Field-Scale Effective Matrix Diffusion Coefficient for Fractured Rock: Results from Literature Survey.

Zhou, Q. ; Liu, H. ; Molz, F. J. ; Zhang, Y.

Technical Information Center Oak Ridge Tennessee

关键词: Radionuclide migration;    Fractured reservoirs;    Diffusion;    Radiosotopes;    Radioactive wastes;   

RP-ID  :  DE2006859193

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

Matrix diffusion is an important mechanism for solute transport in fractured rock. We recently conducted a literature survey on the effective matrix diffusion coefficient, D(sub m)(sup e) a key parameter for describing matrix diffusion processes at the field scale. Forty field tracer tests at 15 fractured geologic sites were surveyed and selected for the study, based on data availability and quality. Field-scale D(sub m)(sub e) values were calculated, either directly using data reported in the literature or by reanalyzing the corresponding field tracer tests. Surveyed data indicate that the effective-matrix- diffusion-coefficient factor F(sub D) (defined as the ratio of D(sub m)(sub e) to the lab-scale matrix diffusion coefficient (D(sub m)) of the same tracer) is generally larger than one, indicating that the effective matrix diffusion coefficient in the field is comparatively larger than the matrix diffusion coefficient at the rock-core scale. This larger value can be attributed to the many mass-transfer processes at different scales in naturally heterogeneous, fractured rock systems.