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The Scientific World Journal
Volume 2014, Article ID 560450, 13 pages
Research Article

Characterization of Coal Porosity for Naturally Tectonically Stressed Coals in Huaibei Coal Field, China

1Key Laboratory of Computational Geodynamics, Chinese Academy of Sciences, College of Earth Science, University of Chinese Academy of Sciences, Beijing 100049, China
2State Key Laboratory of Petroleum Resource and Prospecting, China University of Petroleum, Beijing 102249, China
3PetroChina Research Institute of Petroleum Exploration & Development, Key Lab of Basin Structure and Petroleum Accumulation, Beijing 100083, China

Received 3 March 2014; Revised 30 May 2014; Accepted 17 June 2014; Published 10 July 2014

Academic Editor: Santiago Garcia-Granda

Copyright © 2014 Xiaoshi Li et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The enrichment of coalbed methane (CBM) and the outburst of gas in a coal mine are closely related to the nanopore structure of coal. The evolutionary characteristics of 12 coal nanopore structures under different natural deformational mechanisms (brittle and ductile deformation) are studied using a scanning electron microscope (SEM) and low-temperature nitrogen adsorption. The results indicate that there are mainly submicropores (2~5 nm) and supermicropores (<2 nm) in ductile deformed coal and mesopores (10~100 nm) and micropores (5~10 nm) in brittle deformed coal. The cumulative pore volume (V) and surface area (S) in brittle deformed coal are smaller than those in ductile deformed coal which indicates more adsorption space for gas. The coal with the smaller pores exhibits a large surface area, and coal with the larger pores exhibits a large volume for a given pore volume. We also found that the relationship between S and V turns from a positive correlation to a negative correlation when  m2/g, with pore sizes <5 nm in ductile deformed coal. The nanopore structure (<100 nm) and its distribution could be affected by macromolecular structure in two ways. Interconversion will occur among the different size nanopores especially in ductile deformed coal.