EFFECT OF PERMEABILITY AND POROSITY CONDITIONING ON THE PREDICTION OF DENSE CHLORINATED SOLVENT MIGRATION PATTERNS IN A HIGHLY CHARACTERIZED FLUVIAL AQUIFER

The 3D multiphase compositional model CompFlow is applied to simulate in detail the movement of DNAPL released in an exceptionally well characterized, highly heterogeneous fluvial aquifer. In addition, the migration patterns of the aqueous phase plume arising from the dissolution of DNAPL source are examined in detail. Using a variety of field and laboratory techniques that include permeability, porosity and sorption measurements, georader surveys and modern tomographic investigations, researchers at the University of Tübingen, Germany performed an intense characterization study along six parallel cross sections in an outcrop, thus revealing the 3D structure of the fluvial deposits. The aquifer analog is reconstructed in three dimensions from the data using two alternative conditional geostatistical approaches, each with different degrees of conditioning. One method employs the transition probability/Markov chain approach while the other involves a traditional variogram analysis of the data along with the application of kriging. Spatial cross-correlations and the geologic interpretation of facies architecture are involved in the transition probability modeling approach. This includes the proportion of each geologic material, and the geometries and juxtapositioning of facies assemblages. The predicted geometry of the DNAPL source zone, the character of the aqueous-phase plume and the concentrations and mass fluxes crossing a down-gradient compliance boundary will be compared and evaluated for each aquifer reconstruction using the different methodologies and for the various levels of conditioning.