In the Reference case, total domestic natural gas
production grows from 20.6 trillion cubic feet in 2008
to 23.3 trillion cubic feet in 2035. With technology
improvements and rising natural gas prices, natural
gas production from shale formations grows to 6 trillion
cubic feet in 2035, more than offsetting declines
in other production. In 2035, shale gas provides 24
percent of the natural gas consumed in the United
States, up from 6 percent in 2008 (Figure 3).
And here are Rapier's comments from R Squared