Tracer diffusion coefficients in sedimentary rocks: Correlation to porosity and hydraulic conductivity
Document Type
Article
Date of Original Version
12-1-2001
Abstract
Matrix diffusion is an important transport process in geologic materials of low hydraulic conductivity. For predicting the fate and transport of contaminants, a detailed understanding of the diffusion processes in natural porous media is essential. In this study, diffusive tracer transport (iodide) was investigated in a variety of geologically different limestone and sandstone rocks. Porosity, structural and mineralogical composition, hydraulic conductivity, and other rock properties were determined. The effective diffusion coefficients were measured using the time-lag method. The results of the diffusion experiments indicate that there is a close relationship between total porosity and the effective diffusion coefficient of a rock (analogous to Archie's Law). Consequently, the tortousity factor can be expressed as a function of total porosity. The relationship fits best for thicker samples (>1.0 cm) with high porosities (>20%), because of the reduced influence of heterogeneity in larger samples. In general, these correlations appear to be a simple way to determine tortuosity and the effective diffusion coefficient from easy to determine rock porosity values. Copyright © 2001 Elsevier Science B.V.
Publication Title, e.g., Journal
Journal of Contaminant Hydrology
Volume
53
Issue
1-2
Citation/Publisher Attribution
Boving, Thomas B., and Peter Grathwohl. "Tracer diffusion coefficients in sedimentary rocks: Correlation to porosity and hydraulic conductivity." Journal of Contaminant Hydrology 53, 1-2 (2001): 85-100. doi: 10.1016/S0169-7722(01)00138-3.