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Full-Text Articles in Engineering
An Experimental Study Of Factors Influencing Gas Seepage In Confined Broken Anthracite, Li Zhen, Yu Yirui, Wang Hongwei, Feng Guorui, He Fulian, Wang Dezhang, Zhou Jinhui, Liu Luyan, Han Xinlei
An Experimental Study Of Factors Influencing Gas Seepage In Confined Broken Anthracite, Li Zhen, Yu Yirui, Wang Hongwei, Feng Guorui, He Fulian, Wang Dezhang, Zhou Jinhui, Liu Luyan, Han Xinlei
Coal Geology & Exploration
The void structure evolution of broken coals in a caving zone directly affects the gas seepage characteristics of the zone, further influencing the gas migration and enrichment patterns in abandoned coal mine goaves. With the second generation of compaction-seepage-CT scanning experimental system for broken coals independently designed and developed, this study performed 162 sets of permeability experiments on broken anthracite samples with five particle size ranges under varying gas pressures, axial stresses, and void fractions. Key findings are as follows: (1) When gas migrated in broken anthracite, its pressure and flow rate kept dynamically changing until the adsorption equilibrium was …
Fractal Theory-Based Permeability Model Of Fracture Networks In Coals, Xia Binwei, Liao Chuanbin, Luo Yafei, Ji Kainan
Fractal Theory-Based Permeability Model Of Fracture Networks In Coals, Xia Binwei, Liao Chuanbin, Luo Yafei, Ji Kainan
Coal Geology & Exploration
Fractures in coal reservoirs, which act as the major seepage pathways for coalbed methane (CBM), determine the permeability and CBM productivity of coal reservoirs. Research on the relationships between fracture structures and reservoir permeability is of great theoretical and practical significance for the accurate prediction of CBM productivity. Based on the classical cubic law-based permeability model, as well as the fractal theory, fracture network structures, and effective stress, this study built a permeability model containing complex bending fractures, which was then combined with the S & D (Shi-Durucan) model to build the permeability model of fractured coals under the action …
Co2-Ecbm Simulation Study Considering Klinkenberg Factor State, Sa Zhanyou, Wu Jingbo, Yang Yongliang, Zhang Xin, Lu Shouqing, Liu Jie, Wang Hao
Co2-Ecbm Simulation Study Considering Klinkenberg Factor State, Sa Zhanyou, Wu Jingbo, Yang Yongliang, Zhang Xin, Lu Shouqing, Liu Jie, Wang Hao
Coal Geology & Exploration
In order to explore the role of Klinkenberg effect and Klinkenberg factor in different states in the process of CO2-Enhanced Coal Bed Methane (CO2-ECBM), the effects of Klinkenberg factor of zero, fixed Klinkenberg factor and dynamic Klinkenberg factor on CO2-ECBM were simulated and analyzed by COMSOL finite element software. The dynamic changes of CH4 and CO2 pressure with this factor were studied, and the CH4 gas production was compared with the engineering practice. The results show that the effective permeability of CH4 and CO2 increases slowly at first, then …
Numerical Simulation Of Co2 Storage In Bedded Salt Rock Storage Cavern In Subei Basin, Zong Shi, Liu Shiqi, Xu Hui, Wang Wenkai, Cao Bo, Huang Fansheng
Numerical Simulation Of Co2 Storage In Bedded Salt Rock Storage Cavern In Subei Basin, Zong Shi, Liu Shiqi, Xu Hui, Wang Wenkai, Cao Bo, Huang Fansheng
Coal Geology & Exploration
Underground salt cavern is an effective geological body for CO2 storage. The leakage of CO2 along the weak interlayer of salt rock and the interface of salt layer and interlayer is the key to restrict the safe storage of CO2 in underground salt cavern. A fluid-solid coupling mathematical model of CO2 storage in bedded salt cavern gas storage was established based on the CO2 salt cavern storage in Jintan area of Subei basin. On this basis, the leakage and migration law of CO2 in salt rock and mudstone interlayer, as well as its influence …
Stress Sensitivity Characteristics And Control Mechanism Of Different Coal Rank Reservoirs, Sun Fenjin, Yang Jiaosheng, Wang Meizhu, Sun Bin, Zhang Jidong, Zhao Yang, Deng Ze
Stress Sensitivity Characteristics And Control Mechanism Of Different Coal Rank Reservoirs, Sun Fenjin, Yang Jiaosheng, Wang Meizhu, Sun Bin, Zhang Jidong, Zhao Yang, Deng Ze
Coal Geology & Exploration
The stress sensitivity of coal reservoir reduces the permeability, which in turn affects the productivity of coalbed methane (CBM)wells. So how to reduce this effect from stress sensitivity deserves further study in the CBM wells drainage process. To clarify the stress sensitivity characteristic and differences of different rank coal reservoirs, coal samples collected respectively from Fanzhuang block (high rank coal), Baode block (medium rank coal) and Erlian Basin (low rank lignite) were employed in this study. The stress sensitivity experiments of different rank coal samples were systematically carried out during loading and unloading process. Meanwhile, stress sensitivity mechanism was analyzed. …
Numerical Simulation Of Gas Production For Multilayer Drainage Coalbed Methane Vertical Wells In Southern Qinshui Basin, Liu Shiqi, Fang Huihuang, Sang Shuxun, Hu Qiujia, Duan Weiying, Jia Huimin, Mao Chonghao
Numerical Simulation Of Gas Production For Multilayer Drainage Coalbed Methane Vertical Wells In Southern Qinshui Basin, Liu Shiqi, Fang Huihuang, Sang Shuxun, Hu Qiujia, Duan Weiying, Jia Huimin, Mao Chonghao
Coal Geology & Exploration
With the development of CBM (coalbed methane) exploitation, multilayer drainage of the CBM well has received wide attention. The production control technology is the key to ensure high and stable gas production of CBM well multilayer drainage. However, the complex geological conditions of multiple coal seams increase the difficulty of production control of multilayer drainage. Numerical simulation technology is an effective method to study the production control technology of CBM well multilayer drainage. The scientific and reliable simulation results can provide a basis for production control. In this study, considering the influence of temperature effect, shrinkage effect of coal matrix, …
Molecular Simulation Of The Effect Of Co2/N2 Binary Gas On Methane Adsorption In Coal, Sun Zhixue, Min Cheng, Zhang Wanlu, Jiang Yongping, Yu Xuefeng, Cui Bin
Molecular Simulation Of The Effect Of Co2/N2 Binary Gas On Methane Adsorption In Coal, Sun Zhixue, Min Cheng, Zhang Wanlu, Jiang Yongping, Yu Xuefeng, Cui Bin
Coal Geology & Exploration
The binary gas flooding technology (CO2/N2-ECBM) has become an important means of increasing the production of coalbed methane(CBM). It is of great significance to clarify the CO2/N2 competitive adsorption law in coal seams and its influence on the physical properties of coal seams. The molecular simulation software Materials Studio was used to establish a coal molecular model according to the actual temperature and pressure of the CBM block in Yanchuannan. On the basis of the Grand Canonical Monte Carlo(GCMC) method, the influence of each injection stage in the technology of CO2/N …
Plastic Deformation-Based Constitutive Relation Of Coal Damage And Permeability Model, Wu Xuehai, Li Bobo, Wang Xin, Gao Zheng, Li Jianhua, Xu Jiang
Plastic Deformation-Based Constitutive Relation Of Coal Damage And Permeability Model, Wu Xuehai, Li Bobo, Wang Xin, Gao Zheng, Li Jianhua, Xu Jiang
Coal Geology & Exploration
Coal and gas outburst induced by mining disturbance is one of the main gas dynamic disasters in coal mine production. In order to systematically explore the evolution characteristics of coal damage and the law of gas seepage under mining disturbance, the whole stress strain–seepage experiment under different gas pressures was carried out. The generalized Hooke's law was modified by considering the effects of gas adsorption and thermal expansion, the plastic deformation-based constitutive relation of coal damage was established, and the piecewise permeability model considering the damage was further constructed. The results shown that the coal permeability can be divided into …
Slippage Effect And The Seepage Mechanism Considering The Compaction And Embedding Action Of Proppant, Cheng Qiaoyun, Li Bobo, Li Jianhua, Gao Zheng, Wang Bin
Slippage Effect And The Seepage Mechanism Considering The Compaction And Embedding Action Of Proppant, Cheng Qiaoyun, Li Bobo, Li Jianhua, Gao Zheng, Wang Bin
Coal Geology & Exploration
Hydraulic fracturing technology is an effective method to improve the efficiency of coalbed methane drainage, but the universal embedding of proppant under stress will change the width of the fractures, which will affect the gas slippage effect and the permeability mechanism. In order to explore the gas slippage effect and coal seepage law under the background of hydraulic fracturing, the Hertzian contact theory is used to quantify the embedding depth of proppant, and the gas slippage coefficient calculation equation and permeability model of the combined effect of proppant and effective stress are constructed. The results show that under different gas …
Experimental Study On The Influence Of Coal-Based Co2 Geological Storage On Roof Fracture Conductivity, Zhu Shiliang, Shao Liwei, Zhou Xiaozhi, Cao Yutong, Zhang Kun, Wang Jiandong
Experimental Study On The Influence Of Coal-Based Co2 Geological Storage On Roof Fracture Conductivity, Zhu Shiliang, Shao Liwei, Zhou Xiaozhi, Cao Yutong, Zhang Kun, Wang Jiandong
Coal Geology & Exploration
Coal-based CO2 geological storage is an important way to reduce greenhouse gas emissions, but there is also a safety risk of underground CO2 leakage. In order to evaluate the safety of coal-based CO2 geological storage, the roof samples of No.3 coal seam in Hudi Coal Mine, southern Qinshui Basin were collected, and the changes of artificial fracture morphology, whole rock mineral composition and CO2 conductivity of columnar samples in "CO2-H2O-Rock" reaction were studied by simulation experiments. The results show that calcite vein dissolution, secondary mineral filling and external effective stress jointly affect …
Application Of Broadband And Wide Azimuth Processing Technology In Full Digital High Density Seismic Exploration In Huaibei Mining Area, Yang Guangming, Jin Xueliang, Zhang Xianxu, Zhi Min, Shan Rui
Application Of Broadband And Wide Azimuth Processing Technology In Full Digital High Density Seismic Exploration In Huaibei Mining Area, Yang Guangming, Jin Xueliang, Zhang Xianxu, Zhi Min, Shan Rui
Coal Geology & Exploration
During coalbed methane well drilling, the drilling fluid contaminates and blocks the pores and fractures of coal seam. In order to find out the difference of pollution degree of drilling fluid coal and the contribution rate of the pores and fractures of different scale to permeability, the coal of Changping mine was taken as the research object, the scanning electron microscopy(SEM) and the Image Pro Plus(IPP) processing technology were used, the parameters such as the average length, the average width, the total area and the total perimeter of the fractures of different scales in coal before and after contamination were …
Quantitative Evaluation Of The Contamination Degree Of The Drilling Fluid For Fractures Of Different Scale In Coal, Zhang Jingshuo, Ni Xiaoming, Li Yang, Li Zongyuan, Cao Yunxing
Quantitative Evaluation Of The Contamination Degree Of The Drilling Fluid For Fractures Of Different Scale In Coal, Zhang Jingshuo, Ni Xiaoming, Li Yang, Li Zongyuan, Cao Yunxing
Coal Geology & Exploration
During coalbed methane well drilling, the drilling fluid contaminates and blocks the pores and fractures of coal seam. In order to find out the difference of pollution degree of drilling fluid coal and the contribution rate of the pores and fractures of different scale to permeability, the coal of Changping mine was taken as the research object, the scanning electron microscopy(SEM) and the Image Pro Plus(IPP) processing technology were used, the parameters such as the average length, the average width, the total area and the total perimeter of the fractures of different scales in coal before and after contamination were …
Evaluation Of Coalbed Methane Drainage Effect For Multi-Target Seams In Jincheng Region, Yang Jianchao, Li Guihong, Liu Yuhui, Li Guofu, Wang Chaoshuai, Sun Tianyu
Evaluation Of Coalbed Methane Drainage Effect For Multi-Target Seams In Jincheng Region, Yang Jianchao, Li Guihong, Liu Yuhui, Li Guofu, Wang Chaoshuai, Sun Tianyu
Coal Geology & Exploration
The study of the multi-target seams drainage effect on coalbed methane wells has great value, including coal safe mining, underground gas control, determination of development technical indicators, single well production, rational division of development layer, efficient development of coalbed methane, and development of medium and long-term coalbed methane development planning. Taking Chengzhuang mine of Jincheng as an example, the sampling data of the extraction effect in the middle and late stages of development are compared with the original gas content of the adjacent wells to evaluate the extraction effect, and the main control factors affecting the drainage effect are analyzed …
Simulation Of Seepage Water Inrush Mechanism And Strength Controlling Factors Of Collapse Column, Huo Bingjie, Xie Zhenhua, Fan Zhanglei, Jing Xuedong
Simulation Of Seepage Water Inrush Mechanism And Strength Controlling Factors Of Collapse Column, Huo Bingjie, Xie Zhenhua, Fan Zhanglei, Jing Xuedong
Coal Geology & Exploration
In order to study the mechanism and main control factors of seepage water inrush in roadway affected by collapse columns, Darcy, Brinkman and N-S equations were used to describe the linkage system of flow field in aquifer, collapse column and water inrush roadway. Variables such as different parameters and different boundaries were selected to analyze the main factors influencing the seepage water inrush intensity of collapse columns. The results show that under the conditions of constant pressure and flow, the increase of aquifer permeability will lead to the increase of flow velocity in an area where the aquifer meets the …
Fractal Theory-Based Investigation Of The Optimal Interval Of Minimum Pore Radius Of Sandstone, Xu Lulu, Dong Shuning, Dai Zhenxue, Xu Bin, Yin Shangxian, Zhou Yan, Chen Junjun
Fractal Theory-Based Investigation Of The Optimal Interval Of Minimum Pore Radius Of Sandstone, Xu Lulu, Dong Shuning, Dai Zhenxue, Xu Bin, Yin Shangxian, Zhou Yan, Chen Junjun
Coal Geology & Exploration
Permeability is a main parameter for evaluation of water conductivity of porous media, and it is a macroscopic feature of micro-pore structure of water-conducting media. To obtain the geometry parameters of microscopic pores, we performed scanning electron microscopy(SEM) on sandstone samples. The image processing techniques were also applied in calculation of different statistical parameters(e.g., fractal dimensions) and geometrical parameters. Then, fractal theory was introduced to investigate the influence of micro pore structure on permeability. At the same time, the minimum pore radius rmin interval acting on the seepage was obtained by the measured permeability values. This interval can be …
Fractal Characteristics Of Pores And Microfractures Of Coals With Different Structure And Their Effect On Permeability, Ye Zhenni, Hou Enke, Duan Zhonghui, Wen Qiang, Huang Meitao, He Dan
Fractal Characteristics Of Pores And Microfractures Of Coals With Different Structure And Their Effect On Permeability, Ye Zhenni, Hou Enke, Duan Zhonghui, Wen Qiang, Huang Meitao, He Dan
Coal Geology & Exploration
The characteristics of pores and fractures in coal are the basis to study permeability. In this study, the micro-pores and fractures of coal samples with different structure taken from Guojiahe coal mine were analyzed using mercury injection experiment and scanning electron microscope. The micro-pores and fractures of intact coal and cataclastic coal samples were quantitatively analyzed by using Menger sponge and box-counting dimension. The comprehensive fractal dimension was calculated by pore volume weights. Based on fractal theory, the relationship between fractal dimension of coal samples and coal permeability have been discussed. The results show that brittle deformation adds complexity of …
Effect Of Nmr Technology-Based Ultrasonic Frequency On Stimulated Cracking Of Coal, Ma Huiteng, Zhai Cheng, Xu Jizhao, Sun Yong
Effect Of Nmr Technology-Based Ultrasonic Frequency On Stimulated Cracking Of Coal, Ma Huiteng, Zhai Cheng, Xu Jizhao, Sun Yong
Coal Geology & Exploration
In order to further study the effect of ultrasonic frequency on the stimulated cracking effect of coal, the paper conducted the crack experiment on the original coal samples by using the ultrasonic generation meter, and measured the coal by using the NMR equipment through analyzing the T2 curve, the changes of pore structure before and after coal sample cracking were deeply studied. The results show that the pore structure of coal can be effectively improved by the ultrasonic wave. After the crack induced by the ultrasonic wave, the pore quantity inside the coal increased and the total porosity, effective …
Model Of Gas-Bearing Coal Permeability Prediction Based On Apso-Wls-Svm, Mao Zhiyong, Huang Chunjuan, Lu Shichang, Han Rongyue
Model Of Gas-Bearing Coal Permeability Prediction Based On Apso-Wls-Svm, Mao Zhiyong, Huang Chunjuan, Lu Shichang, Han Rongyue
Coal Geology & Exploration
In order to predict gas-bearing coal permeability accurately and prevent gas accidents effectively, a weighted least square support vector machine(WLS-SVM) algorithm based on Adaptive Particle Swarm Optimization(APSO) is proposed. Based on the related theory and literature research on gas-bearing coal permeability, the effective stress, gas pressure, temperature and compressive strength were selected as the main characteristic indexes. The APSO algorithm was used to optimize the combination parameters(C, σ) of the WLS-SVM model and APSO-WLS-SVM gas-bearing coal permeability prediction model was established. According to the field data, 40 sets of data were used as training samples and the remaining …