Quantification of natural gas and other hydrocarbons from production sites in northern West Virginia using tracer flux ratio methodology
Citation:
Daube, C., S. Herndon, J. Krechmer, D. Johnson, N. Clark, T. Footer, AND E. Thoma. Quantification of natural gas and other hydrocarbons from production sites in northern West Virginia using tracer flux ratio methodology. Atmospheric Environment: X. Elsevier B.V., Amsterdam, Netherlands, 19:na, (2023). https://doi.org/10.1016/j.aeaoa.2023.100220
Impact/Purpose:
Advancement in energy extraction technologies has driven unprecedented expansion of oil and natural gas (ONG) production in many regions of the U.S. Methane, ozone precursors, and hazardous air pollutants, such as benzene, are emitted as part of ongoing ONG production operations. A growing body of research indicates that fugitive leaks and equipment/process malfunctions are important ONG emissions categories that may not be properly reflected in emission inventories. These stochastic sources can produce significant impacts to near-source populations, regional air sheds, and greenhouse gas budgets. Environmentally sustainable development of ONG assets requires improved understanding and management of these sources. Development of cost-effective approaches to rapidly detect and control unnecessary emissions, along with a deeper understanding of overall emission levels and atmospheric effects are important research themes in this space. Under its next generation emissions measurement (NGEM) program, ORD is working to develop and use new measurement, modeling, and inventory approaches relevant to EPA partners, industry, and communities. This paper described a research study that used mobile NGEM approaches to characterize air pollutant emissions from 15 working ONG production sites in West Virginia that supported 66 working wells. This paper is a companion to two other research papers that used on site NGEM approaches to detect and measure emissions.
Description:
Tracer flux ratio (TFR) methodology performed at 15 active oil and natural gas production sites in Ohio County, West Virginia sought to quantify downwind emissions on several days in April 2018. In coordination with a production company, sites were randomly selected depending on wind forecasts and nearby road access. Methane (CH4), ethane (C2H6), and tracer gas compounds (acetylene and nitrous oxide) were measured via tunable infrared direct absorption spectroscopy. Ion signals attributed to benzene (C6H6) and other volatile gases (e.g., C7 – C9 aromatics) were measured via proton-transfer reaction time-of-flight mass spectrometry. Short-term whole facility emission rates for 12 sites are reported. Results from TFR were systematically higher than the sum of concurrent on-site full flow sampler measurements, though not all sources were assessed on-site in most cases (Footer et al., 2022 (in review), Johnson et al., 2022 (in review)). In downwind plumes, the mode of the C2H6:CH4 molar ratio distribution for all sites was 0.2, which agreed with spot sample analysis from the operator. Distribution of C6H6:CH4 ratios was skew but values between 1 and 5 pptv ppbv-1 were common. Additionally, the aromatic profile has been attributed to storage tank emissions. Average ratios of C7 – C9 to C6H6 were similar to other literature values reported for natural gas wells.
URLs/Downloads:
DOI: Quantification of natural gas and other hydrocarbons from production sites in northern West Virginia using tracer flux ratio methodology