Abstract
Some medium rank coal samples (from Dongshan coal mine with the depth of 840 m) and low-rank coal samples (from Yimin coal mine with the depth of 16.44 m) were measured by the overburden porosity test, mercury intrusion porosimetry (MIP) and Low-Temperature Nitrogen Gas Adsorption (LT-N2GA). The results show that the pores and microcracks contents of Dongshan coal samples are less than Yimin coal sample. The adsorption pores with size less than 100 nm and microcracks with size more than 10 μm are dominated in Dongshan coal, but seepage pores with a diameter from 100 nm to 10 μm in Yimin coal. Compared to Yimin coal, Dongshan coal samples have stronger stress sensitivity, higher fracture compressibility, and higher coal matrix compressibility. Based on the MIP data corrected by LT-N2GA, the surface fractal dimensions of adsorption pores, seepage pores, and microcracks in two groups of coal samples were also calculated to investigate pore and microcrack surface roughness. The more the value of fractal dimension is, the higher the roughness is. The results show that the surface roughness of various pores and microcracks are different. The fractal dimensions of adsorption pores, seepage pores, and microcracks in Dongshan coal decrease gradually, while the surface fractal dimension of seepage pores in Yimin coal is highest.
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Data not available due to PetroChina restrictions.
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This research was supported by the PetroChina Company Limited 14th Five Year Plan Science and Technology Major Project (2021DJ2306), the National Nature Science Foundation of China (52074297), the Central University Basic Research Fund of China (2022YJSLJ03) and the key science and technology Project of the PetroChina Company (2022KT0303).
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Sun, B., Zhu, J., Chen, Z. et al. Multiscale pore distribution and evolution characteristic of medium/low-rank coal. Arab J Geosci 15, 1743 (2022). https://doi.org/10.1007/s12517-022-11019-z
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DOI: https://doi.org/10.1007/s12517-022-11019-z