Viscous Effects in Pore Scale Modeling of Immiscible Fluid Flow Through Porous Media

摘要

Sites contaminated with dense nonaqueous phase liquids (DNAPLs) such as chlorinated solvents are, typically, exceptionally difficult to characterize because the unstable nature of the front results in complex distributions that are erratic, highly fingered and sensitive to small-scale heterogeneities. However, DNAPL source zone characterization is important for risk assessments, feasibility studies and identification of appropriate remediation technologies at DNAPL-contaminated sites. The extent and configuration of the source zone is also important input to multiphase mass transfer models. Pore scale models capture the essential physics of the multiphase migration process without the need to solve the large systems of equations inherent in continuum modeling. This research project developed a modified diffusion limited aggregation model that can be used to predict source zone geometry when viscous effects are important. A unique relationship between the model input parameter, the sticking probability and the essential properties governing the DNAPL-water front displacement was developed. The model was compared with both homogeneous and heterogeneous laboratory experiments. Model and laboratory results were found to compare well.