽  
Da Fa Yin ◽  
Zhao Ning Gao ◽  
Qi Feng Zhao
Keyword(s):  
Numerical Simulation ◽  
Stress Distribution ◽  
Coal Seam ◽  
Coal Mine ◽  
Abutment Pressure ◽  
Surrounding Rock ◽  
Geological Conditions ◽  
Seam Mining

Based on the geological conditions of 6# coal seam and 8# coal seam in Xieqiao Coal Mine, to determine reasonable entry layout of lower seam in multi-seam mining, alternate internal entry layout, alternate exterior entry layout and overlapping entry layout were put forward and simulated by FLAC3D. Then stress distribution and displacement characteristics of surrounding rock were analyzed in the three ways of entry layout, leading to the conclusion that alternate internal entry layout is a better choice for multi-seam mining, for which makes the entry located in stress reduce zone and reduces the influence of abutment pressure of upper coal seam mining to a certain extent,. And the mining practice of Xieqiao Coal Mine tested the results, which will offer a beneficial reference for entry layout with similar geological conditions in multi-seam mining.

scholarly journals A numerical simulation of realistic top coal caving intervals under different top coal thicknesses in longwall top coal caving working face

2021 ◽  
Author(s):  
Chuang Liu ◽  
Huamin Li
Keyword(s):  
Numerical Simulation ◽  
Coal Seam ◽  
Distinct Element ◽  
Simulation Models ◽  
Simulation Software ◽  
Thick Coal Seam ◽  
Coal Recovery ◽  
Working Face ◽  
Longwall Top Coal Caving ◽  
Selection Of

Abstract In the process of longwall top coal caving, the selection of the top coal caving interval along the advancing direction of the working face has an important effect on the top coal recovery. To explore a realistic top coal caving interval of the longwall top coal caving working face, longwall top coal caving panel 8202 in the Tongxin Coal Mine is used as an example, and 30 numerical simulation models are established by using Continuum-based Distinct Element Method (CDEM) simulation software to study the top coal recovery with 4.0 m, 8.0 m, 12.0 m, 16.0 m, 20.0 m and 24.0 m top coal thicknesses and 0.8 m, 1.0 m, 1.2 m, 1.6 m and 2.4 m top coal caving intervals. The results show that with an increase in the top coal caving interval, the single top coal caving amount increases. The top coal recovery is the highest with a 0.8 m top coal caving interval when the thickness of the top coal is less than 4.0 m, and it is the highest with a 1.2 m top coal caving interval when the coal seam thickness is greater than 4.0 m. These results provide a reference for the selection of a realistic top coal caving interval in thick coal seam caving mining.

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