MONTE-CARLO SIMULATION OF CONTAMINANT TRANSPORT - II - MORPHOLOGICAL DISORDER IN FRACTURE CONNECTIVITY

Simulating contaminant transport in fractured geologic media is challe nging. Aside from the difficulties encountered in properly modeling th e heterogeneities in the hydraulic properties of the fractures and the matrix, it is difficult to quantify and model the disorder in the fra cture connectivity. Correct prediction of the spread of contaminants i n fractured geologic media is not possible without considering this in herent morphological disorder. Here, we develop a network model of fra ctures, and use the model to study transport of contaminants. We inves tigate the influence of morphology on the transport process by introdu cing disorder in the fracture connectivity through a novel percolation scheme. The network close to the percolation threshold is very comple x and allows the contaminant particles to follow many slow paths. This closely captures the physical situation. We show, how the disorder in the network changes the residence time distributions and its various temporal moments. We also show how the residence time distribution and the temporal moments are influenced by the interaction of the disorde r with the various transport mechanisms, such as convection. dispersio n, adsorption, and first-order decay.