%0 Journal Article
%T Structural Characteristics and Physical Properties of Tectonically Deformed Coals
%A Yiwen Ju
%A Zhifeng Yan
%A Xiaoshi Li
%A Quanlin Hou
%A Wenjing Zhang
%A Lizhi Fang
%A Liye Yu
%A Mingming Wei
%J Journal of Geological Research
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/852945
%X Different mechanisms of deformation could make different influence on inner structure and physical properties of tectonically deformed coal (TDC) reservoirs. This paper discusses the relationship between macromolecular structure and physical properties of the Huaibei-Huainan coal mine areas in southern North China. The macromolecular structure and pore characteristics are systematically investigated by using techniques such as X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR), and low-temperature nitrogen adsorption method. The results suggest that under the directional stress, basic structural units (BSU) arrangement is closer, and the orientation becomes stronger from brittle deformed coal to ductile deformed coal. Structural deformation directly influences the macromolecular structure of coal, which results in changes of pore structure. The nanoscale pores of the cataclastic coal structure caused by the brittle deformation are mainly mesopores, and the proportion of mesopores volume in ductile deformed coal diminishes rapidly. So the exploration and development potential of coalbed gas are good in reservoirs such as schistose structure coal, mortar structure coal and cataclastic structure coal. It also holds promise for a certain degree of brittle deformation and wrinkle structure coal of low ductile deformation or later superimposed by brittle deformation. 1. Introduction 1 3 C Tectonically deformed coal (TDC) is a kind of coal in which, under mono- or multiphase tectonic stress fields, its primary texture and structure is significantly destroyed. Tectonic deformation could influence coal macromolecular or deform structure and enhance coalification to a certain degree [1¨C6]. Through structural shearing, graphitization can be facilitated [7, 8]. In fact, tectonic deformation can not only further alter coal¡¯s molecular structure at different degrees but also change the physical properties of reservoirs (such as porosity and permeability). Based on measurement of mercury intrusion, researchers compared micropore features of TDCs collected from different coalfields [9¨C12]. These experiments have indicated that the pore structure of TDCs showed greater medium pores and mesopore volumes than normal undeformed coals, but there was rare difference in micropores between primary structure coals and TDCs. This indicated that structural deformation did not obviously influent micropore structure (less than 10£¿nm in diameter). Meanwhile, the nanoscale pore
%U http://www.hindawi.com/journals/jgr/2012/852945/