Meikuang Anquan (Jun 2022)
Study on difference of pore structure in macroscopic coal rock composition based on mercury intrusion method
Abstract
In order to study the pore structures and their difference of different macroscopic coal rocks, eight groups of coal samples from Huanglong Coalfield and Jincheng Mining Area were collected, and the difference of pore structure between vitrain and durain was studied by mercury intrusion test and fractal theory. The results of the study show that the difference in the shape of mercury pressure curves between vitrain and durain is obvious. Compared with durain, vitrain has the characteristics of low mercury saturation and displacement pressure, high mercury removal efficiency and median pressure. Vitrain has the characteristics of macropores and micro-cracks development and good pore sorting characteristics. The pore shape is mainly semi-closed and has strong permeability, but the connectivity between macropores and transition is poor. The pore structure of durain has a large average pore diameter, especially the diffusion pores around 200 nm are relatively developed, which makes the pores between the macropores pores and the transition pores have good connectivity, and the pore shape is mainly open type with strong diffusion ability. The fractal dimension D2 of the durain is higher than that of the vitrain in general, which shows that the large-scale pore structure of the durain is more complex than that of the vitrain. The mutual layered structure of the two coals in the coal seam is more conducive to enhance the pore connectivity and improve the ability of desorption, diffusion and seepage in the coal seam.
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