Article
Energy & Fuels
Hao Xu, Yueping Qin, Fan Wu, Fengjie Zhang, Wei Liu, Jia Liu, Mingyan Guo
Summary: This study developed a mathematical model that integrates seepage and diffusion to describe the process of gas extraction from coal seams. The model was validated using a numerical simulator and the results indicate that the gas diffusion process in coal matrix is dominated by the free gas density gradient (FGDG). The gas permeability coefficient in fractures and the coal matrix radius have a significant contribution to the gas flow rate in different stages of extraction. The porosity of fractures is positively correlated with gas flow rate.
Article
Geosciences, Multidisciplinary
Qixian Li, Jiang Xu, Shoujian Peng, Fazhi Yan, Bin Zhou, Ende Han, Cheng Jiang
Summary: Coalbed methane co-production technique was explored in this study, revealing the pressure equilibrium and gas flow between different coal reservoirs. The study further demonstrated the dynamic supply state in coalbed methane production, enabling effective management and optimization of production efficiency.
NATURAL RESOURCES RESEARCH
(2021)
Article
Energy & Fuels
Chaojun Fan, Hao Sun, Zhijie Zhu, Mingkun Luo, Lijun Zhou, Lei Yang
Summary: The study investigates the strain evolution in coal seams during gas injection enhanced coalbed methane (ECBM) extraction using CO2 and N-2. The results show that N-2 has stronger fluidity in coal fractures and has a wider influencing range compared to CO2. Due to the greater affinity of CO2 to coal, it displaces gas more effectively and leads to migration towards the coal matrix. The methane content decreases by 24.3% in CO2-ECBM and by 13.8% in N-2-ECBM extraction compared to regular extraction.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2023)
Review
Energy & Fuels
Chao Xu, Tong Yang, Kai Wang, Qiang Fu, Shihao Ma
Summary: Coalbed methane is a low-carbon and clean energy source, but also a dangerous gas that threatens mine safety. Understanding the development of fractures and gas migration in the coal seam's overlying strata is essential for accurate extraction. Various methods, such as roadway, borehole drilling, and surface drilling, are used for gas extraction in the fractured zone.
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
Engineering, Chemical
Bin Zhou, Jiang Xu, Fazhi Yan, Shoujian Peng, Yabin Gao, Qixian Li, Liang Cheng
Summary: A custom-made large-scale test system was used to study the effects of gas pressure on coal-gas outburst (CGO) two-phase flow. Higher initial gas pressure led to higher solid-gas ratio, initial motion speed of CGO coal, and CGO intensity. Severe choking of two-phase flow and intermittent disturbances were observed, with a strong-disturbance zone developing in the middle of the roadway during the CGO process.
Article
Engineering, Environmental
Yong Li, Zhuangsen Wang, Shuheng Tang, Derek Elsworth
Summary: Differentiating between adsorbed and free methane in coal and shale is essential for gas recovery strategies and greenhouse gas control. The proposed method using nuclear magnetic resonance spectroscopy successfully determines adsorbed/free methane ratios and compares favorably with standard isothermal adsorption measurements.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Geosciences, Multidisciplinary
Jiaxin Zhu, Yongjiang Luo, Yunpei Liang, Xuewei Lv, Zhiqiang Zhao
Summary: In this study, a pressurized sampling method with frozen sealing was proposed to accurately estimate the coalbed methane content. The influences of various factors on gas loss rate and gas desorption characteristics were evaluated, and methods to reduce gas loss rate were suggested.
NATURAL RESOURCES RESEARCH
(2022)
Article
Environmental Sciences
Chengmin Wei, Chengwu Li, Qiusheng Ye, Zhenfei Li, Min Hao, Shanyang Wei
Summary: This research constructed a mathematical model to accurately predict the emission of coalbed methane and validated the model in the field. The study found that the new model had higher accuracy than the traditional model, leading to improved efficiency in controlling and utilizing coal mine gas disasters.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2023)
Article
Environmental Sciences
Chengmin Wei, Chengwu Li, Qiusheng Ye, Zhenfei Li, Min Hao, Shanyang Wei
Summary: In this research, a mathematical model for predicting gas emission from coalbed methane excavation workface was constructed, and a new model with higher accuracy and conciseness was proposed and validated. The study also analyzed the sensitivity of gas emission parameters and the participation ratio of gas emission sources.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2023)
Article
Energy & Fuels
Boris V. Malozyomov, Vladimir Ivanovich Golik, Vladimir Brigida, Vladislav V. Kukartsev, Yadviga A. Tynchenko, Andrey A. Boyko, Sergey V. Tynchenko
Summary: Decarbonization of the mining industry through energy generation closure, coal mine methane cogeneration, and internal consumption is crucial for sustainable development. However, deep underground mining faces challenges in utilizing man-made gas reservoirs. This study aims to improve drilling parameters for increasing methane production from unconventional coal-gas collectors. The innovative approach involves using established patterns of better natural stability of boreholes and optimizing them as spatial orientation parameters.
Article
Energy & Fuels
Yi Chen, Lei Zhou, Yu Peng, Xiangyan Ren
Summary: This study investigates the potential of directional wells with multiple hydraulic slots as a stimulation technology for deep coalbed methane extraction. The research finds that hydraulic slotting increases permeability and gas desorption, and directional wells with multiple slots optimize performance and enhance CBM recovery.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2023)
Review
Energy & Fuels
Wancheng Zhu, Shuyuan Liu, Xiufeng Zhang, Chenhui Wei
Summary: This paper provides a comprehensive review of the mechanisms and properties of gas adsorption in coal, the geomechanical behavior of coal, and the mechanisms of gas transport in coal. It also discusses several waterless fracturing techniques for improving coalbed permeability and identifies current knowledge and research gaps.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2022)
Article
Energy & Fuels
Jun Li, Qiming Huang, Gang Wang, Enmao Wang
Summary: Active water fracturing is a commonly used technology for enhanced coalbed methane extraction, but the residues may block pore spaces in coal samples. Research indicates that the effect of active water treatment on methane adsorption behavior varies significantly between different types of coal samples. Further optimization of the active water formulation could reduce damage to coal seams.
Article
Energy & Fuels
Shuji Tamamura, Takuma Murakami, Akio Ueno, Satoshi Tamazawa, Tamotsu Kiyama, Hidenori Inomata, Hiroyuki Matsumoto, Kagemi Uchida, Yoshiaki Suzuki, Jun Aizawa, Katsuhiko Kaneko
Summary: Isotopic analysis of rocks and sedimentary rocks from the Kushiro Coal Mine in Japan reveals the presence of thermogenic methane in some closed pores.
INTERNATIONAL JOURNAL OF COAL GEOLOGY
(2022)