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Environmental Sciences

Coal Geology & Exploration

Pore structure

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Full-Text Articles in Engineering

Exploring The Pore Structure Of Reconstructed Soils And Its Effects On Water And Salt Transport Based On Ct Scanning, Li Huakun, Zheng Liugen, Chen Yongchun, Li Bing, Tao Pengfei, Li Hao Apr 2024

Exploring The Pore Structure Of Reconstructed Soils And Its Effects On Water And Salt Transport Based On Ct Scanning, Li Huakun, Zheng Liugen, Chen Yongchun, Li Bing, Tao Pengfei, Li Hao

Coal Geology & Exploration

Coal gangue serves as a critical material for landfilling and reclamation in the subsidence areas of coal mines. However, due to its rough textures and poor water-holding capacity, soils reconstructed using coal gangue exhibit somewhat different pore structures and water-salt transport from undisturbed soils. To explore the changes in the pore structure of the reconstructed soils and their effects on water and salt transport, this study analyzed the differences in the pore structures between four samples from undisturbed soils, the overburden, mud-gangue mixtures, and gangue using CT scanning and image analysis. Furthermore, an indoor experimental device was designed to simulate …


Gas Expansion Energy Of Coals With Different Metamorphic Degrees: Evolutionary Characteristics And Their Implications For The Outburst Prediction, Liu Gaofeng, Li Baolin, Zhang Zhen, Liu Huan, Guan Wenbo, Si Nian Oct 2023

Gas Expansion Energy Of Coals With Different Metamorphic Degrees: Evolutionary Characteristics And Their Implications For The Outburst Prediction, Liu Gaofeng, Li Baolin, Zhang Zhen, Liu Huan, Guan Wenbo, Si Nian

Coal Geology & Exploration

To achieve an elevated accuracy in the prediction of coal and gas outbursts, this study conducted mercury injection capillary pressure (MICP) tests and isotherm adsorption experiments on selected six coal samples with different metamorphic degrees. Furthermore, it calculated the gas expansion energy of coals and analyzed the evolutionary characteristics of the gas expansion energy of coals with different metamorphic degrees, as well as their relationships with the prediction indices of coal and gas outbursts. The results of this study are as follows: (1) The differences in the pore structures and adsorptivity of coals with different metamorphic degrees led to different …


Reliability Analysis And Compressibility Correction Of Mercury Intrusion Porosimetry Experiments For Low-Medium-Rank Coals, Song Dangyu, Zhao Yuwei, Li Yunbo, Yu Zhen May 2023

Reliability Analysis And Compressibility Correction Of Mercury Intrusion Porosimetry Experiments For Low-Medium-Rank Coals, Song Dangyu, Zhao Yuwei, Li Yunbo, Yu Zhen

Coal Geology & Exploration

Low-medium-rank coals are soft and exhibit significant compressibility under high pressure. Therefore, it is debatable whether the pore structure of low-medium-rank coals can be reliably determined using mercury intrusion porosimetry (MIP) experiments. In this study, MIP experiments were conducted on four samples of low-medium-rank coals. By comparing the mercury injection curves of samples with different particle sizes, as well as the macroscopic and microscopic characteristics of the samples before and after mercury injection, this study established a correction method for the mercury injection volume at the high-pressure stage and investigated the reliability of MIP experiments in determining the pore structure …


Influencing Mechanisms Of Sc-Co2 Extraction On The Microstructures Of High-Rank Tectonic Coals, Zhang Xiaodong, Zhang Yu, Zhang Shuo, Li Guizhong, Li Xianzhong May 2023

Influencing Mechanisms Of Sc-Co2 Extraction On The Microstructures Of High-Rank Tectonic Coals, Zhang Xiaodong, Zhang Yu, Zhang Shuo, Li Guizhong, Li Xianzhong

Coal Geology & Exploration

This study aims to reveal the influencing patterns of supercritical CO2 (SC-CO2) on the microstructures of tectonic coals during the injection of CO2 into deep coal seams. The study conducted SC-CO2 extraction experiments on two types of high-rank coal samples with different damage degrees, namely the lean coal samples from the Daping coal mine in Shanxi Province and the anthracite samples from the Zhenxing coal mine in Guizhou Province. Accordingly, this study compared the parameters of pore structures and aromatic carbon stacking structures in the coal samples before and after the extraction experiments. Finally, this …


Nanopore Structure And Surface Roughness In Brittle Tectonically Deformed Coals Explored By Atomic Force Microscopy, Zhang Ningyuan, Yao Suping May 2022

Nanopore Structure And Surface Roughness In Brittle Tectonically Deformed Coals Explored By Atomic Force Microscopy, Zhang Ningyuan, Yao Suping

Coal Geology & Exploration

The pore structure of coal is the key to coalbed methane (CBM) exploration and exploitation, and coal mining safety. Compared to primary coals, tectonically deformed coals (TDCs) have stronger heterogeneity and are of great importance in coal reservoir study. Here, the pore structure and surface roughness of brittle TDCs were obtained with atomic force microscopy (AFM) and NanoScope Analysis and Gwyddion software. The results show that tectonic deformation generally promotes the pore development in brittle TDCs, but the extent of tectonic impact varies greatly among different brittle TDCs. As a result, two stages in brittle TDCs were identified: weak brittle …


Qualitative-Quantitative Multi Scale Characteristics Of Shale Pore Structure From Upper Paleozoic Coal-Measures In Linxing Area, Liu Cheng, Ding Wangui, Zhang Jian, Chen Xin, Wu Peng, Liu Xueqing, Li Yangbing, Ma Litao, Hu Weiqiang, Kong Wei, Li Yong Dec 2021

Qualitative-Quantitative Multi Scale Characteristics Of Shale Pore Structure From Upper Paleozoic Coal-Measures In Linxing Area, Liu Cheng, Ding Wangui, Zhang Jian, Chen Xin, Wu Peng, Liu Xueqing, Li Yangbing, Ma Litao, Hu Weiqiang, Kong Wei, Li Yong

Coal Geology & Exploration

In order to reveal the micro-pore structure characteristics of marine-continental transitional shale and its main controlling factors in the eastern margin of Ordos Basin, and to enrich the understanding of pore development characteristics and pore structure of marine-continental transitional coal-bearing shale in the block, scanning electron microscope, high-pressure mercury injection and liquid nitrogen adsorption analysis were used to characterize the micro-pore structure characteristics of shale in Linxing area. Furthermore, porosity, total content of organic carbon, mineral content, clay relative content and organic matter maturity were tested to study the main controlling factors of development of shale pore structure. The results …


Effect Of Load On Adsorption Characteristics Of Remolded Coal, Dai Juhua, Wang Zhaofeng, Li Xuechen, Li Yanfei, Yue Jiwei Jun 2021

Effect Of Load On Adsorption Characteristics Of Remolded Coal, Dai Juhua, Wang Zhaofeng, Li Xuechen, Li Yanfei, Yue Jiwei

Coal Geology & Exploration

In view of the difficulty in preparing the coal with broken soft structure intact, it needs to be processed into remolded coal. In order to study the influence of suppression loads on the physical characteristics of coal, the micro-pore structure and adsorption characteristics of remolded coal under different molding loads were discussed based on the pore test experiment of low temperature liquid nitrogen and the methane adsorption experiment of high pressure capacity method. The results show that: The pore volume of micropores and pores decreases slightly with the increase of molding load, the specific surface area increases slightly with the …


Experimental Study On Multi-Scale Pore Structure Characteristics Of Tar-Rich Coal In Yushenfu Mining Area, Shen Yanjun, Wang Xu, Zhao Chunhu, Wang Shengquan, Guo Chen, Shi Qingmin, Ma Wen Jun 2021

Experimental Study On Multi-Scale Pore Structure Characteristics Of Tar-Rich Coal In Yushenfu Mining Area, Shen Yanjun, Wang Xu, Zhao Chunhu, Wang Shengquan, Guo Chen, Shi Qingmin, Ma Wen

Coal Geology & Exploration

Extracting oil and refining gas from oil-rich coal is an important measure to make up for the shortage of oil and gas supply in China. The research on pore development characteristics and permeability of tar-rich coal will help to better develop and utilize tar-rich coal. Taking the tar-rich coal in Yushenfu mining area as the research object, this paper studies the multi-scale pore structure and the whole segment pore characterization of tar-rich coal by such methods as low-temperature liquid nitrogen adsorption, mercury intrusion porosimetry, nuclear magnetic resonance and gas permeability measurement method. Based on the test results of multi-scale pore …


Characteristics Of Shale Gas Reservoir In Upper Paleozoic Coal Measures In Yangquan Block, Qinshui Basin, Li Yangyang, Li Xianqing, Zhang Xueqing, Xiao Xianming, Yu Zhenfeng, Wang Baoyu Apr 2021

Characteristics Of Shale Gas Reservoir In Upper Paleozoic Coal Measures In Yangquan Block, Qinshui Basin, Li Yangyang, Li Xianqing, Zhang Xueqing, Xiao Xianming, Yu Zhenfeng, Wang Baoyu

Coal Geology & Exploration

Shale reservoir characteristics are the basic content of shale gas storage capacity evaluation. In order to explore the properties of high-evolved coal-measures shale gas reservoirs and optimize favorable reservoirs, various experimental methods of rock pyrolysis, X-ray diffraction, scanning electron microscopy, high-pressure mercury intrusion, low-temperature N2 and CO2 gas adsorption were applied to the Qinshui Basin. Reservoir characteristics were studied with core samples of coal-measure shale core from the Upper Paleozoic in Yangquan Block. The results show that the Upper Paleozoic coal-measures shale in Yangquan Block of the Qinshui Basin has a high content of organic carbon(average TOC is …


The Characteristics Of Pore Structure And Gas Adsorption For Water-Immersion Coal After Drying, Si Leilei, Xi Yujun, Wang Hongyang, Wen Zhihui, Wei Hpuwjp@163.Com Jianping Feb 2021

The Characteristics Of Pore Structure And Gas Adsorption For Water-Immersion Coal After Drying, Si Leilei, Xi Yujun, Wang Hongyang, Wen Zhihui, Wei Hpuwjp@163.Com Jianping

Coal Geology & Exploration

In order to investigate the characteristics of pore structure and methane adsorption for water-immersion coal after drying, two coal samples with different ranks were soaked in distilled water for a long time(60 d). Then, the low-temperature N2 adsorption experiments and CO2 adsorption experiments were carried out to investigate the changing rules of pore structure for coal before and after water immersion, and the high-pressure capacity method was used to test the characteristics of methane adsorption. Results showed that the pore volume and specific surface area of coal decreased after water immersion. According to the results of low-temperature N …


Micro-Pore Structure And Fractal Characteristics Of Terrestrial Shales: A Case Study Of Shahezi Formation In Xujiaweizi Fault Depression, Lin Zizhi, Lu Shuangfang, Chang Xiangchun, Li Junqian, Zhang Pengfei, Zhou Nengwu, Zhang Yu, Wang Junjie, Huang Hongsheng Feb 2021

Micro-Pore Structure And Fractal Characteristics Of Terrestrial Shales: A Case Study Of Shahezi Formation In Xujiaweizi Fault Depression, Lin Zizhi, Lu Shuangfang, Chang Xiangchun, Li Junqian, Zhang Pengfei, Zhou Nengwu, Zhang Yu, Wang Junjie, Huang Hongsheng

Coal Geology & Exploration

The pore structure and fractal characteristics of shale are analyzed, and their impacting factors are also revealed using the low temperature nitrogen adsorption-desorption method, combined with scanning electron microscopy, C-S analysis and XRD. The results showed that the mineral compositions of Shahezi Formation continental shales were dominated by clay minerals, quartz and feldspar. The pore types in shales were mainly clay mineral intragranular pores, feldspar dissolution pores and grain edge pore, while the organic pores were not developed. The adsorption isotherms of shales belonged to the type Ⅳ isotherm according to the IUPAC, which develop two types of hysteresis loop, …


Numerical Simulation Of Pore Structure Stress Characteristics Of Coal And Rock Mass, Wang Gang, Jiang Chenghao, Chen Xuechang Feb 2021

Numerical Simulation Of Pore Structure Stress Characteristics Of Coal And Rock Mass, Wang Gang, Jiang Chenghao, Chen Xuechang

Coal Geology & Exploration

In order to explore the stress distribution around the pores of coal and rock mass under different loading modes, the skeleton model of coal and rock mass with different pore shapes was constructed through CT three-dimensional reconstruction technology, and uniaxial and triaxial compression experiment simulations were conducted using ABAQUS software. The results showed that under uniaxial compression, the upper and lower regions of spherical pores showed tensile stress concentration, while the left and right regions showed compressive stress concentration. The stress concentration types in the long and short axis of elliptic pores were distinct with different dip angles. Under uniaxial …


Micro Ct-Based Meticulous Characterization Of Porosity Evolution Of Coal In The Process Of Biodegradation, Dong Zhiwei, Guo Hongyu, Xia Daping, Liu Xile, Bai Yang, Zhao Guojun Oct 2019

Micro Ct-Based Meticulous Characterization Of Porosity Evolution Of Coal In The Process Of Biodegradation, Dong Zhiwei, Guo Hongyu, Xia Daping, Liu Xile, Bai Yang, Zhao Guojun

Coal Geology & Exploration

To explore the bio-permeability enhancing effect via methanogen treatment on different rank coals after anaerobic fermentation, micro-CT was used to analyze the change characteristics of pore structure of coal before and after biodegradation. At the same time, the adsorption characteristics of methanogens on the coal surface after anaerobic biodegradation were observed by scanning electron microscopy to analyze the reasons for the effect difference of biological transformation of different rank coals. The results show that the porosity and total throat length of the coal samples biodegraded increase and the connectivity of the pores is enhanced, it is indicated that coal samples …


Shale Gas Potential Of Yanguanjie Formation And Longtan Formation In Central And Southeastern Hunan Province, Cao Taotao, Deng Mo, Liu Hu, Huang Yanran, Stefan Andrew Hurssthouse Aug 2019

Shale Gas Potential Of Yanguanjie Formation And Longtan Formation In Central And Southeastern Hunan Province, Cao Taotao, Deng Mo, Liu Hu, Huang Yanran, Stefan Andrew Hurssthouse

Coal Geology & Exploration

In order to reveal the shale gas potential and exploration direction of the marine-continental transitional shale in central and southeastern Hunan, samples were collected from the Lower Carboniferous Yanguanjie Formation and Upper Permian Longtan Formation, measurements were conducted on TOC, Rran, kerogen carbon isotope, maceral composition, X-ray diffraction, scanning electron microscopy, porosity, permeability and methane sorption capacity. The results indicate that Yanguanjie Formation and Longtan Formation shale are at the mature stage, and mainly dominated by type Ⅲ kerogen. The Longtan shale generally has higher TOC content, while Yanguanjie shale has usually low TOC content. The minerals are …