Surface nuclear magnetic relaxation and dynamics of water and oil in macroporous media
Surface nuclear magnetic relaxation and dynamics of water and oil in macroporous media
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DOI：
10.1103/physreve.64.021605
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发表时间：
2001-08-01
影响因子：
2.4
通讯作者：
Bryant, RG
中科院分区：
文献类型：
--
作者：
Godefroy, S;Korb, JP;Bryant, RG
对水或油饱和颗粒填料和石灰岩的质子核自旋弛豫研究可以估计表面分子动力学参数。在不同的温度、磁场强度和孔径条件下进行了测量。我们通过低场核磁共振弛豫表明，改变表面顺磁杂质的数量会导致孔隙中液体弛豫时间T-1和T-2的不同孔径依赖性。表面限制或扩散限制弛豫模型很好地支持了这些依赖关系。表面弛豫参数rho(1)和rho(2)是根据表面限制条件下的孔径依赖性推导出来的。我们通过场循环核磁共振弛豫和相关的理论模型证明了表面弛豫rho(1)的频率和温度依赖性。发现的典型频率依赖关系允许在多孔介质中分离表面和体微动力学。因此，确定了几个表面动力学参数，如扩散系数、活化能、停留时间和表面亲和系数。本文提出的方法对承压流体的表面微动力学进行了有力的分析，可应用于含油岩石的研究。
Proton nuclear spin-relaxation studies on water- or oil-saturated granular packings and limestone rocks allow estimating surface molecular dynamical parameters. Measurements were performed at various conditions of temperature, magnetic field strengths, and pore size. We show by low field NMR relaxation that changing the amount of surface paramagnetic impurities leads to striking different pore-size dependences of the relaxation times T-1 and T-2 of liquids in pores. These dependences are well supported by surface-limited or diffusion-limited relaxation models. Surface relaxivity parameters rho (1) and rho (2) are deduced from the pore-size dependence in the surface-limited regime. We evidence the frequency and temperature dependence of the surface relaxivity rho (1) by field cycling NMR relaxation and relevant theoretical models. The typical frequency dependence found allows an experimental separation of the surface and bulk microdynamics in porous media. Several surface dynamical parameters, such as diffusion coefficients, activation energies, time of residence, and coefficient of surface affinity, were therefore determined. The methods presented here give a powerful analysis of the surface microdynamics of confined liquids, which can be applied to the study of oil-bearing rocks.