Print this pageApplication of Environmental Assessment to Remediation of
Abandoned Oil 
Field
Sites
DUTTON, ALAN R., JEFFREY G. PAINE, and JOHN J. TINTERA
Hydrogeologic mapping and environmental geophysics can track contamination
sources, map subsurface contamination, and obtain data for cleanup of abandoned
oil field sites while minimizing the cost and risk involved in more intrusive
environmental drilling. For example, investigation into a complaint about a
vegetation kill next to an abandoned oil field site in East Texas turned up a
subsurface plume of sulfuric acid, leaching from spoil most likely taken from a
sour-gas processing plant for driveway material. Plume migration appeared
downslope in a seasonally saturated soil zone overlying a regional aquifer
system. A ground-conductivity (EM) survey conducted at multiple coil spacings
showed a shallow plume of high conductivity extending no farther than the
stressed vegetation. Modeling results predicted the depth of the conductive
plume and also matched expected subsurface geologic contacts. A minimum of
intrusive auger cores sufficed to prove that most of the sulfuric acid was
limited to the uppermost 4 ft of ground, with a gradation to background at a
depth of 10 ft, with little potential for downward migration. The total mass of
acid to be neutralized as part of site remediation was estimated from an
integration of EM and laboratory data
.