Table 2.
Data used to calculate the emission-weighted average δ13C of CH4 emitted from, mostly, shale gas production in selected plays and areas in the USA in 2015.
| Shale formation and basin/area | Gas production (m3/d) | Emitted gas (% of production) | CH4 emissions (tones/hr) | Average δ13C (‰) of emitted CH4 |
|---|---|---|---|---|
| Eagle Ford | 1.54E + 08 | 2.5 | 83 | −42.9 |
| Haynesville | 1.50E + 08 | 1 | 42 | −39.5 |
| Marcellus (N.E. PA) | 1.40E + 08 | 0.4 | 18 | −32.0 |
| Barnett | 1.20E + 08 | 1.5 | 46 | −42.7 |
| Fayetteville | 6.80E + 07 | 1.5 | 31 | −38.2 |
| Niobrara-Codell (Denver) | 3.80E + 07 | 2.1 | 18 | −47.6 |
| Bakken | 3.70E + 07 | 5.4 | 29 | −47.3 |
| Total | 7.07E + 08 | 267 | ||
| Volume-weighted average | 1.6 | |||
| Emission-weighted average | −41.8 |
Gas production, percentage of emitted gas, and CH4 emissions are from Peischl et al.19 and references therein. These results account for ~60% of total USA shale gas production in 2015.