Advective Transport in a Synthetic Discrete Fracture System With Internal Variability in Permeability

Particle travel times in a synthetic four-fracture system with and without internal variability in permeability are analyzed. The internal fracture variability is described by three different multivariate normal distributions with identical mean, variance and correlation length but differ in connectivity structure. A recently developed numerical discrete facture network model is used to calculate flow and particle travel times corresponding to advective transport, which are then used to evaluate the relative impact of texture type on particle travel times. Results show that most realizations of the different textures applied to the four-fracture network are consistent with previous studies of these textures applied to porous media, where the texture corresponding to a well-connected structure leads to faster transport. However, we also demonstrate cases when the four-fracture network does not behave as expected and the connected texture leads to slower transport. This behavior is attributed to fracture network effects, which do not exist in porous media or single-fracture representations.