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.

Numerical Simulation on Blasting Fume Diffusion in Blind Roadway with FLUENT

2013 ◽  
Vol 663 ◽  
pp. 655-660
Author(s):  
Zhen Hua Xie ◽  
Zheng Lan Yuan ◽  
Yu Zhang
Keyword(s):  
Numerical Simulation ◽  
Simulation Method ◽  
Mining Area ◽  
Computational Grids ◽  
Actual Situation ◽  
Forced Ventilation ◽  
Iron Mine ◽  
Effective Ventilation ◽  
Set Up ◽  
And Diffusion

Aiming at the generation of blasting fume in underground blind roadway, numerical simulation method was taken to obtain the diffusion law of the blasting fume. In accordance with the actual situation in Shachang mining area of Shouyun iron mine, the physical model and mathematical model were set up, computational grids were divided, and the boundary condition was established. The diffusion law of blasting fume and the completion time under different explosives dosage were simulated by Fluent. The laws of blasting fume diffusion and diffusion time changing with the amount of explosive in local fan forced ventilation were obtained. The results can provide a theoretical basis for the research of a reasonable and effective ventilation manner of blind roadway.

scholarly journals Model of Prediction of Gas Emission based on Gas Content Uncertainty in Coal Mine using Geostatistical Simulation and Monte Carlo Method

2021 ◽  
Author(s):  
Shokofe Rahimi ◽  
Majid Ataee-pour ◽  
Hasan Madani
Keyword(s):  
Monte Carlo ◽  
Coal Seam ◽  
Ventilation System ◽  
Prediction Method ◽  
Simulation Method ◽  
Worker Safety ◽  
Gas Content ◽  
Geostatistical Simulation ◽  
Gas Emission ◽  
Factors Affecting

Abstract It is very difficult to predict the emission of coal gas before the extraction, because it depends on various geological, geographical and operational factors. Gas content is a very important parameter for assessing gas emission in the coal seam during and after the extraction. Large amounts of gas released during the mining cause concern about adequate airflow for the ventilation and worker safety. Hence, the performance of the ventilation system is very important in an underground mine. In this paper, the gas content uncertainty in a coal seam is first investigated using the central data of 64 exploratory boreholes. After identifying the important coal seams in terms of gas emission, the variogram modeling for gas content was performed to define the distribution. Consecutive simulations were run for the random evaluation of gas content. Then, a method was proposed to predict gas emission based on the Monte Carlo random simulation method. In order to improve the reliability and precision of gas emission prediction, various factors affecting the gas emission were investigated and the main factors determining the gas emission were identified based on a sensitivity analysis on the mine data. This method produced relative and average errors of 2% and 0.57%, respectively. The results showed that the proposed model is accurate enough to determine the amount of emitted gas and ventilation. In addition, the predicted value was basically consistent with the actual value and the gas emission prediction method based on the uncertainty theory is reliable.

Gas Control Technology of Fully Mechanized Caving Face of Hard Desorbing Coal Seam

2013 ◽  
Vol 718-720 ◽  
pp. 1335-1340
Author(s):  
Gang Wang ◽  
Hai Yang Wang ◽  
Xin Hua Zhang
Keyword(s):  
Coal Seam ◽  
Efficient Production ◽  
Control Technology ◽  
Actual Situation ◽  
Coal Face ◽  
Gas Emission ◽  
Investment Cost ◽  
Residual Gas ◽  
Gas Control ◽  
Residual Coal

Basing on the problems of residual coal in goaf in fully mechanized caving face in hard desorbing coal seam, high content of residual gas, large gas emission, serious gas overrun in return airflow corner and vitiated air, combing the actual situation in 3-219 fully mechanized caving face, the paper has adopted adjacent goaf drainage, drainage in gas drainage technology, formed a low investment cost and effective gas control technology and ensured the safe and efficient production in coal face and has a certain reference to control gas of fully mechanized caving face in hard desorbing coal seam.

Features of Jianshanchong Klippe and its Control to Gas Geology at Qingshan Coal Mine, Jiangxi Province

2012 ◽  
Vol 164 ◽  
pp. 501-505
Author(s):  
Zhi Gen Zhao ◽  
Jia Chen ◽  
Jia Ping Yan
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Emission Rate ◽  
Coal And Gas Outburst ◽  
Jiangxi Province ◽  
Coal Seams ◽  
Gas Emission ◽  
Gas Outburst ◽  
Transverse Profile ◽  
Tectonic Coal

The coal and gas outburst is serious at Qingshan Coal Mine of Jiangxi Province, so it is of significance to research the features of Jianshanchong klippe and its control to gas geology. The research reveals that: Jianshanchong klippe is distributed from the east boundary of Qingshan Coal Mine to No. 45 Exploration Line, its transverse profile is like a funnel while its longitudinal profile is like a wedge, northwest side of the klippe is thicker and deeper while southeast side is thinner and more shallow. Because of the cover and insert of Jianshanchong klippe, the structure of coal-bearing strata is more complex, some secondary folds are formed, and also, the coal seam is changed greatly, the tectonic coal is well developed and the coal seam is suddenly thickening or thinning. Due to the effect of Jianshanchong klippe, the coal and gas outbursts occur in the area of secondary folds, thicker coal seams or tectonic coals. Concerning the prediction of gas geology in deep area, in view of the facts including simpler structure, stable coal seam and decreased thickness, the gas emission rate and the coal and gas outburst will decrease in Fifth and Sixth Mining Level than that in Second and Third Mining Level

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 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.

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