Coal-bed methane geology of the No. 2 coal seam in Fengfeng Coalfield, North China

Lv, Dawei; Lu, Changyong; Wen, Zhen; Song, Hongzhu; Yin, Shuai

doi:10.1007/s12517-019-4703-7

Cited by 7 publications

(2 citation statements)

References 49 publications

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“…The Fengfeng mining area has undergone strong deformation since the Neogene and mainly developed NE-SW structural lines [27], including folds and faults, which also made the coal seam more severely deformed. These strongly deformed structures have seriously affected the exploration and development of coalbed methane in the Fengfeng mining area [28], as well as the safety production of coal mines.…”

Section: Geological Backgroundmentioning

confidence: 99%

Macromolecular Structure Controlling Micro Mechanical Properties of Vitrinite and Inertinite in Tectonically Deformed Coals—A Case Study in Fengfeng Coal Mine of Taihangshan Fault Zone (North China)

et al. 2020

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In order to study the evolution of the mechanical properties and macromolecular structures in different macerals of tectonically deformed coal (TDC), vitrinite and inertinite samples were handpicked from six block TDCs in the same coal seam with an increasing deformation degree (unaltered, cataclastic, porphyroclast, scaly and powdery coal). The micro mechanical properties were tested by the nanoindentation experiment and the macromolecular structures were measured using 13C nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). The results show that the range of hardness and elastic modulus of inertinite is 0.373–1.517 GPa and 4.339–12.158 GPa, respectively, which is significantly higher than that of vitrinite with values of 0.278–0.456 GPa and 4.857–7.810 GPa, respectively. From unaltered coal to powdery coal, the hardness of vitrinite and inertinite gradually decreases, with the difference between these macerals becomes smaller and the elastic modulus of vitrinite shows an increasing trend, while that of inertinite was more variable. Both the NMR and FITR results reveal that the macromolecular structure of inertinite has similar structural transitions as vitrinite. As the degree of deformation increases, the aliphatic side chains become shorter and the aromaticity is increasing. Macromolecular alterations caused by tectonic stress is expected to produce defects in the TDCs, therefore there should be more interspacing among the macromolecular groups for the extrusion of macromolecules caused by the indenter of the nanoindentation experiment, thereby reducing the hardness. The elastic modulus of coal is believed to be related to intermolecular forces, which are positively correlated to the dipole moment. By calculating the dipole moments of the typical aromatic molecular structures with aliphatic side chains, the detachment of the aliphatic side chains and the growth of benzene rings can both increase the dipole moment, which can promote elastic modulus. In addition, the increasing number of benzene rings can create more π-π bonds between the molecules, which can lead to an increase in the intermolecular forces, further increasing the elastic modulus.

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Section: Geological Backgroundmentioning

confidence: 99%

Macromolecular Structure Controlling Micro Mechanical Properties of Vitrinite and Inertinite in Tectonically Deformed Coals—A Case Study in Fengfeng Coal Mine of Taihangshan Fault Zone (North China)

et al. 2020

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“…As an important unconventional clean energy, the development of coalbed methane (CBM) reservoirs has gradually replaced the exploitation of conventional natural gas (Clarkson et al 2005;Zhao et al 2018;Lv et al 2019). Since most of the CBM in the reservoir is adsorbed on the surface of coal particles or framework, CBM needs to be produced by drainage and depressurization (McKee and Bumb 1987).…”

Section: Introductionmentioning

confidence: 99%

Experimental study on water saturation effect on coal sample permeability under different effective stresses

et al. 2023

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During the drainage and production of coalbed methane (CBM) wells, the Constant changes in stress and water saturation of reservoir restricts the dynamic change of the reservoir permeability. By carrying out stress sensitivity experiments with different water saturations in coal, the correlation between permeability and the coupling of effective stress and water saturation was analyzed. The water saturation sensitivity and stress sensitivity of reservoir were evaluated by the stress sensitivity index (S), permeability damage rate (PDR), and stress sensitivity coefficient (αk), and the change law of coal permeability under different stresses with different water saturations was revealed. The results showed that the coal reservoir permeability decreased with increasing stress following a negative exponential function and decreased nearly linearly with increasing water saturation. In addition, the coal water saturation sensitivity was positively correlated with effective stress, and the coal stress sensitivity was positively correlated with water saturation. Finally, a mathematical model for predicting coal permeability that considered the impacts of water saturation and effective stress was established, revealing the controlled mechanism affecting the permeability change.

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Experimental Investigation of Pore Pressure Effect on Coal Sample Permeability Under Different Temperatures

Meng

Gao

et al. 2022

Nat Resour Res

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Coal-bed methane geology of the No. 2 coal seam in Fengfeng Coalfield, North China

Cited by 7 publications

References 49 publications

Macromolecular Structure Controlling Micro Mechanical Properties of Vitrinite and Inertinite in Tectonically Deformed Coals—A Case Study in Fengfeng Coal Mine of Taihangshan Fault Zone (North China)

Macromolecular Structure Controlling Micro Mechanical Properties of Vitrinite and Inertinite in Tectonically Deformed Coals—A Case Study in Fengfeng Coal Mine of Taihangshan Fault Zone (North China)

Experimental study on water saturation effect on coal sample permeability under different effective stresses

Experimental Investigation of Pore Pressure Effect on Coal Sample Permeability Under Different Temperatures

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