Physical properties, vitrinite reflectance, and microstructure of coal, Taiyuan Formation, Qinshui Basin, China
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In this study, we experimentally established the relationship between physical properties, vitrinite reflectance, and microstructure of coal, Taiyuan Formation, Qinshui Basin, China using representative coal samples collected from three different mines via the rock mechanics testing system (MTS). We analyzed the organic macerals, vitrinite reflectance, and microstructure of 11 coal samples using petrography and scanning electron microscopy (SEM). The experimental results suggest that (1) the elastic parameters can be described by linear equations, (2) both P-and S-wave velocities display anisotropy, (3) the anisotropy negatively correlates with vitrinite reflectance, and (4) the acoustic velocities and Young’s modulus are negatively correlated with the volume of micropores. The derived empirical equations can be used in the forward modeling and seismic inversion of physical properties of coal for improving the coal-bed methane (CBM) reservoir characterization.
KeywordsCoal physical properties ultrasonic testing microstructure
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The authors thank Y.M. Shan and M.S. Feng from the State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (Chengdu University of Technology) for their assistance with the ultrasonic testing, thin section analysis, and SEM imaging. The authors also acknowledge the help from colleagues and graduate students in sample collection and preparation. The authors are also indebted to Dr. Bo Zhang of the University of Alabama for his constructive suggestions. Finally, we wish to thank the reviewers for their valuable comments as well as the chief editor Fan Wei-Cui for editing.
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