Regular Article
Diffusion of Water at Low Saturation Levels into Sandstone Rock Plugs Measured by Broad Line Magnetic Resonance Profiling

https://doi.org/10.1006/jcis.1996.0056Get rights and content

Abstract

Broad line magnetic resonance imaging has been used to profile water ingress into a series of well-characterized sandstone rock plugs at saturation levels below the vapor percolation threshold. The diffusion process has been found to be strongly anomalous. Rather, it is in quantitative agreement with a model based on parallel transport of water in the vapor phase and adsorbed on the pore surfaces with the vapor and pore surface water maintained in dynamic local equilibrium. Among other parameters, the analysis has yielded estimates of the surface water diffusion coefficients (mean 5 × 10−6cm2s−1) and of the critical depths of surface water below which the vapor pressure is substantially reduced by strong adsorption (mean 30 molecular layers). A temperature-dependent study of one plug has shown that the pore surface water diffusion is thermally activated and is governed by an Arrhenius rate law with an activation energy of 49 kJ mol−1.

References (0)

Cited by (23)

  • MRI of mass transport in porous media: Drying and sorption processes

    2012, Progress in Nuclear Magnetic Resonance Spectroscopy
    Citation Excerpt :

    Many porous materials can adsorb various vapors and gases. Adsorption of water vapor by the sandstone rock cores of various compositions, porosities and permeabilities at saturation levels below the vapor percolation threshold has been studied using GE with an oscillating gradient [228,258]. The results were modeled based on parallel transport of water in the vapor phase and water adsorbed on the pore walls, with a dynamic local equilibrium between the two phases.

  • NMR spectroscopy in environmental research: From molecular interactions to global processes

    2011, Progress in Nuclear Magnetic Resonance Spectroscopy
    Citation Excerpt :

    Williams and coworkers used MRI to investigate fluid viscosity and rock core plug permeability in Lochaline sandstone [601]. In 1996, McDonald and coworkers used broad line magnetic resonance imaging to profile water ingress into a series of sandstone rock plugs at saturation levels below the vapor percolation threshold [602]. The ability to visualize water and oil in rock plugs is of substantial importance in the modeling of diffusion processes within rock and the subsequent development of enhanced oil recovery techniques from reservoir fields.

  • A quantitative NMR imaging study of mass transport in porous solids during drying

    2000, Chemical Engineering Science
    Citation Excerpt :

    A monograph of Crank (1956) is a very popular reference which provides solutions as well as useful recipes. However, in many cases, including the drying processes in natural and synthetic porous solids, the effective diffusivity is likely to be dependent on the concentration of the diffusing substance (Pel, Ketelaars, Adan & van Well, 1993; Ketelaars, Pel, Coumans & Kerkhof, 1995; McDonald, Pritchard & Roberts, 1996; Pel, Brocken & Kopinga, 1996). Numerical solution of the diffusion equation can be employed in such cases, which makes this straightforward approach time consuming.

  • 9. Nuclear Magnetic Resonance

    1999, Experimental Methods in the Physical Sciences
View all citing articles on Scopus
View full text