Article
Energy & Fuels
Jiexin Lu, Chunshan Zheng, Wuche Liu, He Li, Shiliang Shi, Yi Lu, Qing Ye, Yuannan Zheng
Summary: Microwave-assisted acidification is a promising method for enhancing CBM recovery by improving pore structure and fracture connectivity in coal. It greatly increases pore volume, length, and width of fractures compared to microwave heating or acidification alone. This study demonstrates the significant potential of microwave-assisted acidification for CBM production.
Article
Energy & Fuels
Jiangang Ren, Zhimin Song, Bing Li, Jianbao Liu, Runsheng Lv, Gaofeng Liu
Summary: The study focuses on the characteristics and evolution mechanisms of coal pore structure, revealing that pore size decreases and the increase of closed pores are controlled by tectonic stress during metamorphism and deformation processes.
Article
Environmental Sciences
Xiao Feng, Panpan Zhang, Zizhong Zhang, Hongguang Guo, Zhigang Li, Zaixing Huang, Michael Urynowicz, Muhammad Ishtiaq Ali
Summary: Biomethane generation by coal degradation can increase coalbed methane (CBM) reserves and affect the pore structure of coal. The biodegradation of bituminous coal and lignite to produce methane was performed to analyze the effect on coal pore development. The results showed that biodegradation decreased the specific surface area and pore volume of micropores and increased the fractal dimension. Various organics were generated, with a portion released into the culture solution and the majority remaining in residual coal. The effect of biodegradation on pore development depended on the combined action of methane production and organics retention in coal.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2023)
Article
Energy & Fuels
Gangtao Mao, Zhiping Li, Fengpeng Lai, Hexin Wei
Summary: This study investigates the effects of organic solvents on the pore structure and fluid distribution in CBM reservoirs, finding that ethylene glycol ether and ethanol can effectively enhance pore structure parameters in coal samples, with ethylene glycol ether consistently reducing irreducible water saturation in samples. Considering the alterations in pore structure, ethylene glycol ether is shown to be more preferable for enhancing recovery from CBM reservoirs compared to ethanol.
Article
Energy & Fuels
Ming Cheng, Xuehai Fu, Junqiang Kang, Zhongbin Tian, Youyi Shen
Summary: After coal mines are abandoned, a large amount of coalbed methane resources remain in the coal strata. Fracturing significantly alters the pore structure of coal/rock, impacting the development and migration of CBM. This study quantifies pore-fracture strain and proposes a plastic deformation-based model to discuss the influence of coal/rock fracture on CBM migration. The results show that pore volumes decrease post-fracture, with coal compression being more significant, and pore compression reduces the diffusion path for CBM migration.
Article
Engineering, Environmental
Huihu Liu, Junlin Liu, Sheng Xue, Kun Zhang, Hongje Xu, Huihuang Fang, Jinlong Jia
Summary: This study investigated the high-pressure adsorption-desorption of super-critical CO2 and CH4 in low permeability coal, revealing the factors affecting gas adsorption capacity and the hysteresis of adsorbed gases.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2022)
Article
Energy & Fuels
Xiaoxue Liao, Liang Wang, Jintuo Zhu, Peng Chu, Qingquan Liu, Tao Yang
Summary: Gas adsorption capacity and ash content have an impact on the wettability of coal, with coal becoming less hydrophilic with increasing hardness. The pore characteristics significantly influence wettability, with coal showing better wettability when there is good pore connectivity.
Article
Energy & Fuels
Gang Bai, Zhongjie Zhou, Xueming Li, Yuantao Cheng, Kun Hu, Ying Chen, Xihua Zhou
Summary: This study investigates the CO2 displacement of CH4 in different coal samples using the LF-NMR technique and establishes a quantitative model. The results show that the pore and fissure structures differ among different coal samples, and CO2 injection effectively promotes CH4 desorption, with the JM sample having the highest displacement desorption efficiency.
Review
Chemistry, Multidisciplinary
Glaydson Simoes dos Reis, Helinando Pequeno de Oliveira, Sylvia H. Larsson, Mikael Thyrel, Eder Claudio Lima
Summary: This study focuses on natural carbon sources for preparing CEs towards high electrochemical performance in SCs. The influences of ACs' pore characteristics and nitrogen doping on the overall electrochemical performance are discussed.
Article
Chemistry, Multidisciplinary
Qiang Wei, Baolin Hu, Huihuang Fang, Chunshan Zheng, Xiaowei Hou, Deyi Gao, Hongjie Xu, Huihu Liu, Congqiu Shi, Jiaying Tong
Summary: In this study, two improved methods were proposed to estimate the gas content of deep-buried coal samples, and the Langmuir equation method was found to be relatively accurate.
Article
Engineering, Geological
Shirong Cao, Zhaolong Ge, Di Zhang, Zhe Zhou, Yiyu Lu, Hanyun Zhao
Summary: This study investigates the rock-breaking mechanism and pore structure evolution of typical reservoir rocks under ultra-high pressure water jet (UHP-WJ) impingement. The results show that different types of rocks exhibit different fracture mechanisms and pore structure evolutions under UHP-WJ impact. These findings provide important theoretical references for optimizing the development of unconventional natural gas reservoirs.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2022)
Article
Engineering, Chemical
Wendi Wang, Zhen Liu, Mingrui Zhang, He Yang
Summary: In this paper, nitrogen adsorption measurement and low-field nuclear magnetic resonance methods are used to test the structural parameters of adsorption pores of different coal samples. It is found that the complexity of the pore size distribution increases with the increase in metamorphic degree. There is a positive correlation between the fractal dimension and the maximum adsorption capacity of N-2.
Article
Chemistry, Multidisciplinary
Linjie Hu, Zengchao Feng, Dong Zhou
Summary: This study proposes the theory of heat injection-enhanced coalbed methane (CBM) extraction and performs on-site experiments to validate the method. The results show that two heat injections with specific water injection rate and temperature can achieve the best CBM extraction effect. The intermittent heat injection method significantly improves CBM concentration and daily gas production, and shortens the extraction time compared to traditional methods, indicating its technical advantages.
Article
Thermodynamics
Jie Zang, Jialong Liu, Jiabei He, Xiapeng Zhang
Summary: Coalbed methane (CBM) stored within the pores of coal has unique pore structures. This study used FIB-SEM tomography and deep learning-based segmentation to characterize the pore structures of a Chinese anthracite sample. The analysis showed that isolated pores were more numerous, but connected pores had larger surface area and pore volume. Mesopores played a significant role in pore number, surface area, and pore volume. The findings have implications for CBM recovery by emphasizing the importance of improving connectivity between pore components and fractures to enhance production rates and recoverability.
Article
Multidisciplinary Sciences
Yunhu Hu, Mu You, Guijian Liu, Zhongbing Dong
Summary: The study found that the average concentration of fluoride in centralized water sources is lower than that in decentralized sources, leading to corresponding lower health risk values. Infants and children were found to be more sensitive to the potential health risks of fluoride compared to adults.
SCIENTIFIC REPORTS
(2021)
Article
Geosciences, Multidisciplinary
Dameng Liu, Lijing Li, Zheng Zhao, Wei Chen, Yidong Cai, Yongkai Qiu, Yingfang Zhou
Summary: This study investigated the acoustic response of gas and/or water saturated coal rock and found that coal type and gas-water saturation affect the acoustic response of coalbed methane formations. The acoustic velocity, relative anisotropy, and their growth rates increase with increasing vitrinite reflectance, density, and water saturation.
FRONTIERS OF EARTH SCIENCE
(2023)
Article
Engineering, Environmental
Qifeng Jia, Dameng Liu, Yidong Cai, Yanbin Yao, Yuejian Lu, Yingfang Zhou
Summary: The swelling strain caused by methane adsorption in coal affects reservoir permeability, and the interaction between different scales of coal pores and adsorption behavior was investigated. Larger coal particle size leads to smaller temperature variation during adsorption and more capillary condensation of methane. Higher temperature results in more concentrated distribution of adhesion in coal.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Engineering, Environmental
Hao Wu, Yanbin Yao, Dameng Liu
Summary: This study investigated the water vapor sorption behavior in different maturity coal samples and identified two types of water adsorption mechanisms: attachment to oxygen functional groups and pore filling in hydrophilic and hydrophobic pores, respectively. The differences in water adsorption characteristics were found to be influenced by pore volume and the proportion of hydrophilic pores. The results also showed that water adsorption on methane adsorption in coal was attributed to the amount and proportion of hydrophilic pores.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Thermodynamics
Fengrui Sun, Dameng Liu, Yidong Cai, Yongkai Qiu
Summary: In this paper, the coupling control mechanism of coal rank-pressure on gas occurrence is studied, and a novel concept of surface control field is proposed. The influence mechanism of coal rank on methane adsorption capacity is revealed, and the difference of energy conversion mechanism between adsorption and desorption processes is clarified. A new concept of adsorption potential is also proposed based on the coal rank-pressure linkage model of energy conversion.
Article
Engineering, Environmental
Sijian Zheng, Yanbin Yao, Dameng Liu, Shuxun Sang, Shiqi Liu, Meng Wang, Xiaozhi Zhou, Ran Wang, Sijie Han, Tong Liu
Summary: This article proposed an innovative methodology to quantitatively characterize the multiphase water in coals, applicable to both water-saturated and sub-saturated coals, by combining theory and experiment.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Energy & Fuels
Yong Liu, Yanbin Yao, Dameng Liu, Chi Zhang
Summary: Forced imbibition in shale reservoirs is crucial for efficient recovery of shale gas, but it can also lead to low flowback efficiency and reservoir damages. This study investigated imbibition behaviors in Longmaxi shales under four different boundary conditions using nuclear magnetic resonance technology. The results showed that the shale bedding structure is the key factor determining the imbibition dynamics and patterns under different boundary conditions.
Article
Energy & Fuels
Zihao Wang, Yidong Cai, Dameng Liu, Feng Qiu, Fengrui Sun, Yingfang Zhou
Summary: The structure of coal plays a crucial role in the exploration and development of coalbed methane. Traditional coal core observations are not applicable in unexplored coal seams without CBM wells and are time-consuming. Geophysical-logging interpretation of the coal structure is more efficient and economical, but improvement is needed in qualitative methods. Machine learning methods, including MLR, RF, and DNN, proved to be effective in identifying the coal structure accurately and efficiently.
INTERNATIONAL JOURNAL OF COAL GEOLOGY
(2023)
Article
Geosciences, Multidisciplinary
Hao Wu, Yanbin Yao, Xuejia Du
Summary: There is water in coal pores in the form of adsorption, which can negatively affect coalbed methane production and carbon dioxide storage in coal. Particle size influences water adsorption in coal, with smaller particles having higher rates and amounts of water adsorption. However, the impact of particle size on water adsorption is weaker for high-rank coal compared to low-rank coal. The measurement of water adsorption properties by particles may not be applicable to real coal blocks. Nonetheless, the change in particle size does affect the flow rate of different samples. This study deepens the understanding of water adsorption mechanism in coal with typical particle sizes.
NATURAL RESOURCES RESEARCH
(2023)
Article
Thermodynamics
Changjing Gao, Dameng Liu, Veerle Vandeginste, Yidong Cai, Fengrui Sun
Summary: This study investigates the occurrence mechanism of multiple fluids in coal reservoirs through experimental data and innovative methods. The results show that coal rank, gas composition, and adsorption heat all affect the adsorption capacity and performance.
Article
Energy & Fuels
Hao Wu, Yanbin Yao, Simon Emmanuel
Summary: A novel workflow utilizing interactive machine learning software to improve pore segmentation accuracy in coal samples is presented. By manually labeling a portion of the images and training a classifier using features like intensity, edge, and texture, the machine learning method outperforms grayscale threshold segmentation in accurately segmenting the images and estimating porosity. This study highlights the potential of machine learning techniques in reliably characterizing the pore structure of coal and other geological materials.
Article
Geosciences, Multidisciplinary
Xiaona Zhang, Yanbin Yao, Guibin Zhang, Ruying Ma, Zefan Wang
Summary: This study used cores, thin sections, imaging logs, and laboratory measurements to investigate the factors influencing the formation and development of natural fractures in the Bozhong 19-6 gas field. Both tectonic fractures and dissolution fractures are well developed and interconnected. Lithology, stress, and weathering were found to affect fracture formation and development. A reservoir evolution pattern was proposed to target favorable reservoirs in the study area.
MARINE AND PETROLEUM GEOLOGY
(2023)