Quantifying Activity Counts, Emission Profiles and Emission Factors for Natural Gas Production on a Component- to Site-Level Scale Using Detailed Emissions Inventory Data from the Barnett Shale

Abstract:

The use of horizontal drilling with hydraulic fracturing in the United States has led to the unforeseen development of hydrocarbon extraction from shale formations. This has led to scrutiny regarding air quality impacts of this development. Significant attention has focused on quantifying venting and fugitive emissions for greenhouse gases and VOCs. We generate emission factors using a 2011 emissions inventory data set from the Barnett Shale. Commissioned by the city of Fort Worth, the inventory contains component and equipment-based leakage rates from 388 unique sites including 1,138 wells. With component counts ranging from 188 compressors to over 600,000 connectors, our data set is more robust than previous data sets used for the development of emission factors. For the 2,126 leaks with concentrations measured by a toxic vapor analyzer to be greater than 500 ppmv or otherwise detected by infrared camera, we develop normalized activity counts and emissions profiles on a per-well and per-site basis. We classify these leaks, along with minor, default zero, and compressor engine emissions, into nine categories. From this we develop emission factors ranging from the component- to site-level scale and compare our results with existing emission factors (e.g, EPA, API, California Air Resources Board) and the current literature.