Probing porous media with gas diffusion NMR
R W Mair1, G P Wong, D Hoffmann
1Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA.
Physical Review Letters
|September 7, 2001
Summary
Gas diffusion nuclear magnetic resonance (GD-NMR) effectively measures porous media structure. This technique accurately quantines surface-area-to-volume ratio and tortuosity in various materials, including rocks.
Area of Science:
- Geophysics
- Materials Science
- Physical Chemistry
Background:
- Characterizing porous media is crucial for understanding transport properties.
- Nuclear Magnetic Resonance (NMR) offers non-invasive probing capabilities.
- Gas diffusion NMR (GD-NMR) is an emerging technique for materials analysis.
Purpose of the Study:
- To demonstrate the efficacy of GD-NMR for analyzing porous media structure.
- To quantify key structural parameters like surface-area-to-volume ratio and tortuosity.
- To validate GD-NMR performance across different material types.
Main Methods:
- Utilized laser-polarized and thermally polarized xenon gas.
- Applied GD-NMR spectroscopy to random packs of glass beads.
- Analyzed sandstone and complex carbonate rock samples.
Main Results:
- GD-NMR accurately determined the surface-area-to-volume ratio (S/V rho) in glass bead packs.
- GD-NMR precisely measured the tortuosity (alpha) in glass beads, correlating with transport properties.
- GD-NMR provided reliable tortuosity measurements for sandstone and carbonate rocks.
Conclusions:
- GD-NMR is a powerful and versatile technique for probing porous media.
- The method accurately quantifies critical structural and transport-related parameters.
- GD-NMR shows significant potential for diverse geological and material science applications.
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