Variability in Spatially and Temporally Resolved Emissions and Hydrocarbon Source Fingerprints for Oil and Gas Sources in Shale Gas Production Regions

A gridded inventory for emissions of methane, ethane, propane and butanes, from oil and gas sources in the Barnett Shale production region, has been developed. This inventory extends previous spatially resolved inventories of emissions by characterizing the overall variability in emission magnitudes, and the composition of emissions, at an hourly time resolution. The inventory is divided into continuous and intermittent emission sources. Sources are defined as continuous if hourly averaged emissions are greater than zero in every hour, otherwise they are classified as intermittent. In the Barnett Shale, intermittent sources accounted for 13-30% of the mean emissions for methane and 10-32% for ethane, leading to spatial and temporal variability in the location of hourly emissions. The combined variability due to intermittent sources and variability in emission factors can lead to wide confidence intervals in the magnitude and composition of time and location specific emission inventories, therefore, includ...