The Energy Information Agency (EIA) has released a report estimating the volumes of gas and oil recoverable from shale plays in the 48 contiguous United States: about 750 trillion cubic feet of gas, and 24 billion barrels of oil.
The agency makes note that its figures represent technically recoverable resources, and make no judgment on the financial viability of the exercise.
The EIA also notes that there are many factors which make estimating the size of the plays uncertain, including the list below:
- “Because most shale gas and shale oil wells are only a few years old, their long-term productivity is untested. Consequently, the long-term production profiles of shale wells and their estimated ultimate recovery of oil and natural gas are uncertain.
- In emerging shale plays, production has been confined largely to those areas known as “sweet spots” that have the highest known production rates for the play. If the production rates for the sweet spots are used to infer the productive potential of entire plays, their productive potential probably will be overstated. The INTEK shale report mitigates this problem by differentiating the productivity of a play’s sweet spot from the productivity for rest of that play.8
- Many shale plays are so large (e.g., the Marcellus shale) that only portions have been extensively production tested.
- Technical advancements could lead to more productive and less costly well drilling and completion.
- Currently untested shale plays, such as thin-seam plays or untested portions of existing plays, could prove to be highly productive.”
Read the full report here: http://www.eia.gov/analysis/studies/usshalegas/