Advanced characterization of pores and fractures in coals by nuclear magnetic resonance and X-ray computed tomography
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- 作者：YanBin Yao (1)
DaMeng Liu (1)
YiDong Cai (1)
JunQian Li (1) - 关键词：coalbed methane ; pore ; fracture ; nuclear magnetic resonance (NMR) ; X ; ray computed tomography (X ; CT)
- 刊名：Science China Earth Sciences
- 出版年：2010
- 出版时间：June 2010
- 年：2010
- 卷：53
- 期：6
- 页码：854-862
- 全文大小：1612KB
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DaMeng Liu (1)
YiDong Cai (1)
JunQian Li (1)
1. School of Energy Resources, China University of Geosciences, Beijing, 100083, China - ISSN：1869-1897
文摘
This paper demonstrates capabilities of low-field nuclear magnetic resonance (NMR) and microfocus X-ray computed tomography (μCT) in advanced, nondestructive, and quantitative characterization of pore types, producible porosity, pore structure, and spatial disposition of pore-fractures in coals. Results show that the NMR transverse relaxation time (T 2) at 0.5-.5, 20-0, and >100 ms correspond to pores of <0.1 μm, >0.1 μm, and fractures, respectively. A much higher T 2 spectrum peak reflects a much better development of pores (or fractures) corresponding to the T 2, and vice versa. Three basic components in coals, i.e., the pores (or fractures), coal matrix, and minerals have their distinctive range of CT numbers. Among these, the CT number of pores is commonly less than 600 HU. The producible porosity, which is a determination of permeability, can be calculated by T 2 cutoff value (T 2C) of coal NMR. The coal pore structure can be efficiently estimated by the newly proposed -em class="a-plus-plus">T 2C based model- Finally, μCT scan was proven capable of modeling and spatial visualization of pores and fractures.