Sustainability 2011 , 3 2091
Table 4. Total cost per GJ, Net EUR and EROI for natural gas wells.
Year
Total Cost
$(U.S. 2002)
per GJ
Invested Energy per
GJ via 24 MJ/$(U.S.
2002) in MJ
Net Estimated
Ultimate Recovery
(1 e^9 GJ)
EROI
1996 $1.13 27 4.79 37
1997 $1.26 30 5.72 33
1998 $1.32 32 5.74 31
1999 $1.28 31 5.44 33
2000 $1.57 38 5.83 27
2001 $1.82 44 6.18 23
2002 $1.74 42 5.39 24
2003 $1.95 47 5.88 21
2004 $2.17 52 6.42 19
2005 $2.86 69 5.57 15
2006 $2.97 71 5.97 14
2007 $3.01 72 4.41 14
2008 $3.24 78 4.09 13
Figure 8. EROI using NEB estimates of ultimate recovery, with meters drilled.
The EROI curve in Figure 8 is slightly less volatile than the rolling average technique, but more
strikingly, the years 2007 and 2008 do not show the rebound in EROI that the rolling average method
displayed. Assuming the NEB estimates for EUR are correct, this result indicates that the rebound was
0
2
4
6
8
10
12
14
16
18
20
0
5
10
15
20
25
30
35
40
1992 1994 1996 1998 2000 2002 2004 2006 2008 2010
Distance
Drilled
(1e6
Meters)
Energy
Returned
on
Energy
Invested
Natural Gas Well EROI EROI via NEB Estimated Recovery
Gas Intent Meters Drilled