Submitted to: Journal of Contaminant Hydrology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/19/2005
Publication Date: 3/10/2005
Citation: O'Carroll, D.M., Abriola, L.M., Polityka, C.A., Bradford, S.A., Demond, A.H. 2005. Prediction of two-phase capillary pressure-saturation relationships in fractional wettability systems. Journal of Contaminant Hydrology. 77:247-270. Interpretive Summary: Simulation of water and organic liquids, such as oil and solvents, through soils requires accurate knowledge of the relationship between fluid pressures and saturation. This work presents a new model to predict these relations for soils that consist of different chemical fractions. The proposed model is based upon fundamental scaling principles that requires relatively few and physically based input parameters, and is applicability to a broad range of soil types. The model provided a reasonable characterization of published data, and holds promise for field application.
Technical Abstract: Capillary pressure/saturation data are often difficult and time consuming to measure, particularly for non-water-wetting soils. Few capillary pressure/saturation predictive models, however, have been developed or verified for the range of wettability conditions that may be encountered in the natural subsurface. This work presents a new two-phase capillary pressure/saturation model for application to the prediction of primary drainage and imbibition relations in fractional wettability media. This new model is based upon an extension of Leverett scaling theory. Analysis of a series of DNAPL/water experiments, conducted for a number of water/ intermediate and water/organic fractional wettability systems, reveals that previous models fail to predict observed behavior. The new Leverett-Cassie model, however, is demonstrated to provide good representations of these data, as well as those from two earlier fractional wettability studies. The Leverett-Cassie model holds promise for field application, based upon its foundation in fundamental scaling principles, its requirement for relatively few and physically based input parameters, and its applicability to a broad range of wetting conditions.