--> Laboratory and Field Investigation of Relationship Between Actual and Apparent Product Thickness in Sands, by Duane R. Hampton; #91024 (1989)
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Laboratory and Field Investigation of Relationship Between Actual and Previous HitApparentNext Hit Product Thickness in Sands

Duane R. Hampton

Many people assume that Previous HitapparentNext Hit petroleum thicknesses measured in monitoring wells can be used to determine product volume in the ground. To this end, several published equations relate the Previous HitapparentNext Hit thickness to the actual thickness of the layer of mobile product in a contaminated aquifer. Our experiment evaluated these equations.

A large plexiglass tank filled with different sands, water, and dyed kerosene was studied photographically. The tank measured 4 ft tall, 4 ft wide, and 1 ft thick. Three well screens of differing diameters (2, 4, and 6 in.), which have been cut in half lengthwise, were attached to one side. The tank was filled with two different medium sands, a well-graded local sand and a screened silica sand. Water levels in the sands were controlled by adjusting the water levels in tanks at each end. The water levels were usually held constant during the experiments, but were lowered and raised to simulate a water table aquifer. Measured volumes of dyed kerosene were added, and actual Previous HitapparentNext Hit product thicknesses were recorded photographically periodically.

Several conclusions have been reached. Previous HitApparentNext Hit product thickness greatly exceeded the actual thickness. Attempts to relate these quantities by subtracting the capillary fringe thickness as suggested in 1984 by Hall, Blake, and Champlin or by dividing by a constant factor (usually around four) as suggested by CONCAWE were unsuccessful. We have not yet found any simple relationship between real and Previous HitapparentTop thicknesses. Hence, other methods of estimating actual product thickness should be pursued. Thicknesses in three different diameter monitoring wells varied greatly, but eventually reached equilibrium. This may not occur in the field where wells are farther apart.

AAPG Search and Discovery Article #91024©1989 AAPG Pacific Section, May 10-12, 1989, Palm Springs, California.