ENVRIONMENTAL CONTAMINANT RELEASES FROM E&P OPERATIONS IN OKLAHOMA: TYPE, VOLUME, CAUSES AND PREVENTION

Rationale management and decision making regarding environmental management requires information. Although most oil and gas regulatory bodies have rules that specifically prohibit pollution, little is known about the specific origins, causes and magnitudes of pollution incidents that result from onshore exploration and production activities. This paper presents an analysis of over 18,000 fluid release incidents documented by the Oklahoma Corporation Commission (OCC) for the ten-year period from 1993 to 2003. Of these, nearly 17,000 were recent releases, and nearly 13,000 of these releases could be traced to exploration and production (E&P) operations within a specific section-township-range locations within Oklahoma. Fluid releases from E&P operations resulted from both preventable and non-preventable causes. The primary origins of oil and saltwater releases were from flowlines lines, tanks, wellheads, surface equipment and pits. Important causes of fluid releases, in order of decreasing number, were: overflows (tank, pit and dike), leaks (lines), intentional dumping or other illegal activity, storms, fires or explosions, accidents (including the actions of livestock) and corrosion. On average, over 58,000 bbls of oil and over 146,000 bbls of saltwater were released annually in Oklahoma between 1993 and 2003. Approximately 34% of all recent oil or saltwater releases resulted in reported injury to environmental receptors (surface water, crops or livestock, soil, fish or wildlife. For this period, 41% of all E&P complaints to the OCC involved the release of oil or saltwater and 54% of all E&P complaints to the OCC involved the release of some type of fluid. On an annual basis, complaints involving the release of fluids decreased from a high of 65.8% in 1993 to 46.1% in 2002. Releases specifically identified as involving oil or saltwater comprised 76.1% of all fluid releases. Quantified releases of oil had a median volume of 10 BBLs while quantified releases of saltwater had a median volume of 40 BBLs. For those releases in which the volume of both oil and saltwater were quantified, the volume of saltwater spilled was approximately 76% of the total volume of oil and saltwater released.