The early 2011 report by U.S. Energy Information Administration (EIA) shows that the addition of shale gas resources in existing plays which can be produced at prices under $7 per thousand cubic feet results in higher shale gas production overall. Technically recoverable unproved shale gas resources are now estimated at 827 trillion cubic feet.
The annual average natural gas wellhead price will remain under $5 per thousand cubic feet through 2022, but it will increase thereafter because significantly more shale wells must be drilled to meet growth in natural gas demand and offset declines in natural gas production from other sources. As the shale gas resource base is developed, production may gradually shift to resources that are somewhat less productive and more expensive to produce. Natural gas wellhead prices (in 2009 dollars) will reach $6.53 per thousand cubic feet in 2035.
As a result of updated shale gas resources in existing plays (key additions were in the Marcellus, Haynesville, and Eagle Ford plays) and an assumption of increased well productivity for the newer plays, shale gas production in 2035 is expected to be double of what was predicted last year.
There is considerable uncertainty about the amounts of recoverable shale gas in both developed and undeveloped areas. Well characteristics and productivity vary widely not only across different plays but within individual plays.
Many shale formations, such as the Marcellus Shale, are so large that only a small portion of the entire formation has been intensively production-tested. Environmental considerations, particularly in the area of water usage, lend additional uncertainty.