Environmental effects of produced waters at oilfield production sites in the Big Sinking Creek and Schumaker Ridge areas, Lee County, Kentucky

Abstract

During July of 1995 and June of 1996, thirteen oilfield production sites in the Big Sinking Creek and Schumaker Ridge areas of northern Lee County in eastern Kentucky were visited to determine if produced waters and produced water solids had impacted sites in this area. Salt-scarred areas at oilfield production sites in this area were found to be relatively restricted in size, not very deeply eroded compared to sites in the midwest and southwest, and to have revegetated fairly quickly, probably because of the high rainfall and rapid flushing of salts from the root zone of plants. Saline groundwater still remains in the shallow subsurface beneath small barren areas at some sites. Areas of barren or sparse vegetation at some sites were found to be underlain by oil-saturated soil at shallow depths suggesting that the oil inhibits plant growth. Seepage of brine at one site has raised stream conductivities about 35-45 percent higher than values just upstream. Five sites have slightly anomalous concentrations of copper, lead, and zinc in soils containing tank sludge. Two samples from one site have high levels of radium (1770-3390 pCi/g), copper (165-195 ppm), and lead (200-245 ppm). These two samples have high concentrations of barium and strontium and low concentrations of zirconium suggesting that they are composed mostly of solids from tank sludge and that barite is present in high concentrations. The lead levels in these two samples are below action levels used for Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and Resource Conservation and Recovery Act (RCRA) sites (400 ppm). Radiometric surveys and radiochemical analyses determined that 9 of 13 sites have high radioactivity and radium in equipment, soils, and wetland sediments. Moderate levels occur at 2 sites and low levels occur at 2 sites. Radium-rich tank sludge, soils, and sediments are widespread at one site at the northern end of Lake Zachariah. Sites with high radioactivity in equipment or high radium activity in soils would be Naturally Occurring Radioactive Material (NORM)-contaminant sites under the least conservative state regulations proposed or in place. The State of Kentucky does not presently have NORM regulations. Dispersion of radium is occurring in two ways: 1) by the movement of radium-bearing solids (mostly barite), and 2) movement of dissolved radium in water. Iron oxyhydroxide precipitates are forming in the seep zone in a small wetland downslope from a tank battery at one site. These precipitates are radioactive and the iron oxyhydroxides are probably adsorbing dissolved radium from the ground water. Elsewhere at this same site, radium-bearing barite is accumulating at the edge of and probably within the wetland at the toe of the slope below a large area of radiumenriched soils. Figure IB-Location map showing 13 oilfield production sites visited during this study in the Big Sinking Creek and Schumaker Ridge areas of northern Lee County. X-study sites (in the text the sites are designated LC95-1 to LC95-13). ...

Sulfate-Reducing Bacteria Release Barium and Radium from Naturally Occurring Radioactive Material in Oil-Field Barite

“…LC is a sample of anaerobic sediment, collected from a sediment depth of 0.25-0.5 m in an abandoned brine pond with wetland overgrowth, and is composed of barite (6.7 wt%) and quartz (Otton et al 1997a). LC had the greatest initial extractable sul de content (35% of the total S in the sample), suggesting that sulfate reduction may be an important microbial process at this site.…”

“…"LC" (LC95-2A, Otton et al 1997a) was collected at an oil-eld production site in Lee County, Kentucky. LC is a sample of anaerobic sediment, collected from a sediment depth of 0.25-0.5 m in an abandoned brine pond with wetland overgrowth, and is composed of barite (6.7 wt%) and quartz (Otton et al 1997a).…”