Article
Chemistry, Multidisciplinary
Keming Sun, Peng Chen, Shucui Zhang, Kai Li, Xingang Zhang
Summary: This study investigates the experimental and numerical responses of coal specimens, focusing on the fracturing induced by a supercritical CO2 explosion. Cleats in the coal seam are found to absorb and reflect stress waves, hindering crack propagation. Factors such as the dip angle and aperture of the cleat, as well as the distance from the blast hole, are discussed in relation to their influence on crack propagation.
Article
Engineering, Geological
Wenzhuo Cao, Qinghua Lei, Wu Cai
Summary: The presence and distribution of natural fractures in coal significantly influence its deformation and permeability. This research utilized a finite element model to simulate the behavior of fractured coal under various stress loading conditions, revealing correlated variations among shear-induced cleat dilation, damage in coal matrix, and equivalent permeability. Findings suggest that coal mining at low stress rates promotes stability of surrounding coal seams, and mining in parallel to cleat directions is preferable.
ROCK MECHANICS AND ROCK ENGINEERING
(2021)
Article
Energy & Fuels
Haijun Guo, Hanlu Tang, Yuchen Wu, Kai Wang, Chao Xu
Summary: Coal is a complex dual-porosity porous medium composed of fractures and coal matrices. The gas seepage characteristics in coals are closely related to the coal matrix-fracture structures and can be simplified to equivalent scale characteristics. A simplified permeability evolution model and a method for measuring permeability in coal seams were proposed, enriching the theory of gas seepage and laying a foundation for studying the evolution mechanism of coal permeability during plastic deformation.
Article
Energy & Fuels
Mingyao Wei, Jishan Liu, Derek Elsworth, Yingke Liu, Jie Zeng, Zhihong He
Summary: The study extends the conventional dual porosity model to account for equilibration time lag between matrix and fractures, dividing the matrix REV into two sub-REVs using the MINC concept. The model is verified against experimental observations of coal permeability evolution under constant effective stress for over 80 days, showing significant impact of matrix strain variations on coal permeability evolution.
Article
Water Resources
Luyu Wang, Fabrice Golfier, Anne-Julie Tinet, Weizhong Chen, Cornelis Vuik
Summary: This study investigates the numerical method and equivalent continuum approach for fluid flow in fractured porous media. By developing an efficient implicit scheme and utilizing an improved equivalent continuum approach, the proposed numerical scheme improves convergence condition and computational efficiency, and successfully simulates fluid flow in fracture networks with complex geometry.
ADVANCES IN WATER RESOURCES
(2022)
Article
Computer Science, Information Systems
Mohamed Soufiane Jouini, Jorge Salgado Gomes, Moussa Tembely, Ezdeen Raed Ibrahim
Summary: The paper introduces a multiscale approach to simulate permeability and porosity in heterogeneous carbonate samples using machine learning for texture classification. The study investigates fine and coarse scale properties, with experimental validation at the fine scale using 3D printing technology.
Article
Mechanics
Ya Meng, Zhiping Li
Summary: This study investigates the gas slippage effect in coal samples with different coalification degrees through helium permeability experiments. The research reveals the characteristics of gas permeability variations in coal samples and the influence of coalification degrees, coal pore structures, and different gases on the gas slippage effect. The study establishes a prediction model for coalbed methane (CBM) well production considering the gas slippage effect and reveals the degree of impact on CBM well productivity.
Article
Engineering, Chemical
Qingquan Liu, Peng Chu, Yuanyuan Liu, Lei Xia, Liang Wang
Summary: Understanding the permeability distribution is crucial for the design of hydraulic strengthened gas extraction. The existing methods are not able to directly determine the nonuniform coal seam permeability after hydraulic flushing. To address this issue, a new method called equivalent permeability and radius (EPR) method is proposed. The EPR method simplifies and expresses the coal seam permeability distribution after hydraulic flushing using equivalent permeability and equivalent permeability-enhancement radius determined by field measurement and gas migration models simulation. The EPR method does not rely on coal stress and mechanical parameters, and it accurately evaluates the permeability improvement effect.
TRANSPORT IN POROUS MEDIA
(2022)
Article
Geosciences, Multidisciplinary
Jianhua Li, Bobo Li, Qiaoyun Cheng, Zheng Gao
Summary: Permeability is a key parameter for understanding coalbed methane mining and carbon dioxide geological storage. Coal exhibits distinct deformation characteristics due to the presence of soft and hard parts in fractures, which affect permeability. The study also found that coal shows strong anisotropy under reservoir conditions, with varying permeability in different directions.
NATURAL RESOURCES RESEARCH
(2021)
Article
Energy & Fuels
Jie Zhu, Jun Tang, Chenyu Hou, Tangsha Shao, Yuhan Zhao, Jinge Wang, Li Lin, Jinjia Liu, Yaodong Jiang
Summary: Fluid flow modeling of coalbed methane wells is crucial for predicting gas production and designing effective depressurization schemes. Hydraulic fracturing plays a significant role in improving reservoir permeability. The numerical simulation results in this study show that considering the permeability evolution between different areas is essential for accurately estimating CBM well production.
Article
Energy & Fuels
Jiangfeng Cui, Guangyao Si
Summary: The study utilizes the finite difference method to conduct numerical simulation of micro-fractures in shale rocks, characterizing their impact through the concept of normalized equivalent permeability. It comprehensively investigates the effects of horizontal bedding fractures and vertical structural fractures on the anisotropic permeability of shale, providing valuable insights for enhancing oil/gas recovery in shale reservoirs.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2021)
Article
Energy & Fuels
Chenhong Zhu, Jianguo Wang, Shuxun Sang, Wei Liang
Summary: This study proposes a multiscale convolutional neural network model (MsNet) to efficiently predict the equivalent permeability of a complex multiscale fracture network. The MsNet model performs better than other models on datasets with higher fracture density.
GEOENERGY SCIENCE AND ENGINEERING
(2023)
Article
Geochemistry & Geophysics
Shuiqing Hu, Daobing Wang, Yipeng Li, Xiongfei Liu, Fujian Zhou, Meng Wang, Chunming He, Bo Yu
Summary: This study establishes a 3D finite element model of coal rock considering the variation in pore pressure caused by methane desorption, the linear thermal expansion effect, and coal rock skeleton shrinkage and deformation. It analyzes the variation in permeability, porosity, stress, temperature, and pore pressure within the coal rock and reveals that the evolution of porosity and permeability is a thermo-hydro-mechanical coupling process related to mechanical heterogeneity, thermal expansion effect, pore pressure change, and stressed deformation in the coal rock skeleton.
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
Thermodynamics
Lulu Sun, Chen Zhang, Gang Wang, Qiming Huang, Quanlin Shi
Summary: In this study, a self-built high-temperature tube furnace was used to heat coal samples at different temperatures and gas atmospheres in order to investigate the evolution of pore and fracture structures during spontaneous combustion of coal. X-ray CT technology was utilized to scan the coal samples and extract the three-dimensional pore structure and equivalent pore network model. The results showed that the porosity and fractal dimension of coal samples heat-treated in an air atmosphere were significantly higher than those heat-treated in a nitrogen atmosphere. The connectivity and permeability of the coal samples were also affected, with better connectivity observed in the air atmosphere. Nitrogen injection during heating had a stronger inhibitory effect on the development of pore and fracture structures, leading to decreased permeability. This research suggests that nitrogen injection can be an effective strategy to prevent and control coal spontaneous combustion.
Article
Engineering, Civil
T. X. Wu, H. L. Xing
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART F-JOURNAL OF RAIL AND RAPID TRANSIT
(2018)
Article
Geosciences, Multidisciplinary
Liu Xiangchong, Xing Huilin, Zhang Dehui
ACTA GEOLOGICA SINICA-ENGLISH EDITION
(2018)
Article
Water Resources
Jie Yi, Huilin Xing
ADVANCES IN WATER RESOURCES
(2018)
Article
Environmental Sciences
Mei-ben Gao, Tian-bin Li, Lu-bo Meng, Chun-chi Ma, Hui-lin Xing
JOURNAL OF MOUNTAIN SCIENCE
(2018)
Article
Energy & Fuels
Fangwen Chen, Shuangfang Lu, Xue Ding, Xipeng He, Huilin Xing
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2018)
Article
Energy & Fuels
Yupeng Jiang, Huilin Xing
INTERNATIONAL JOURNAL OF OIL GAS AND COAL TECHNOLOGY
(2018)
Article
Energy & Fuels
Fei Ren, Lei Ge, Thomas E. Rufford, Huilin Xing, Victor Rudolph
JOURNAL OF NATURAL GAS SCIENCE AND ENGINEERING
(2018)
Article
Geology
Xiangchong Liu, Yue Ma, Huilin Xing, Dehui Zhang
ORE GEOLOGY REVIEWS
(2018)
Article
Geosciences, Multidisciplinary
Dalei Peng, Qiang Xu, Xianlin Zhang, Huilin Xing, Shuai Zhang, Kai Kang, Xing Qi, Yuanzhen Ju, Kuanyao Zhao
JOURNAL OF ASIAN EARTH SCIENCES
(2019)
Article
Energy & Fuels
Fei Ren, Lei Ge, Arash Arami-Niya, Thomas E. Rufford, Huilin Xing, Victor Rudolph
INTERNATIONAL JOURNAL OF COAL GEOLOGY
(2019)
Article
Energy & Fuels
Fei Ren, Lei Ge, Vitaliy Stelmashuk, Thomas E. Rufford, Huilin Xing, Victor Rudolph
JOURNAL OF NATURAL GAS SCIENCE AND ENGINEERING
(2019)
Article
Engineering, Geological
Huilin Xing, Zhiting Han
Article
Geochemistry & Geophysics
Guodong Jin, Huilin Xing, Tianbin Li, Rongxin Zhang, Junbiao Liu, Zhiwei Guo, Zihan Ma
Summary: This study focuses on the numerical simulation of fluid flow in unconventional reservoirs with fractures, demonstrating the dominance of fractures near the wellbore and the presence of three distinct flow regimes in the reservoir with fractures intersecting the well. The validation and application of the model show the feasibility and practicality of the integrated approach for investigating transient-pressure behaviors in unconventional reservoirs.
Article
Energy & Fuels
Yiran Zhu, Zhang Shi, Huilin Xing, Zhongwei Chen
Summary: Coal cleats are the main flow path for gas and water during coal seam gas (CSG) production and their aperture plays a crucial role in capillary pressure and gas production rate. This study develops an improved capillary pressure model that considers the impact of cleat aperture change on capillary pressure value and residual saturation. The model is extended to a reservoir scale, revealing that changes in cleat aperture can significantly alter capillary pressure and gas production rate. The findings provide valuable insights into understanding the influence of cleat aperture change on capillary pressure during CSG production.
JOURNAL OF NATURAL GAS SCIENCE AND ENGINEERING
(2022)
Article
Geochemistry & Geophysics
Yao Qi, Xu XiWei, Xing HuiLin, Cheng Jia, Jiang GuoYan, Ma WeiYu, Liu Jie, Yang Wen
CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION
(2018)