Table 1.
Data used to calculate the average δ13CCH4 in shale gases produced in the USA since 2008.
| Shale formation | Total dry shale gas production from 2008 to mid-2019 (bcm) | Portion (%) of total dry shale gas production from 2008 to mid-2019 | Average δ13CCH4 in produced gas (‰) | N of gas samples with δ13CCH4 |
|---|---|---|---|---|
| Marcellus | 1170 | 28 | −32.0 | 98 |
| Haynesville | 520 | 13 | −39.5 | 17 |
| Barnett | 460 | 11 | −42.7 | 450 |
| Permian basin (Wolfcamp, Avalon and others) | 360 | 9 | −49.5 | 13 |
| Rest of US shales | 236 | 6 | na | na |
| Eagle Ford | 319 | 8 | −42.9 | 50 |
| Utica | 245 | 6 | −31.8 | 4 |
| Fayetteville | 240 | 6 | −38.2 | 101 |
| Woodford (Anadarko and Arkoma basins) | 210 | 5 | −49.1 | 54 |
| Mississippian (Anadarko basin) | 137 | 3 | −50.3 | 7 |
| Niobrara-Codell (Denver basin) | 133 | 3 | −47.6 | 190 |
| Bakken | 85 | 2 | −47.3 | 19 |
| Total | 4114 | 100 | 1003 | |
| Total with gas data | 3879 | 94 | ||
| Production volume-weighted | −39.6 |