Physical Characterization of the Pore-Fracture System in Coals, Northeastern China. Issue 2 (March 2013)

• Record Type: Journal Article
• Authors: Li, Junqian; Liu, Dameng; Yao, Yanbin; Cai, Yidong; Guo, Xiaoqian
• Is Part Of: Energy exploration & exploitation. Volume 31:Issue 2(2013)
• Page Start: 267
• Page End: 285
• Publication Date: 2013-03
• Subjects: Open pore-fractures -- Coalbed methane (CBM) -- Mercury porosimetry -- Fractal dimension -- Mercury withdrawal efficiency -- Permeability; Power resources -- Periodicals; 333.79
• DOI: 10.1260/0144-5987.31.2.267
• Languages: English
• ISSNs: 0144-5987

Abstract

Usually mercury intrusion/extrusion curves reflect the characteristics of open pore-fracture system of coals. Using this method, the nature of the open pore-fractures of 18 Chinese coals (varying in vitrinite reflectance from 0.65 to 1.76 % R o, max ) was studied. A quantitative evaluation method for micropore (0-0.1 μm, in diameter), mesopore (0.1-1 μm), macropore (1-10 μm) and fracture (>10 μm) within coals was established by the mercury intrusion curves. The method was verified by the fractal geometry theory. Moreover, three Types (I, II and III) of the open pore-fracture systems of coals were analyzed by combining mercury withdrawal efficiency and permeability with pore size distribution. Results show that (a) Type I coals are characterized by abundant open micropores (mean 62.8 vol. %) and rarely open fractures, which leads to a large minable potential but very low production rate for coalbed methane (CBM); (b) Type II coals have low minable potential and high production rate for CBM, mainly because of the distribution of a few micropores (mean 35.5 vol. %) and a large number fractures (mean 19.7 vol. %) in coals; (c) Type III coals are the most appropriate to exploit CBM due to the existence of optimal open pore-fracture system (micropores, mean 58.5 vol. %; fractures, mean 15.4 vol. %) within coals.