Table 1 Data used to calculate the average δ13CCH4 in shale gases produced in the USA since 2008.

From: Using global isotopic data to constrain the role of shale gas production in recent increases in atmospheric methane

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

 
  1. Production data are from Energy Information Administration17. See Text S2 in Supplementary Information for specific details on Permian, Utica and Niobrara-Codell samples. na – not available.