TA [2] Continuous, regional methane emissions estimates in northern Pennsylvania gas fields using atmospheric inversions
- Pennsylvania State Univ., University Park, PA (United States)
Natural Gas (NG) production activities in the northeastern Marcellus shale have significantly increased in the last decade, possibly releasing large amounts of methane (CH4) into the atmosphere from the operations at the productions sites and during the processing and transmission steps of the natural gas chain. Based on an intensive aircraft survey, leakage rates from the NG production were quantified in May 2015 and found to be in the order of 0.5% of the total production, higher than reported by the Environmental Protection Agency (EPA) but below the usually observed leakage rates over the shale gases in the US. Thanks to the high production rates on average at each well, leakage rates normalized by production appeared to be low in the northeastern Marcellus shale. This result confirms that natural gas production using unconventional techniques in this region is emitting relatively less CH4 into the atmosphere than other shale reservoirs. The low emissions rate can be explained in part by the high productivity of wells drilled across the northeastern Marcellus region. We demonstrated here that atmospheric monitoring techniques can provide an independent quantification of NG leakage rates using aircraft measurements. The CH4 analyzers were successfully calibrated at four sites across the region, measuring continuously the atmospheric CH4 mixing ratios and isotopic 13Ch4. Our preliminary findings confirm the low leakage rates from tower data collected over September 2015 to November 2016 compared to the aircraft mass-balance estimates in may 2015. However, several episodes revealing large releases of natural gas over several weeks showed that temporal variations in the emissions of CH4 may increase the actual leakage rate over longer time periods.
- Research Organization:
- Pennsylvania State Univ., University Park, PA (United States); National Energy Technology Laboratory (NETL), Pittsburgh, PA, Morgantown, WV (United States)
- Sponsoring Organization:
- USDOE Office of Fossil Energy (FE), Oil & Natural Gas
- DOE Contract Number:
- FE0013590
- OSTI ID:
- 1417183
- Report Number(s):
- DOE-PSU-6986_final
- Country of Publication:
- United States
- Language:
- English
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