Article
Geosciences, Multidisciplinary
Taiyuan Zhang, Shu Tao, Dazhen Tang, Shuling Tang, Hao Xu, Aobo Zhang, Yifan Pu, Yingying Liu, Qiang Yang
Summary: A laboratory method was established to evaluate the influence of dip angle on coal permeability. It was found that with increasing dip angle, the permeability of coal samples showed a decreasing trend. Numerical simulations confirmed this phenomenon, providing insights into the anisotropic behavior of coal samples under different dip angles.
NATURAL RESOURCES RESEARCH
(2021)
Article
Geosciences, Multidisciplinary
Taiyuan Zhang, Shuling Tang, Dazhen Tang, Shu Tao, Aobo Zhang, Yifan Pu
Summary: The anisotropy of coal pores and fractures (APF) has a significant impact on coal reservoirs, especially in high-dip coal seams. A low-field nuclear magnetic resonance (NMR) test can be used to detect the pore size distribution under different confining pressures and express the evolution of APF with stress. Pressurized NMR tests revealed that the majority of the micropores had geometric spindles parallel to the bedding plane, and the seepage fractures were mostly occupied by the cleat system perpendicular to the bedding plane. The compressibility of the fractures was related to the normal stress received.
NATURAL RESOURCES RESEARCH
(2023)
Article
Energy & Fuels
Pengwei Mou, Jienan Pan, Kai Wang, Jiang Wei, Yanhui Yang, Xianglong Wang
Summary: Hydraulic fracturing significantly increases the permeability of coal microfractures by expanding existing fractures rather than inducing new ones. The impact of hydraulic fracturing on microfractures is influenced by the heterogeneity of coal samples and differences in in-situ stress.
Article
Construction & Building Technology
Zhiliu Wang, Bo Liu, Yanhui Han, Zhaoyang Li, Yingjie Cao, Fuzhou Qi
Summary: By analyzing the fracture zone and conducting modeling experiments, the layout parameters for the gas drainage roadway (GDR) were determined. The recommended optimal height and horizontal distance can effectively improve the gas drainage effect in mining operations.
ADVANCES IN CIVIL ENGINEERING
(2021)
Article
Geosciences, Multidisciplinary
Yubing Liu, Maxim Lebedev, Yihuai Zhang, Enyuan Wang, Wenpu Li, Jiabin Liang, Runhua Feng, Rupeng Ma
Summary: Cleat and permeability in coal play a crucial role in enhanced coalbed methane production and CO2 geo-sequestration. This study used a novel in situ micro-CT core flooding apparatus to observe the closure of micro-cleats in small anthracite coal at different CO2 injection pressures. The results showed that the mean aperture size of the micro-cleat increased and then decreased with increasing injection pressures, with a higher rebound in mean aperture size parallel to cleat directions. The permeability decreased drastically initially and then slowly with an increase in saturation time.
NATURAL RESOURCES RESEARCH
(2022)
Article
Energy & Fuels
Xiangliang Zhang, Baiquan Lin, Jian Shen
Summary: The study found that plasma based on the principle of electrical breakdown can enhance the permeability of loaded coal, with the formation of interconnected fracture networks significantly increasing coal permeability. The changes in flow state from Darcy flow to non-Darcy flow after breakdown also facilitate fluid migration in coal.
Article
Thermodynamics
Zhengdong Liu, Xiaoson Lin, Wancheng Zhu, Ze Hu, Congmeng Hao, Weiwei Su, Gang Bai
Summary: Permeability rebound and recovery during the permeability evolution process is an important behavior affected by temperature and reservoir pressure changes. A binary gas permeability evolution model was used to study the dynamic evolution of various parameters during CO2 injection into CH4-containing coal at different temperatures. The study found that permeability shows a complex evolution over time, with the time required for rebound and recovery increasing with temperature. Monitoring gas migration patterns revealed that CO2 flow rate and cumulative storage volume decrease with increased rebound and recovery time. The study proposed using the stage-pressure injection method to increase CO2 injection effect.
Article
Geosciences, Multidisciplinary
Yixin Lu, Zhaoping Meng, Xuefeng Su, Yina Yu
Summary: This study reveals the evolution of coal sample permeability during fracturing and establishes the relationship between coal sample fracture morphology and permeability. The results provide data support for the reformation of hydraulic fracturing in coalbed methane wells.
NATURAL RESOURCES RESEARCH
(2022)
Article
Energy & Fuels
Ming Yuan, Shuaifeng Lyu, Shengwei Wang, Fengyin Xu, Xia Yan
Summary: Understanding the distribution of fracture systems in CBM reservoirs is crucial for enhancing coalbed methane development. This study investigates the impact of different coal macrolithotypes on coal fracture development through mechanical property analysis and petrography and palynology tests. The results reveal a relationship between coal facies and fracture system characteristics, providing insights for predicting fracture system development in ultra-thick coal seams.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Energy & Fuels
Yafei Luo, Binwei Xia, Honglian Li, Huarui Hu, Mingyang Wu, Kainan Ji
Summary: Coal is a dual-porosity medium with internal pore-fracture structure, and understanding the relationship between permeability and pore-fracture structure characteristics is crucial for predicting coalbed methane productivity accurately. A new fractal permeability model of dual-porosity media embedded with natural tortuous fractures has been established in this study, showing improved accuracy in predicting coal seam permeability compared to traditional models. The numerical simulation results demonstrate strong power-law relationships between coal permeability and fracture geometric characteristic parameters, validating the proposed model's accuracy.
Article
Energy & Fuels
Jianwei Tian, Jishan Liu, Derek Elsworth, Yee-Kwong Leong, Wai Li
Summary: In this study, a dual-fractal permeability model was proposed to investigate the impacts of coal internal structure on permeability. The model considers the effects of pore-fracture size distribution and effective stress, and incorporates multiple flow mechanisms.
Article
Energy & Fuels
Jiang Liu, Yili Kang, Mingjun Chen, Lijun You, Tingshan Zhang, Xinping Gao, Zhangxing Chen
Summary: Enhancing coal permeability through formation heat treatment is an effective method for coalbed methane exploitation. The process involves removing residual water and inducing cracks in the coal structure, significantly increasing permeability. Additionally, the stimulation mechanisms consist of alleviating aqueous phase trapping, weakening coal mechanical properties, and inducing coal fracture to produce more gas flow channels.
Article
Chemistry, Multidisciplinary
Jiayong Zhang, Yongzhen Niu, Jian Chen, Yanlei Guo, Liwen Guo
Summary: This study focuses on solving the problem of low permeability and difficult extraction of coalbed methane from deep coal seams. A new method of directional hydraulic splitting for enhancing the extraction of deep coalbed methane is proposed by combining hydraulic splitting technology and directional drilling technology. The numerical simulation results reveal that using a directional splitting angle can increase the damaged area of the coal seam and enhance the development length of fractures, thus improving the extraction efficiency and reducing the mining risk.
APPLIED SCIENCES-BASEL
(2022)
Article
Chemistry, Multidisciplinary
Yanlei Guo, Haibin Liu, Xu Zhou, Jian Chen, Liwen Guo
Summary: The XGBoost-GR-stacking gas outburst early warning model proposed in this article demonstrates high accuracy and practical performance, making it suitable for gas outburst risk warning in mining safety. The model is based on gas outburst data from 26 mines and establishes a data generation model based on XGBoost. Grey correlation analysis is used to select the main control factor groups based on the sorting of correlation degrees. Comparing the actual and predicted values for each model, the stacking fusion model achieves the highest accuracy in gas outburst prediction and the best model fitting effect.
APPLIED SCIENCES-BASEL
(2023)
Article
Energy & Fuels
Bo Wang, Yanting Wu, Guofu Li, Jiaosheng Yang, Yang Zhao, Meizhu Wang, Jian Zhou, Tong Wu, Zhejun Pan
Summary: The study revealed that mineral fillings in coal beds have a significant impact on the permeability and production of coalbed methane (CBM) in China, especially in the fracture system. The influence of mineral fillings on permeability and fracture compressibility is complex, and the strong swelling strain anisotropy and low Poisson's ratio associated with mineral fillings are also noteworthy.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Geochemistry & Geophysics
Hao Han, Shun Liang, Yaowu Liang, Xuehai Fu, Junqiang Kang, Liqiang Yu, Chuanjin Tang
Article
Chemistry, Multidisciplinary
Liu Zhu, Qiangling Yao, Qiang Xu, Liqiang Yu, Qundi Qu
Summary: In this study, the support of soft rock roadways in the Jiebangou coal mine was investigated. Through field investigation and numerical calculations, the deformation and damage characteristics of the soft rock roadway and its causes were analyzed. A support technology system of 'strengthening support for weak structural parts' was proposed, effectively controlling the deformation, damage, and instability of the roadway and surrounding rock.
APPLIED SCIENCES-BASEL
(2022)
Article
Geochemistry & Geophysics
Furong Wang, Chengle Wu, Qiangling Yao, Xuehua Li, Shengyan Chen, Yinghu Li, Haitao Li, Guiwei Zhu
Summary: In this study, the mechanisms and control of weakened water-rich roadway roof slabs were investigated. Through field measurements, the spatial and temporal evolution law of rock deformation and damage were determined. The research proposed a technical approach for controlling the stability of the surrounding rock by adjusting the form of the roadway section and optimizing the support parameters. The results were applied in the field and showed effective control of the deformation of the water-rich roadway's surrounding rock.
Article
Geochemistry & Geophysics
Hongye Luo, Shun Liang, Qiangling Yao, Yisong Hao, Xuehua Li, Furong Wang, Xiaoyu Chen, Miao Yang
Summary: The study aims to address the issue of thick and hard gangue layers in fully mechanized top-coal caving mining of ultra-thick coal seams. Through theoretical analysis, numerical simulation, and field practice, a method of pre-fracturing and weakening high-level thick and hard gangue layers using hydraulic fracturing technology is proposed. The results show that this technology can improve the recovery rate and overall fragmentation.
Article
Geochemistry & Geophysics
Weinan Wang, Qiangling Yao, Qiang Xu, Xiaoyu Chen, Hengyi Liu, Xuehua Li
Summary: This study investigates the evolution of voids in a cracked rock mass under mining disturbance and the compaction and void deformation characteristics of caving gangue under the effect of water-rock interaction. Experimental and theoretical analysis reveal that the fractal dimensions of rock mass voids and physical properties of gangue are influenced by the mining process and immersion time.
Editorial Material
Energy & Fuels
Qiangling Yao, Liqiang Yu
Article
Energy & Fuels
Yang Wu, Qiangling Yao, Baoyang Wu, Hongxin Xie, Liqiang Yu, Yinghu Li, Lujun Wang
Summary: In this study, the coal pillar dam body of the 2(2) layers of coal in the Shangwan Coal Mine was investigated. The internal failure mechanism of coal water action was analyzed using acoustic emission detection technology and energy dissipation analysis method. The research findings can be applied to the long-term sustainability assessment of coal column dams in underground reservoirs and provide valuable insights for the design of water-bearing coal column dams under similar engineering conditions.
Article
Environmental Sciences
Liu Zhu, Qiangling Yao, Qiang Xu, Yinghu Li, Xuehua Li
Summary: Coal mining has resulted in groundwater pollution and loss. This study investigates the use of mined areas for storing and purifying mine water, proving it to be a low-cost and environmentally friendly mining method. Adsorption experiments conducted using roof rocks from the Lingxin coal mine show that gangue can stabilize the pH value of mine water and has an adsorption rate of 3-5%. The results support further research on using gangue for water purification in mines and promoting the recycling of highly mineralized water.
Article
Environmental Sciences
Zhuolin Shi, Qiangling Yao, Weinan Wang, Fengsheng Su, Xuehua Li, Liu Zhu, Chengle Wu
Summary: Percolation experiments were conducted on coal samples to study the effects of fracture length and inclination angle on seepage. A three-dimensional seepage model was constructed to investigate the seepage pattern. The results showed that permeability increases non-linearly with fracture length for small fractures, while it decreases and then increases for large fractures. The study provides insights into the mechanism of fracture seepage under different stress conditions.
Article
Green & Sustainable Science & Technology
Hongxin Xie, Qiangling Yao, Liqiang Yu, Changhao Shan
Summary: This study investigates the damage mechanism and characteristics of coal samples with different moisture content and wetting-drying cycles under cyclic loading. The results show that the increase in moisture content and wetting-drying cycles leads to significant changes in the performance and damage characteristics of the coal samples under cyclic stress.