Matrix Diffusion Model Research Articles

Discrete Fracture Network Modelling of Tracer Migration Experiments at the Kamaishi Mine

AbstractThis paper presents the results of a discrete fracture network modelling for the non-sorbing tracer migration experiments, which were conducted in the fractured rock at the Kamaishi mine. A newly developed in-plane heterogeneity model, which can address the channelling effects within a fracture, and the matrix diffusion model, which can simulate the retardation time due to the matrix diffusion adjacent to fracture were applied in this study. As a result, the matrix diffusion model better reproduces the general shape of breakthrough curves. The transport aperture At was approximately one order of magnitude larger than the hydraulic aperture Ac derived from the cubic law.

Channeling and Fickian Dispersion in fractal simulated porous media

We simulate tracer transport in a two‐dimensional porous medium. We provide justification for the use of a fractal scaling law to characterize the spatial variability of rock properties, leading to a fractal rock property model. A methodology based on the fractal model discussed is applied to experimental data to generate a “fractal porous medium” and to solve the associated flow and tracer transport problems. Tracer breakthrough curves are computed for three different breakthrough distances. An advection‐dispersion matrix diffusion model, a channeling model, and a channel‐network model are used to assess objectively the relative contributions of Fickian dispersal processes and channeling within simulated tracer transport through the fractal medium. The results reveal early breakthrough is fast‐channel dominated, while later breakthrough is predominately Fickian.