PORE-SIZE DISTRIBUTIONS AND TORTUOSITY IN HETEROGENEOUS POROUS-MEDIA
PORE-SIZE DISTRIBUTIONS AND TORTUOSITY IN HETEROGENEOUS POROUS-MEDIA
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DOI：
10.1006/jmra.1995.1012
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发表时间：
1995-01-01
期刊：
影响因子：
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通讯作者：
SOTAK, CH
中科院分区：
文献类型：
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作者：
LATOUR, LL;KLEINBERG, RL;SOTAK, CH
通过脉冲保持梯度核磁共振在长时间观察下测量的扩散系数原则上可用于估计多孔介质的弯曲度。这种方法对于玻璃球填充物很有用，但我们发现它通常不适用于多孔沉积岩。天然沉积岩的特点是具有复杂的微观几何形状和广泛的孔径分布，在实验可观测的时间内无法通过扩散分子对其进行充分采样。对于孔隙非常大的岩石，随时间变化的扩散系数 D(t) 可能明显不规则。在非均质多孔介质中，通过弛豫时间测量确定孔径分布和通过 PFG 扩散测量确定弯曲度是相互排斥的。 (C) 1995 学术出版社
The diffusion coefficient, measured at long observation times by pulsed-held-gradient NMR, can in principle be used to estimate the tortuosity of a porous medium. This method is useful for glass-sphere packs, but we find that it does not generally work for porous sedimentary rock. Natural sedimentary rocks are characterized by complex microgeometries and broad distributions of pore sizes, which cannot be adequately sampled by diffusing molecules in experimentally accessible observation times. The time-dependent diffusion coefficient D(t) can be distinctly irregular for rocks with very large pores. In heterogeneous porous media, determination of pore-size distribution by relaxation-time measurements and tortuosity by PFG diffusion measurements are mutually exclusive. (C) 1995 Academic Press, Inc.