Shale gas

Shale gas is natural gas that comes from shale, a kind of sedimentary rock. Most natural gas in the Earth is shale gas, but getting it out of the ground is difficult.

The issues with shale gas are rather similar to oil sands. In fact all types of oil and hydrocarbon gas in the ground were made during the far ancient past when the climate was much warmer than today.Hein, Fran. 2013. Geology of the Oil Sands (PDF). Association of Petroleum Engineers and Geoscientists of Alberta. 

 References 

Category:Sedimentary rocks
Category:Fossil fuels
Category:Hydrocarbons