About 80% of the world's total proven natural gas reserves are in ten countries. While the Middle East holds the largest proved reserves by region, Russia is the largest reserve holder by country.
In 2016, global proved gas reserves increased slightly by 1.2 trillion cubic metres (tcm) or 0.6% to 186.6 tcm.
The proven reserves are enough to last 50 years at current production rate, according to BP Statistical Review of World Energy.
Russia: Russia holds about one fourth of the world's total proven gas reserves. It reserves stood at 47.8 trillion cubic metre (Tcm) as of January 2016.
A significant number of Russia's gas reserves are in Siberia.
Yamburg, Urengoy and Medvezh'ye are the 3 main natural gas fields in Siberia, contributing to nearly 45% of the country's reserves.
State-run Gazprom accounts for more than two-thirds of the country's natural gas production. Besides, it controls over 65% of proven gas reserves in the country.
Novatek, Lukoil and Rosneft are the other major producers of natural gas in Russia.
Iran: With a proven natural gas reserves of 34tcm, Iran holds the world' s 2nd biggest natural gas reserves.
However, international sanctions and delays have hit the development of most of the gas reserves in the country.
More than half of the reserves are located offshore, with South Pars being the Iran's largest gas field.
South Pars consists of more than a quarter of Iran's total proved natural gas reserves and accounts for 35% of the country's natural gas production.
Other major gas fields of the country include North Pars, Kish and Kangan.
The development and production of natural gas resources is managed by NIOC.
Qatar: Holding proven natural gas reserves of 24tcm, Qatar stands at 3rd spot in the list of the world's biggest natural gas reserves.
The country has about 13% of the world's total natural gas reserves. A significant part of the country's gas reserves are located in the giant offshore North Field.
Apart from being a major source of Qatar's natural gas production, North Field is the world's largest non-associated gas field.
USA: The US holds the world's 4rth largest natural gas reserves, with 10.4tcm of proven reserves.
Due to increased exploration and development activities in its shale formations, the country has significantly expanded its reserves since 1999.
The major shale formations that led to an increase in the US gas reserves include The Barnett play located in Texas and Montana, Haynesville play in the Texas-Louisiana Salt Basin, Marcellus Shale play in the Appalachian Basin, Fayetteville play, Woodford play in Oklahoma and Texas and the Eagle Ford play.
Saudi Arabia: Saudi Arabia holds the 5th largest natural gas reserves in the world. Its proven reserves stood at 8.4tcm as of January 2016.
The Ghawar onshore field and the offshore fields Safaniya and Zuluf, hold more than half of the country's proven gas reserves.
The Ghawar field accounts for more than a quarter of Saudi Arabia's gas reserves.
Other non-associated gas fields under development include Arabiyah and Hasbah gas fields.
The entire gas produced by the country is consumed domestically.
Saudi Aramco, a state-owned company, manages the gas production in the country.