Determining the nature and sources of subsurface petroleum is a frequent need for refinery management. Hellenic Petroleum (the Hellenic Aspropyrgos Refinery), Greece’s largest refinery, was faced with identifying the makeup of a major subsurface pool of petroleum discovered beneath its facility just outside of Athens. Finding and mitigating the source(s) of this free product was necessary before control and remediation strategies for the fugitive petroleum could be developed. Complicating the source identification challenge was the large number of possible on-site sources for the fugitive petroleum, including pipelines and nearly 100 bulk storage tanks. Hellenic was also concerned about the presence of petroleum that had been discovered in nearby Lake Koumoundourous, an area of significant archaeological interest and natural beauty.

After an investigation by the Greek Institute of Geology and Mineral Exploration, a contractor recovered large quantities of petroleum from the Hellenic site from 1993 to 1997. Although the estimated pumpable quantity was approximately 18,000 cubic meters and the recovered quantity was 44,600 cubic meters, the plume remained large. While conventional approaches to delineating the nature of subsurface oil at the site had met with only limited success, such reconnaissance studies suggested that the plume was fed by multiple sources.

Hellenic needed to pinpoint the sources of the petroleum releases, and they turned to Battelle for one of its specialties: environmental forensics. After groundwater and product samples were taken from a network of monitoring wells and from crude oil, distillation, and product streams, Battelle scientists subjected them to a battery of sophisticated chemical fingerprinting techniques. Using the unique chemical signatures found in the products as markers, Battelle consultants determined the different petroleum products present at different locations in the plume.

Integrating the petroleum composition data with historic tank and pipeline handling information, Battelle consultants then identified specific bulk storage tanks that were most likely contributing petroleum to the subsurface plume. Another important sidebar investigation determined that the petroleum product found in Lake Koumoundourous did not resemble any of those found in the refinery subsurface, suggesting that the source to the lake did not come from the Hellenic site.

As the Hellenic Petroleum project moves into site remediation, chemical fingerprinting methodologies will serve as exceptionally sensitive tools to support an array of remediation monitoring activities.

For more information, please contact Dr. Allen Uhler at (781) 952-5225, uhler@battelle.org.