Characteristics and influence factors for oil displacement efficiency determination in low-permeability and complex reservoir simulation

Abstract

A review of methods to estimate residual NAPL saturation values has been conducted. Traditional laboratory methods use high capillary pressures in saturating the porous media with NAPL to an artificially high starting point. This often results in over-estimation of residual NAPL saturation, especially for environmental applications in surficial shallow aquifers. Comparison of literature values with 270 LNAPL measurements from 10 field sites confirms that many of the literature residual NAPL saturation values are not consistent with field observations. It is concluded that laboratory methods for estimation of residual NAPL saturation values should be developed to include water saturation and capillary pressures that are representative of NAPL releases to shallow subsurface environments.