PREDICTING OIL INFILTRATION AND REDISTRIBUTION IN UNSATURATED SOILS

The infiltration and redistribution of two viscous hydrocarbon oils, with viscosities 4.7 and 77 times greater than water, were observed in columns of moist silt loam and loamy sand soils. The time required for water and oil to infiltrate the two soils and the final volumetric liquid contents after 8 h were measured. These observations are compared to the results predicted by a simple multiphase flow code based on scaling oil flow to unsaturated soil-water flow by using classical capillary theory and relative viscosities. A new function for describing the oil permeability was derived and, when used in the code, produced oil content distributions with depth that agreed reasonably well with those observed. The actual oil infiltration time was generally less than predicted, however. The flow of the two organic liquids into moist soils was found to be predictable, based only on classical soil-water relations and the organic liquids' physical properties, under the imposed experimental conditions.