Analysis of Oil and Gas Ethane and Methane Emissions in the Southcentral and Eastern United States Using Four Seasons of Continuous Aircraft Ethane Measurements

Barkley, Z.; Davis, Kenneth J.; Feng, Sha; Cui, Yu Yan; Fried, Alan; Weibring, P.; Richter, Dirk; Walega, J.; Miller, Scot M.; Eckl, Maximilian; Roiger, A.; Fiehn, Alina; Kostinek, Julian

doi:10.1029/2020jd034194

Cited by 23 publications

(27 citation statements)

References 67 publications

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“…6 This development utilizes new advances in horizontal drilling and high-pressure, high-volume hydraulic fracturing to extract oil and gas from deep, low-permeability rock such as shale and now represents a significant but poorly quantified source to the atmosphere. 7,8 Anthropogenic releases of previously deeply buried gas derived from high-temperature rock processes (so-called thermogenic natural gas) occur in addition to the low natural rates of emission of thermogenic gas in hydrocarbon-rich basins worldwide. 9 Methane increasingly plays a key role in providing energy for the United States in the form of natural gas, and it has been touted as a bridge fuel to more renewable energy sources.…”

Section: ■ Introductionmentioning

confidence: 99%

Measurements of Atmospheric Methane Emissions from Stray Gas Migration: A Case Study from the Marcellus Shale

Dennis

Richardson

Miles

et al. 2022

ACS Earth Space Chem.

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Understanding emissions of methane from legacy and ongoing shale gas development requires both regional studies that assess the frequency of emissions and case studies that assess causation. We present the first direct measurements of emissions in a case study of a putatively leaking gas well in the largest shale gas play in the United States. We quantify atmospheric methane emissions in farmland >2 km from the nearest shale gas well cited for casing and cementing issues. We find that emissions are highly heterogeneous as they travel long distances in the subsurface. Emissions were measured near observed patches of dead vegetation and methane bubbling from a stream. An eddy covariance flux tower, chamber flux measurements, and a survey of enhancements of the near-surface methane mole fraction were used to quantify emissions and evaluate the spatial and temporal variability. We combined eddy covariance measurements with the survey of the methane mole fraction to estimate total emissions over the study area (2,800 m2). Estimated at ∼6 kg CH4 day–1, emissions were spatially heterogeneous but showed no temporal trends over 6 months. The isotopic signature of the atmospheric CH4 source (δ13CH4) was equal to −29‰, consistent with methane of thermogenic origin and similar to the isotopic signature of the gas reported from the nearest shale gas well. While the magnitude of emissions from the potential leak is modest compared to large emitters identified among shale gas production sites, it is large compared to estimates of emissions from single abandoned wells. Since other areas of emissions have been identified close to this putatively leaking well, our estimate of emissions likely represents only a portion of total emissions from this event. More comprehensive quantification will require more extensive spatial and temporal sampling of the locations of gas migration to the surface as well as an investigation into the mechanisms of subsurface gas migration. This work highlights an example of atmospheric methane emissions from potential stray gas migration at a location far from a well pad, and further research should explore the frequency and mechanisms behind these types of events to inform careful and strategic natural gas development.

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Section: ■ Introductionmentioning

confidence: 99%

Measurements of Atmospheric Methane Emissions from Stray Gas Migration: A Case Study from the Marcellus Shale

Dennis

Richardson

Miles

et al. 2022

ACS Earth Space Chem.

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“…The US is one of the largest anthropogenic emitters of methane, behind only China and India (Saunois et al 2020). Numerous recent studies indicate that US methane emissions are 48% -76% higher than estimated by the EPA Inventory of US Greenhouse Gas Emissions and Sinks (GHGI) (Alvarez et al 2018;Barkley et al 2019Barkley et al , 2021Caulton et al 2019;Robertson et al 2020;Zavala-Araiza et al 2015). One reason for this discrepancy is that methane emissions are challenging to quantify.…”

Section: Introductionmentioning

confidence: 99%

Meteorology, not emissions, helps explain an upward trend in atmospheric methane across the US

Feng

Tavakkoli

Jordaan

et al. 2022

Preprint

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US natural gas production increased by ˜43% between 2005 and 2015, but there is disagreement in the scientific literature on whether this growth led to increased methane emissions. In this study, we evaluate the possible contributions of emissions versus meteorology to an upward trend in US atmospheric methane observations during 2007-2015. We find that interannual variability (IAV) in meteorology yields an apparent upward trend in atmospheric methane across much of the US. We further find that IAV in atmospheric methane at several observation sites is correlated with IAV in local wind speed. Overall, our results show that US trends in atmospheric methane largely reflect variability in meteorology, and are unlikely to be a direct reflection of trends in emissions. The results of this study therefore lend support for the conclusion that there was little upward trend in US methane emissions during this time.

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“…In urban environments, most of the anthropogenic CO 2 sources are from fossil fuel-related combustion, such as electricity generation and vehicle combustion, and point sources such as large industrial facilities . CH 4 is the second most important greenhouse gas which contributes to 17% of the total anthropogenic direct radiative forcing and has a global warming potential of 21 times that of CO 2 over a 100-year period . Thus, CH 4 emissions also play a large role in atmospheric warming and act as an important, potential feedback for climate change.…”

Section: Introductionmentioning

confidence: 99%

“…8 CH 4 is the second most important greenhouse gas which contributes to 17% of the total anthropogenic direct radiative forcing and has a global warming potential of 21 times that of CO 2 over a 100-year period. 9 Thus, CH 4 emissions also play a large role in atmospheric warming and act as an important, potential feedback for climate change. CO is an air pollutant that is mainly produced during the incomplete combustion of fossil fuels that contain carbon and is also considered an indirect global warming potential gas.…”

Section: Introductionmentioning

confidence: 99%

Unexpected Urban Methane Hotspots Captured from Aircraft Observations

Jeong

Park

Kim

et al. 2022

ACS Earth Space Chem.

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Cities are key contributors to climate change as they are major sources of greenhouse gases and air pollutants. We use aircraft measurements of carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO) made during 2 observation days to monitor the urban atmosphere of Seoul, a megacity with large anthropogenic emissions. We estimate that CO2, CH4, and CO concentrations of anthropogenic emissions extracted from background concentrations (i.e., urban enhancements; ΔCO2, ΔCH4, and ΔCO) are higher on average by 50.2, 68.6, and 26.9%, respectively, in the areas within Seoul (17.1 ppm, 85.8 ppb, and 295.3 ppb, respectively) compared to areas in the outer parts of the boundaries of the city (11.4 ppm, 50.9 ppb, and 232.6 ppb, respectively). We also compare the emission ratios of ΔCO:ΔCO2, ΔCH4:ΔCO2, and ΔCH4:ΔCO to detect hotspots and characterize emission sources using the urban enhancements. We find that the urban emission ratios of ΔCH4:ΔCO2 show the highest slopes in the West and East sectors of Seoul (10.33 ± 4.55 and 14.50 ± 1.91, respectively). Moreover, in addition to discovering urban CH4 hotspots around Seoul, we unveil unexpected CH4 emissions and leakage during the supply of LNG from a large commercial multicomplex building. Our study suggests the effectiveness of aircraft measurements and ratio analyses to understand anthropogenic emissions of urban areas which support and improve the efforts of urban greenhouse gas and air pollutant monitoring.

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Analysis of Oil and Gas Ethane and Methane Emissions in the Southcentral and Eastern United States Using Four Seasons of Continuous Aircraft Ethane Measurements

Cited by 23 publications

References 67 publications

Measurements of Atmospheric Methane Emissions from Stray Gas Migration: A Case Study from the Marcellus Shale

Measurements of Atmospheric Methane Emissions from Stray Gas Migration: A Case Study from the Marcellus Shale

Meteorology, not emissions, helps explain an upward trend in atmospheric methane across the US

Unexpected Urban Methane Hotspots Captured from Aircraft Observations

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