Transport simulation in porous fractured rock using random walk particle tracking and the analytic element method

Abstract

Concerns about the water and soil quality, long-term impact of industrial and agricultural activities, and nuclear an chemical waste repositories demand the understanding of solute transport in fractured porous rock formations. Accurate numerical simulations of such phenomena is fundamental on the development of this understanding. Given the complexities associated with ow and transport in fractured porous formations, a robust numerical method both for the ow and transport simulation should be employed. Random Walk Particle Tracking is an established method for simulation of solute transport, and is particularly effective when the advective component is large, as is the case with ow in porous fractured formations. But for an efficient use of random walk transport simulation, the oweld must be known in all points of the domain. The Analytic Element Method satisfies this condition, as its solution for the ow eld is given by the superposition of analytic functions, and no mesh or discretization of the domain is necessary. New advancements in the random walk simulations, as simulation of non-Fickian, reactive solutes and time domain techniques, together with the recent development of the analytic element for fractures for the Analytic Element Method, provide an excelent combination to accurately simulate transport in fractured porous formations. The characteristics of both methods allow the development of a parallel simulation framework, which in turn can simulate large domains/large number of particles with high precision. The development of a computational tool that combines the Analytic Element Method solutions for fractures and a parallel framework for the transport simulation using random walk particle tracking for large domains/large number of particles is the main goal of this project. This computational tool is valuable to the hydrogeologist, allowing the understanding and simulation of contamination and transport in fractured aquifers. (AU)