LNAPL Apparent vs. Actual Thickness

3 APPARENT VS. ACTUAL NAPL THICKNESS 6.3.1 LNAPL Apparent vs. Actual Thickness 

One of the more difficult aspects in dealing with the subsurface presence of hydrocarbons, as a practical matter, is that NAPL accumulations in monitoring wells do not directly correspond to the actual thickness in the formation. The thickness of LNAPL product as measured in a monitoring well is an apparent thickness that is not reflective of the actual formation thickness. This relationship can be demon- 

FIGURE 6.3 Sandbox model showing LNAPL overlying capillary fringe, and apparent vs. actual LNAPL thickness. Saturated conditions (water table) are represented by the straight horizontal line. 

A three-phase zone containing water, LNAPL and air  

FIGURE 6.4 Conceptual representation of distribution of air, LNAPL, and water in a porous media. (After Farr et al., 1990.) 

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