OK, here's another one of these which shows production going through the roof. This one is not as "old" as the Barnett Shale, but it's still been around long-enough to give you an idea that, yes, these shales can produce a ton of gas.
The Fayetteville Shale in Arkansas.
Here is 2004 production from the Fayetteville shale:
LINK (PDF)
^
On the last page, it says that
100,627 million cubic feet of gas was produced from the Fayetteville Shale in 2004. Notice also that it's only about 1-1/4 pages of well listings.
Jump forward just 3 years . . .
2007 Fayetteville Shale production:
LINK (PDF)
^
On the last page, it says that
89,167,902 million cubic feet of gas have been produced. Not all of them say they are from the "Fayetteville" target, but most of them are. The page I got them from
here is entitled "Fayetteville Shale Production Information," so maybe these other areas are sub-sections of the Fayetteville shale. At any rate, instead of just 1-1/4 pages of wells, it's got
109 pages of wells! And that production is almost a 900-fold increase!