| The objective of this research was to examine the influence of capillary forces on two-phase liquid flow in groundwater. This objective was accomplished by investigating interfacial tension, contact angle, capillary pressure, and relative permeability for systems representative of contaminated aquifers.;The interfacial tensions of six compounds, benzaldehyde, bromobenzene, n-dodecane, tetrachloroethylene, 1,1,2-trichloroethane, and o-xylene, were measured using the pendant drop method. These measurements show that the interfacial tensions for organic-water systems are significantly below that for an air-water system. Consequently, the capillary behavior of an air-water system is a poor indicator of the behavior of an organic compound-water system.;The contact angles for these six compounds were measured on five solid surfaces: Teflon, glass, steel, calcite, and albite. The measurements showed that the adhesion tension decreased with decreasing interfacial tension. This decrease stemmed from the dissolution of the organic compound in the aqueous phase, causing an increase in the interfacial tension between the aqueous phase and the hydrophilic solids, and a decrease between this phase and Teflon. These results form the base of a method for the prediction of the contact angle in organic liquid-water systems on low-energy surfaces.;Drainage and imbibition capillary pressure relationships were measured for four organic compound-water systems in an unconsolidated sand. These measurements showed that as the capillary force decreased, the displacement pressures for both processes decreased and the residual saturation of both liquid phases increased. Models for scaling the relationship agreed reasonably well with the observed data. This agreement allows for the prediction of capillary pressure curves for other organic liquid-water systems in a particular sand, once one set of measurements is obtained.;Drainage and imbibition relative permeabilities were measured at groundwater velocities for three organic compound-water systems in the same sand. As the capillary force decreased, the relative permeability to the wetting phase increased, whereas that to the nonwetting phase decreased. The relative permeability to the nonwetting phase was substantially smaller than anticipated. Also, the estimations of the relative permeability to the wetting phase became poorer as the capillary force decreased. Thus, current methods for estimating relative permeability may be inadequate. |
