skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Effects of Spatially Heterogeneous Porosity on Matrix-Diffusion as Investigated by X ray Absorption Imaging

Abstract

Laboratory experiments were performed to investigate the effects of spatial variation in porosity on matrix-diffusion processes. Four centimeter-scale slabs of Culebra dolomite taken from the Waste Isolation Pilot Plant site were used in the tests. Experiments involved the simple diffusion of iodine into a single edge of each rock slab while X ray absorption imaging was used to measure the resulting two-dmensional solute concentration field as a function of time. X ray imaging was also used to quantify the two-dimensional porosity field of each rock slab. Image analysis provided a unique opportunity to both visuake and quantifj the effects of the spatially variable porosi~ on matrixdMusion. Four key results were obtained. First, significant variation in rates of diffusion were realized over the relatively small length (centimeter) and time scales (months) investigated. Second, clear evidence of diffusion preferentially following zones of relatively higher porosity was noted. Third, rate of difhion was found to vary as tracer diffused into the rock slabs encountering changing porosity conditions. Fourth, strong correlation between porosi~ and the calculated diffusion coefficients was found. In fact, the nature of the correlation can be related to the geometry, position, and orientation of the heterogeneous porosity features populating each rockmore » slab.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1093
Report Number(s):
SAND98-1023J
ON: DE00001093
DOE Contract Number:  
AC04-94AL85000
Resource Type:
Journal Article
Journal Name:
Journal of Contaminate Hydrology
Additional Journal Information:
Journal Name: Journal of Contaminate Hydrology
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; X-Ray Radiography; Porous Materials; WIPP; Dolomite

Citation Formats

Boney, C, Christian-Frear, T, Meigs, L C, and Tidwell, V C. Effects of Spatially Heterogeneous Porosity on Matrix-Diffusion as Investigated by X ray Absorption Imaging. United States: N. p., 1998. Web.
Boney, C, Christian-Frear, T, Meigs, L C, & Tidwell, V C. Effects of Spatially Heterogeneous Porosity on Matrix-Diffusion as Investigated by X ray Absorption Imaging. United States.
Boney, C, Christian-Frear, T, Meigs, L C, and Tidwell, V C. 1998. "Effects of Spatially Heterogeneous Porosity on Matrix-Diffusion as Investigated by X ray Absorption Imaging". United States. https://www.osti.gov/servlets/purl/1093.
@article{osti_1093,
title = {Effects of Spatially Heterogeneous Porosity on Matrix-Diffusion as Investigated by X ray Absorption Imaging},
author = {Boney, C and Christian-Frear, T and Meigs, L C and Tidwell, V C},
abstractNote = {Laboratory experiments were performed to investigate the effects of spatial variation in porosity on matrix-diffusion processes. Four centimeter-scale slabs of Culebra dolomite taken from the Waste Isolation Pilot Plant site were used in the tests. Experiments involved the simple diffusion of iodine into a single edge of each rock slab while X ray absorption imaging was used to measure the resulting two-dmensional solute concentration field as a function of time. X ray imaging was also used to quantify the two-dimensional porosity field of each rock slab. Image analysis provided a unique opportunity to both visuake and quantifj the effects of the spatially variable porosi~ on matrixdMusion. Four key results were obtained. First, significant variation in rates of diffusion were realized over the relatively small length (centimeter) and time scales (months) investigated. Second, clear evidence of diffusion preferentially following zones of relatively higher porosity was noted. Third, rate of difhion was found to vary as tracer diffused into the rock slabs encountering changing porosity conditions. Fourth, strong correlation between porosi~ and the calculated diffusion coefficients was found. In fact, the nature of the correlation can be related to the geometry, position, and orientation of the heterogeneous porosity features populating each rock slab.},
doi = {},
url = {https://www.osti.gov/biblio/1093}, journal = {Journal of Contaminate Hydrology},
number = ,
volume = ,
place = {United States},
year = {Tue Oct 20 00:00:00 EDT 1998},
month = {Tue Oct 20 00:00:00 EDT 1998}
}