Kharaka, Yousif K.¹, William N. Herkelrath¹, Frances D. Hostettler¹ 
(1) U. S. Geological Survey, Menlo Park, CA

ABSTRACT: Impacts of Petroleum Production on Ground and Surface Waters: Results from OSPER “A” Site, Osage County, OK

We are involved in a multidisciplinary investigation to study the transport, fate, natural attenuation and impacts of released petroleum compounds and inorganic salts in produced water at the Osage-Skiatook Petroleum Environmental Research (OSPER) “A” and “B” sites in Oklahoma. At the OSPER “A” site, about 1.5 hectare of land has been impacted by oil operations that started in 1913 and were largely terminated by 1937. Impacts include salt scarring, tree kills, soil salinization and brine and petroleum contamination due to the leakage of produced water and associated hydrocarbons from brine pits and accidental releases from pipes and tank batteries. Groundwater impacts are being investigated by repeated sampling of 35 wells (1-36 m deep) completed with slotted PVC tubing. 
Results indicate a 3-D plume of high salinity water (5,000-30,000 mg/L TDS) with chemical and isotopic characteristics similar to those of the source produced water. The plume intersects Skiatook Lake, which provides drinking water to the local communities and is a recreational fishery, but the plume's depth and horizontal boundaries are not currently defined. One well penetrates a deeper aquifer with lower salinity (~2,000 mg/L TDS), but high Fe, Mn and dissolved organics, and all wells deeper than 2 m at the site encounter the plume. A ‘background’ well, located 0.6 km from the site has freshwater (450 mg/L TDS) and other characteristics of local groundwater, but also has high dissolved organics, including BTEX. Results show that large amounts of salts and organics remain in the local rocks and groundwater after more than 65 years of natural attenuation.

AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.