Shale gas resources are potentially huge, but so far only the US that has taken advantage of this low permeability reservoir rock.
Shale gas has rejuvenated the natural gas industry in the US, starting in the 1980s and 1990s when engineers experimented with making deep shale gas production commercial in the Barnett Shale in Texas. By about 2005 output had reached 0.5 Tcf per year, and several other plays were being pursued in the lower 48 (e.g. Fayettville, Haynesville, Marcellus and Eagle Ford Shales).
