Oil Field Hydrogen Sulfide in Texas:  Emission Estimates and Fate

Hydrogen sulfide is released into the atmosphere during oil recovery operations. However, little is quantitatively known concerning the total sulfur flux due to these fugitive emis sions. A mobile laboratory, equipped to measure atmospheric gases and meteorological parameters, was used to collect quantitative data in the vicinity of various oil field operations. Fugitive emissions of H2S and soil sulfate levels were studied. Concentrations of atmospheric sulfur gases (SO2, H2S, mercaptans) were measured in the oil-producing regions of several west Texas counties. Hydrogen sulfide was by far the dominant reduced sulfur gas in all locations. Except in the vicinity of refining/processing plants, mercaptan levels were below 200 pptv. Sulfur dioxide levels were also very low, typically below 200 pptv. In all locations, a strong diurnal pattern of the ambient H2S concentration was observed. Specific sources, the flux, and the fate of the H2S emitted in oil field operations was studied. Crude oil storage tanks were found to be the major sources of sulfur gas emissions. Soil sulfate levels downwind from oil storage tanks were 20−200 times higher than that in control regions of similar geology where no oil is produced. Even within an oil-producing area, soil sulfate levels immediately downwind from storage tank vents exceeded the corresponding levels of sulfate in soil located upwind by a factor of ≥100.