LNMR Study on Microstructure Characteristics and Pore Size Distribution of High-Rank Coals with Different Bedding

In order to study the pore structure characteristics of high-rank coals with different bedding, NMR experiments were carried out for high-rank coals with different bedding angles (0 degrees, 30 degrees, 45 degrees, 60 degrees, and 90 degrees). The results show that the distribution of T-2 map of high-rank coal with different bedding is similar to some extent, showing a double peak or triple peak distribution, and the first peak accounts for more than 97% of the total, indicating that small holes are developed in high-rank coal with different bedding, while macropores are not developed. The influence of bedding angle on the fracture proportion is less than 0.3%. Compared with the fracture proportion, the effect of bedding angle on the proportion of microhole, medium hole, and large hole is greater and presents a certain rule. There are certain differences in T-2 cutoff value (T-2C) of high-rank coal with different bedding. The relationship between bedding angle and T-2C conforms to exponential function, and the correlation degree R-2 is 0.839. The research results provide a theoretical basis for gas extraction and utilization and prevention of gas disaster in coal mines in China.

Automated summary

The study revealed that high-rank coals with different bedding angles have developed small pores, with the influence on fracture proportion being minimal, while the effect is greater on the proportion of microholes, medium holes, and large holes, demonstrating a certain pattern.