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.
Review
Energy & Fuels
He Li, Jiawei He, Jiexin Lu, Baiquan Lin, Yi Lu, Shiliang Shi, Qing Ye
Summary: Chemical stimulation is a potential technology for enhancing coal permeability. Current research focuses on developing efficient chemical stimulation techniques and understanding the mechanisms of permeability enhancement. Laboratory studies have shown that acidising, oxidizing, organic solvent extraction, and electrochemistry stimulation techniques can improve coal permeability. Factors such as coal composition, pore-fracture structure, chemical reagent type, precipitation formation, in-situ stress, and water blocking influence the efficiency of permeability enhancement. The field application of chemical stimulation techniques is still limited, and future research should investigate their feasibility and consider the synergistic effects of chemical and physical stimulation techniques.
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
Energy & Fuels
Mohammadreza Zare Reisabadi, Mohammad Sayyafzadeh, Manouchehr Haghighi
Summary: This study investigates the effects of matrix swelling and well trajectory on permeability in coal seam gas reservoirs during CO2 injection. The results show that vertical injection wells experience a significant decline in permeability due to swelling, while horizontal wells do not.
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
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
Geosciences, Multidisciplinary
Yina Yu, Zhaoping Meng, Caixia Gao, Yixin Lu, Jiangjiang Li
Summary: The permeability of deep coal reservoirs in coalbed methane extraction is affected by temperature and pore pressure. This study explores the permeability evolution during CBM production under different temperatures and establishes a coupling coal permeability function. The results show the sensitivity of coal reservoir permeability to stress and temperature, and provide guidance for reasonable drainage of CBM wells in different geothermal fields.
NATURAL RESOURCES RESEARCH
(2022)
Article
Engineering, Chemical
Vanessa Santiago, Francy Guerrero Zabala, Angel J. Sanchez-Barra, Nathan Deisman, Richard J. Chalaturnyk, Ruizhi Zhong, Suzanne Hurter
Summary: This study investigates the impact of fracture networks and interburden rock on the dynamics of permeability by analyzing a series of 3D printed coal seam gas samples under various flow conditions. The results show that the 3D printed rock samples treated with sodium silicate exhibit similar pore compressibility to coal, and specimens with multi-directional fractures have lower fracture compressibility compared to those with unidirectional fractures.
CHEMICAL ENGINEERING RESEARCH & DESIGN
(2022)
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
Junqiang Kang, Derek Elsworth, Xuehai Fu, Shun Liang, Hao Chen
Summary: This study analyzed the impact of water saturation on the permeability of coal reservoirs through experiments and finite element methods, finding that changes in E and v can lead to a faster or slower decrease in permeability, with E having a more significant effect on permeability.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Environmental Sciences
Xiaoming Ni, Xuebin Tan, Sen Yang, Bin Xu, Xiaokang Fu
Summary: The evaluation of CBM production potential considering different coal structures can better reflect the objective facts, especially in areas with strong heterogeneity in coal structure. The proposed method provides a novel approach to accurately evaluate CBM production potential in regions with highly heterogeneous coal structures.
ENVIRONMENTAL EARTH SCIENCES
(2021)
Article
Energy & Fuels
He Li, Chaoping Xu, Guanhua Ni, Jiexin Lu, Yi Lu, Shiliang Shi, Min Li, Qing Ye
Summary: This paper introduces the concept of using microwave-assisted oxidation to enhance the permeability of coalbed methane (CBM) reservoirs. The study shows that microwave-assisted oxidation can change the physicochemical structure of coal and improve its permeability.
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
Geosciences, Multidisciplinary
Di Gao, Huiling Guo, Bianqing Guo, Kaili Tan, Hengxing Ren
Summary: In this study, the pore structure characteristics of No. 3 coal seams in Qinshui Basin after microbial treatment were analyzed. It was found that microorganisms participated in the degradation of coal reservoirs and promoted the production of methane gas. The modification of meso-macropores was more significant, resulting in stabilized pore diameter, smoother pores, decreased specific surface area, and increased pore volume, which are beneficial for the adsorption and production of coalbed methane (CBM) after microbial treatment.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Energy & Fuels
Shaojie Chen, Jicheng Zhang, Dawei Yin, Xianzhen Cheng, Ning Jiang
Summary: The gas-water flow in coal cleats is crucial for coalbed methane production. This study uses advanced microchip technology to predict the optimal coal cleat and conducts gas and liquid injection experiments on microchannels to understand the flow behavior. The research reveals that gas is more sensitive to microchannel size than liquid and a hydrophilic environment and suitable flow rate can increase two-phase relative permeability. The steady-state method may misrepresent the physics of fluid flows in microchannels.