Analysis of Soil Remediation Requirements of Abandoned Centralized and Commercial Drilling-Fluid Disposal Sites

Alan R. Dutton, principal investigator; Rebecca C. Smyth; assisted by Liying Xu and Susan Palachek

Drilling fluids from oil and gas exploration and production activities are sometimes contaminated with saltwater, crude oil, or drilling additives and are disposed of instead of recycled. A small percentage of spent drilling fluid is sent to centralized or commercial sites. Although current practices limit soil contamination at permitted offsite disposal locations, many older centralized commercial sites used for disposal of spent drilling fluid were abandoned without proper closure, leaving some uncertainty as to the extent and character of contaminants. Costs for assessment and remediation of abandoned sites are borne by states when responsible parties are not located or are insolvent. This new study for the U.S. Department of Energy will provide a synthesis of the data generated and lessons learned from assessment and remediation activities at abandoned oil-field waste-disposal sites in Louisiana, New Mexico, Oklahoma, and Texas. Better documentation and understanding of the relationships among soil contamination, waste constituents, drilling fluids, and constituents of concern will provide a basis for application of risk-based models to oil and gas waste and will make State regulation and State-funded cleanup of these abandoned sites more cost effective.