AGOSTINO, PATRICK N., VICTOR T. JONES, III, and RUFUS LeBLANC, JR.
Exploration Technologies, Inc., Houston, TX

Abstract: Assessment and Remediation of Hydrocarbon Contamination in a Latin American Petroleum Facility

During the paving of a residential street in an area adjacent to a very large petroleum complex in Latin America, gasoline contamination was detected Within three feet of the surface. A geochemical soil gas survey established the horizontal extent of the contamination. To locate monitor wells and recovery systems, concentrations Of C₁-C₅+ soil gases were mapped and integrated with the local subsurface geology to identify pathways defined by high concentrations of light gases and contaminants. Based on the soil gas results, 104 monitor wells were installed; 82 had significant concentrations of contaminants, With 63 having up to 2 ft of liquid hydrocarbons on the ground water. Interceptor/recovery trenches, totaling 1600 ft in length and located on the basis of the soil gas survey (over 5000 soil gas samples were collected), soil analyses and ground water analyses, recovered over 1300 barrels of hydrocarbon products in less than one year.

Numerous contaminated areas were discovered, containing approximately 13 different products (gasolines, diesel, oils, crudes) that leaked into the subsurface over a 60 year period With the product reservoirs and migration pathways controlled by Recent environments of deposition. Contaminant reservoirs are vadose zone clayey silts and fine sands 4-10 feet deep, and migration is along either old braided stream floodplain channels or old alluvial fan channels entering the floodplain. Man-made utilities trenches also modify the migration routes of the contaminants.

AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas