Natural gas Natural gas Natural gas is a naturally occurring hydrocarbon gas mixture consisting primarily of methane, but commonly including varying amounts of other higher alkanes, and sometimes a small percentage of carbon dioxide, nitrogen, hydrogen sulfide, or helium. It is formed when layers of decomposing plant and animal matter are exposed to intense heat and pressure under the surface of the Earth over millions of years. The energy that the plants originally obtained from the sun is stored in the form of chemical bonds in the gas. Natural gas is a fossil fuel used as a source of energy for heating,
Natural gas reserves in Iran with India and China the main markets for Iran’s gas exports. A recent report (December 11, 2011) from Iran's Petroleum Minister indicates that a large natural gas reserve was discovered inside Iran's side of the Caspian Sea. These reserves are estimated at 50 trillion cubic feet (1.42 trillion cubic meter). Natural gas reserves in Iran According to the Iran Petroleum Ministry, the proved natural gas reserves of Iran are about or about 17.8% of world's total reserves, of which 33% are as associated gas and 67% is in non associated gas fields. It has the world's second largest reserves after