Abstract

As oil-field areas are being taken out of production and sold, there is increasing sensitivity to the environmental issues associated with these areas. The sensitivity is related primarily to liability for environmentally degraded (“contaminated”) areas and costs to remediate degraded soil, soil gas and/or groundwater. Sources of oil field degradation include oil wells, well cellars, sumps, pits and dumps, “ratholes”, reservoirs, above-ground storage tanks, pipelines, piping, headers and pump stations, gas separators, underground storage tanks, transformers, barrels, and ground surface. A variety of compounds that are encountered in these source areas are considered hazardous wastes or designated waste according to State or Federal regulatory guidelines. These compounds include methane gas, crude oil, refined petroleum products (gasoline, jet fuel, diesel fuel, etc. - primarily around pipelines, above-ground and underground storage tanks, and pumping equipment), aromatic (such as benzene, toluene, xylenes and ethylbenzene), and/or aliphatic hydrocarbon constituents of petroleum hydrocarbons; drilling muds (due to their heavy metal content; primarily in sumps and around wells), PCBs (in transformers and oil used for dust control), chlorinated volatile organic compounds (VOCs) (such as trichloroethylene (TCE) and other solvents in equipment maintenance areas), trash, herbicides and pesticides, and phenols. It is becoming increasingly important for buyers (and sellers) to investigate the extent of degradation before a property transfer involving an oil-field area is completed. Techniques that can be used include historical site usage review, geophysics, soil gas, cone penetrometer, drilling, trenching, soil sampling, monitoring well, piezometer, and/or well point installation, water sampling, and laboratory analysis of collected samples. Following site investigation, soil and groundwater remediation (If warranted) can include one or more of 16 alternatives such as landfarming, bioremediation, fixation, incineration, and disposal at landfill facilities. In California, remediation costs typically range from $50/cubic yard to $450/cubic yard (approximate all-inclusive costs).