Shale gas - natural gas, commonly referred to as shale gas, obtained from shale rocks, characterized by a high content of organic matter and low values of porosity and permeability. Shale gas is found trapped in small spaces between rock layers. The volume of every space is several times smaller than with conventional resources. Shale gas is not different from natural gas - it contains methane (75 - 95%) and nitrogen as well as ethane, propane, helium, oxygen and carbon monoxide. It is odourless.