Gas reserves, like oil reserves, are categorized in three groups: proven reserves, probable reserves and possible reserves. The volume of the proven natural gas reserves has tripled over the last three decades. That is to say, the proven gas reserves from about 72 Trillion Cubic Meters (TCM) in 1970 has reached over 187 TCM at the beginning of 2016 and Iran with 34 TCM (18.2 percent of the total) of the world gas reserves ranks the first among the reservoir holders.

Among the operated gas reservoirs in Iran, two reservoirs namely Maroun Khami located in Southeast of Ahwaz and South Pars are of extreme importance. Especially, South Pars as the second and most important gas reservoir of Iran owns 50 percent of the country’s whole gas reserves and more than 8 percent of the world’s.

Top Ten Gas Reserve Holder Countries in the World in the beginning of 2016