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Updated: May 11, 2026

In Situ Monitoring of Diffusion of Guest Molecules in Porous Media Using Electron Paramagnetic Resonance Imaging
Published on: September 2, 2016
Superdispersion in homogeneous unsaturated porous media using NMR propagators
1Université d'Avignon et des Pays de Vaucluse, UMR 1114 EMMAH, 84018, Avignon, France.
Abstract:
The NMR propagator technique allows the measurements of the variance σ(2)=<(ξ-<ξ>)(2)> of the displacements as a function of time t when flowing in a porous media. The time dependence of σ is a very sensitive test of Gaussian behavior compared to the analysis of the shape of the propagators. Superdispersion occurs when σ(2)[proportionality]t(α) with the exponent α larger than 1. In a homogeneous 30-μm grain pack and 10 < Pe < 35, we observed weak superdispersion in saturated conditions (α = 1.17) and gradually strong superdispersion as the water saturation decreases (up to α = 1.5) during steady-state oil-water two-phase flow. In saturated conditions, the corresponding longitudinal propagators and breakthrough curves are Gaussian or nearly Gaussian, whereas in two-phase conditions, the longitudinal propagators are nonsymmetric and the breakthrough curves show a tail at long times.
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