Residual Saturation:What is it? How is it Measured? How Should We Use it?

摘要

A review of methods to estimate residual NAPL saturation values has been conducted. Traditionalrnlaboratory methods use high capillary pressures in saturating the porous media with NAPL to an artificiallyrnhigh starting point. This often results in over-estimation of residual NAPL saturation, especially forrnenvironmental applications in surficial shallow aquifers. Comparison of literature values with 270 LNAPLrnmeasurements from 10 field sites confirms that many of the literature residual NAPL saturation values arernnot consistent with field observations. It is concluded that laboratory methods for estimation of residualrnNAPL saturation values should be developed to include water saturation and capillary pressures that arernrepresentative of NAPL releases to shallow subsurface environments.