Article
Engineering, Environmental
Jia Lin, Ting Ren, Yuanping Cheng, Jan Nemcik
Summary: CO2 geo-sequestration in unminable coal seams shows promise in reducing greenhouse gas emissions and enhancing coal bed methane recovery, but faces challenges in permeability reduction effects post-injection.
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
(2021)
Article
Geosciences, Multidisciplinary
Zhaolong Ge, Yudong Hou, Zhe Zhou, Zepeng Wang, Maolin Ye, Shan Huang, Hui Zhang
Summary: A method of reconstructing 3D pore-fracture networks using nuclear magnetic resonance and CT was proposed, and the relationship between the structural characteristics of the networks and permeability was studied. The permeability evolution under high-pressure CO2 was investigated using COMSOL software, and a reliable model was established for predicting permeability.
NATURAL RESOURCES RESEARCH
(2023)
Article
Energy & Fuels
Min Chen, Shakil A. Masum, Hywel R. Thomas
Summary: This work presents the development of a 3D hybrid coupled dual continuum and discrete fracture model for simulating coupled flow, reaction and deformation processes relevant to fractured reservoirs with multiscale fracture system, e.g., coal and shale, efficiently and accurately. The hybrid model combines the dual continuum approach and the discrete fracture approach, and a combination of different types of elements is used for spatial discretization. The coupling between the two models is achieved via the principle of su-perposition. A hybrid MPI/ OpenMP parallel scheme is implemented to reduce computational time. The results demonstrate the capabilities of the model in capturing the effects of multiscale fracture system and their coupled behaviour during CO2 injection and methane recovery from coal reservoirs.
INTERNATIONAL JOURNAL OF COAL GEOLOGY
(2022)
Article
Energy & Fuels
Wei He, Yuedu Chen, Haojie Lian, Weiguo Liang, Jiwei Yan, Xiaoxia Song
Summary: This study investigates the influence of supercritical carbon dioxide (ScCO2) on the pore structure of coal at different temperatures. The results show that as the temperature increases, the porosity of anthracite increases, while the proportion of micropores and mesopores decreases and the proportion of macropores increases. CT scanning reveals that the temperature and ScCO2 coupling effect accelerates the growth of anthracite porosity. The study provides significant insights into the temperature effect on coal reservoir porosity evolution during CO2 storage.
Article
Energy & Fuels
Ming-Yao Wei, Jishan Liu, Ying-Ke Liu, Zhang-Hao Liu, Derek Elsworth
Summary: Gas transport in coal leads to stress variation, affecting porosity and permeability evolution. Neglecting the heterogeneity and anisotropy of coal in dual porosity models can deviate from real physical mechanisms. Advanced virtual simulation incorporating real fracture geometry reveals non-uniform distribution of fracture geometry as a key factor impacting permeability change.
Article
Energy & Fuels
Min Hao, Chengwu Li, Yilin Wang, Heng Zhang
Summary: This study explores the fundamental understanding of the coal-gas interaction and reveals the three-stage evolution behavior of sorption and strain kinetics. Various factors have significant effects on the kinetic behavior. The findings have implications for improving CBM extraction efficiency.
Article
Chemistry, Multidisciplinary
Hu Wen, Jianchi Hao, Li Ma, Xuezhao Zheng
Summary: The study revealed that the process of CO2 replacing CH4 can be divided into different stages, with desorption amount varying with time and temperature, and replacement ratio showing a positive correlation with replacement time. Overall, an increase in CO2 injection pressure would result in higher cumulative displacement ratio.
Article
Energy & Fuels
Hongbo Yao, Yuedu Chen, Weiguo Liang, Xiaoxia Song
Summary: The thermal effect of coal induced by supercritical CO2 adsorption and desorption was studied experimentally. It was found that CO2 adsorption and desorption increased and decreased the coal's temperature, respectively. The induced temperature variation depended on coal rank, CO2 pressure, and equilibrium temperature. The desorption hysteresis phenomenon was correlated with changes in the coal's functional groups, and the effect was weakened by increasing the equilibrium temperature.
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
Energy & Fuels
Guanglei Zhang, P. G. Ranjith, Zhongsheng Li, Mingzhong Gao, Zhaoyang Ma
Summary: In this study, the long-term effects of CO2 injection on the structural and mechanical properties of water-saturated coal were investigated. It was found that the presence of water during CO2 injection resulted in significant changes in the mechanical properties of coal, primarily due to sorption-induced cracking causing structural damage. The extent of reduction in mechanical properties was less compared to pure CO2 injection, potentially due to the hindrance of CO2 sorption by water.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2021)
Article
Engineering, Environmental
Junqiang Kang, Derek Elsworth, Xuehai Fu, Shun Liang, Hao Chen
Summary: The adsorption of methane in coal releases heat and causes thermal expansion, which is related to adsorption swelling and adsorption capacity. The study finds that thermal expansion due to adsorption heat may contribute to 35% of the total adsorption strain under ideal isentropic conditions. Laboratory experiments cannot accurately measure the thermal expansion during adsorption, but reduced heat dissipation in coalbed reservoirs may retain thermal deformation and affect short-term permeability evolution.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Geochemistry & Geophysics
Jia Kong, Baiquan Lin, Chuanjie Zhu, Ting Liu, Xiangguo Kong
Summary: In this study, a dynamic elastic modulus model was established to analyze the effect of gas pressure on the elastic modulus of coal. A permeability model considering internal swelling deformation was also constructed. The rationality of the models was validated through laboratory experiments.
Article
Chemistry, Physical
I. E. Men'shchikov, A. Shkolin, A. A. Fomkin, E. Khozina
Summary: The study investigated methane adsorption on recuperated activated carbon AR-V, showing significant changes in adsorption amount with temperature and pressure variations. It was found that the thermodynamic state functions of the adsorption system changed drastically after methane molecules occupied high-energy adsorption sites. Additionally, the isosteric heat capacity of the methane/AR-V system displayed temperature dependence during adsorption.
ADSORPTION-JOURNAL OF THE INTERNATIONAL ADSORPTION SOCIETY
(2021)
Article
Energy & Fuels
Jiawei Li, Chenhao Sun
Summary: This study investigates the dynamic deformation of kerogen upon CH4/CO2 competitive adsorption in unconventional shale and coal seams, showing that the flexible nature of kerogen leads to increased capacity for CH4 adsorption and CO2 storage, as well as enhanced selectivity in competitive adsorption.
INTERNATIONAL JOURNAL OF COAL GEOLOGY
(2022)
Article
Environmental Sciences
Behshid Khodaei, Hossein Hashemi, Shokoufeh Salimi, Ronny Berndtsson
Summary: This research uses InSAR technique to measure the deformation of the peatland's surface in south Sweden in response to recent seasonal and extreme weather conditions. The results show significant uplift in most of the investigated peat areas, indicating large carbon uptake by the underground peat. This emphasizes the importance of InSAR as an efficient and accurate technique to monitor the deformation rate of peatlands, which have a vital role in the global carbon cycle.
ENVIRONMENTAL RESEARCH LETTERS
(2023)
Article
Thermodynamics
HamidReza Tamaddon Jahromi, Samuel Rolland, Jason Jones, Alberto Coccarelli, Igor Sazonov, Chris Kershaw, Chedly Tizaoui, Peter Holliman, David Worsley, Hywel Thomas, Perumal Nithiarasu
Summary: A novel modelling approach is proposed to study ozone distribution and destruction in indoor spaces. The methodology was validated against experimental measurements and showed good agreement in predicting the time evolution of ozone concentration at different locations within the enclosed space. The study introduces a computational methodology for predicting ozone concentration levels during a disinfection process, with a parametric study evaluating the impact of system settings on ozone concentration variation over time.
INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW
(2022)
Article
Environmental Sciences
Sivachidambaram Sadasivam, Renato Zagorscak, Hywel Rhys Thomas, Krzysztof Kapusta, Krzysztof Stanczyk
Summary: This paper investigates the inorganic constituents generated during underground coal gasification (UCG) under different operating conditions. It was found that increasing the water content in the oxidants decreased cationic elements but increased anionic species concentrations. Temperature had a minor impact on the experiments, while high-pressure experiments at the optimal temperature showed significant reduction in cationic element generation. Both coal specimens produced high amounts of anionic species, with the hard bituminous coal from Poland showing higher reactivity. The inorganic composition in the solid residue was used to predict dissolved product concentrations when interacting with deep coal seam water during UCG cavity flooding. Additionally, changes in groundwater geochemistry were observed, indicating the need for further study on their transportation in the subsurface.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2022)
Review
Computer Science, Interdisciplinary Applications
Bin Chen, Beatriz Ramos Barboza, Yanan Sun, Jie Bai, Hywel R. Thomas, Martin Dutko, Mark Cottrell, Chenfeng Li
Summary: This paper discusses the physical processes, numerical models, and commercial software related to hydraulic fracturing, analyzing their effects and highlighting pros and cons. Based on these discussions, recommendations for further research are provided.
ARCHIVES OF COMPUTATIONAL METHODS IN ENGINEERING
(2022)
Article
Thermodynamics
Wu Gao, Renato Zagorscak, Hywel Rhys Thomas, Ni An
Summary: This paper introduces a coupled thermal-hydraulic-chemical numerical model to study temperature development and solid-gas conversion in underground coal gasification. The model considers various factors such as gas flow, solid mass loss, and chemical reactions, accurately predicting the gasification process.
COMBUSTION THEORY AND MODELLING
(2022)
Article
Engineering, Multidisciplinary
Jinlong Fu, Dunhui Xiao, Dongfeng Li, Hywel R. Thomas, Chenfeng Li
Summary: This paper presents an efficient method that combines machine learning-based characterization of 2D images with statistical reconstruction of 3D microstructures. By fitting supervised machine learning models, the latent stochasticity of 2D images is mastered, and a morphology integration scheme is developed to project the 2D morphological statistics into the 3D space. Experimental results confirm that the proposed method can economically and accurately reproduce 3D microstructures that preserve the statistical characteristics, geometrical irregularities, long-distance connectivity, and anisotropy present in 2D cross-sectional images.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2022)
Article
Engineering, Geological
Wu Gao, Renato Zagorscak, Hywel Rhys Thomas
Summary: This paper presents a coupled thermo-mechanical model for investigating the ground response during underground coal gasification (UCG). The simulation results show that the thermal expansion coefficient can influence the thermo-mechanical response of geologic materials to a certain extent.
INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS
(2022)
Article
Energy & Fuels
Ni An, Renato Zagorscak, Hywel Rhys Thomas
Summary: Numerical simulations show that when reactor behavior and surrounding strata changes are as expected, CBM-UCG activities are unlikely to have negative environmental impacts during the UCG process. This research can provide insights for environmental decision making, regulation, and management to prevent reduction in gasification efficiency, conduct post-UCG (E)CBM processes, and mitigate UCG gas leakage and contamination of surrounding aquifers, highlighting the need for additional information in CBM-UCG activities.
INTERNATIONAL JOURNAL OF COAL GEOLOGY
(2022)
Article
Engineering, Multidisciplinary
Yue Ma, Xiaohui Chen, Lee J. Hosking, Hai-Sui Yu, Hywel R. Thomas
Summary: This paper presents a coupled THMC model that incorporates the interactions between chemical and thermal osmosis. By extending the Mixture Coupling Theory and using a non-equilibrium thermodynamics framework, the study investigates the effects of chemical and thermal osmosis on water flow and mechanical deformation.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2022)
Article
Engineering, Geological
Min Chen, Shakil Masum, Sivachidambaram Sadasivam, Hywel Thomas
Summary: This study proposes an effective stress model for investigating the anisotropy of coal swelling in fractured porous media. The model considers the change in stress on the solid-fluid interface induced by gas adsorption. Experimental results show that coal swelling is greater in the direction perpendicular to the bedding plane than in the parallel plane. The evolution of anisotropic stress-dependent permeability behavior is described by direction dependent fracture compressibility. The presented model provides a tool for quantifying gas adsorption-induced anisotropic coal swelling and permeability behaviors.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2022)
Article
Energy & Fuels
Sivachidambaram Sadasivam, Shakil Masum, Min Chen, Kamil Stanczyk, Hywel Thomas
Summary: This study explores the CO2 adsorption-desorption kinetics of bituminous coal under low pressure injection and compares different models to fit the data. The results suggest that bulk pore diffusion, surface interaction, and multilayer adsorption are the rate-determining steps.
Article
Energy & Fuels
Min Chen, Shakil A. Masum, Hywel R. Thomas
Summary: This work presents the development of a 3D hybrid coupled dual continuum and discrete fracture model for simulating coupled flow, reaction and deformation processes relevant to fractured reservoirs with multiscale fracture system, e.g., coal and shale, efficiently and accurately. The hybrid model combines the dual continuum approach and the discrete fracture approach, and a combination of different types of elements is used for spatial discretization. The coupling between the two models is achieved via the principle of su-perposition. A hybrid MPI/ OpenMP parallel scheme is implemented to reduce computational time. The results demonstrate the capabilities of the model in capturing the effects of multiscale fracture system and their coupled behaviour during CO2 injection and methane recovery from coal reservoirs.
INTERNATIONAL JOURNAL OF COAL GEOLOGY
(2022)
Article
Green & Sustainable Science & Technology
Shakil A. Masum, Min Chen, Lee J. Hosking, Kamil Stanczyk, Krzysztof Kapusta, Hywel R. Thomas
Summary: This article investigates the challenges of CO2 storage in coal and proposes a novel solution. Through pre-operational simulation studies, it is found that the targeted amount of CO2 can be injected into the coal seams without significant loss of permeability or injectivity by varying the length of horizontal wells and injection conditions. Furthermore, the spread of CO2 is predicted to be contained within the model domain.
INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL
(2022)
Article
Chemistry, Multidisciplinary
Shakil A. Masum, Sivachidambaram Sadasivam, Min Chen, Hywel R. Thomas
Summary: This study aims to improve the understanding of low and subcritical CO2 adsorption-desorption behavior of bituminous coals and evaluate the potential for CO2 storage in shallow-depth coal seams. The research conducted manometric sorption experiments on coal cores obtained from a 30 m deep coal seam in Poland and found that adsorption capacities correlated with void volume and equilibrium time. Hysteresis behavior indicated CO2 pore diffusion and condensation, which is vital for assessing low-pressure CO2 injection and storage capabilities of shallow coal seams.
Article
Energy & Fuels
Maria Wetzel, Christopher Otto, Min Chen, Shakil Masum, Hywel Thomas, Tomasz Urych, Bartlomiej Bezak, Thomas Kempka
Summary: Deep un-mineable coal deposits have a high potential for storing carbon dioxide (CO2) due to their ability to adsorb large amounts of CO2. However, there are geomechanical risks associated with CO2 storage, such as fault reactivation and ground surface uplift. This study assessed the hydromechanical impacts of CO2 storage in a coal deposit by using numerical simulations. The results showed minimal vertical displacements and no fault slip or dilation, but it is important to accurately determine the stress regime and fault properties for a comprehensive risk assessment.
Article
Energy & Fuels
Min Chen, Shakil A. Masum, Hywel R. Thomas
Summary: This study presents a 3D numerical model for understanding the flow processes in naturally fractured coal reservoirs. The model considers gas flow, adsorption, and deformation at the scale of coal cleat and matrix blocks. Different gas transport mechanisms and the Langmuir kinetic model are applied to describe the mass exchange process between free and adsorbed phases. The accuracy of the model is validated against experimental results.
GAS SCIENCE AND ENGINEERING
(2023)
