Streamline simulation of Surfactant Enhanced Aquifer Remediation

Abstract

Nonaqueous Phase Liquids (NAPLS) are a recognized source of groundwater contamination. Surfactant Enhanced Aquifer Remediation (SEAR) shows promise in increasing the efficiency and effectiveness over traditional "pump and treat" NAPL remediation processes. Laboratory results are not always consistent with the effects observed in field applications because of the complex interactions that occur in the subsurface. Mathematical modeling is required to enable accurate prediction and understanding of SEAR. This study develops a SEAR computer simulator that is fast, robust, and accurate. The new code applies fractional flow theory in conjunction with streamline theory to predict residual saturation, saturation distribution, production rate and cumulative production histories. The model is three dimensional and capable of modeling heterogeneity anisotropy. The SEAR simulator models mobilization of residual NAPL through the effects of surfactant on the relative permeability curves. The solubilization effects are modeled by constant partition coefficients. The SEAR simulator is compared to a state of the art, high resolution, finite difference simulator (UTCHEM) under a variety of conditions. The predictions of the new SEAR simulator show close agreement with those predicted by UTCHEM. The streamline simulator is orders of magnitude faster than UTCHEM and is ideally suited for screening studies.