Answer:
Saudi Arabia: In 1980, the ratio of global oil reserves to production, measured in years, was 29.66. In 2019, it increased to 49.9 years. This means that at the current (2019) level of production, global oil reserves will last another 50 years before being depleted.
Iran
With 155.6 thousand million barrels in 2018, Iran holds the second-biggest oil reserves in the Middle East. The country has 9% of the world’s total proved oil reserves. It is ranked fourth globally among the countries with the largest oil reserves, behind Venezuela, Saudi Arabia, and Canada.
Major oil fields in Iran include the Marun oil field, the Ahvaz field, the Gachsaran field, the Aghajari field, and the Esfandiar field. Located in the Khuzestan province of Iran, the Marun field is estimated to contain recoverable oil reserves of 22 billion barrels making it one of the world’s biggest onshore oil fields. It was brought on stream in 1966.
The onshore Ahvaz field in the Khuzestan region is considered to be among the three largest oil fields in the world in terms of production. Ahvaz, which is owned by National Iranian Oil Company (NIOC), and operated by National Iranian South Oil Company (NISOC), has been in production since 1954.
Iraq
Iraq takes third spot in the list of countries with the biggest oil reserves in the Middle East, with 147.2 thousand million barrels in 2018. The country produces nearly 90% of its crude oil from onshore oil fields in the southern part of the country.
The cities of Basra, Baghdad, and Ramadi hold much of the country’s reserves and, according to World Bank, Iran needs an annual investment of $1bn (£760m) to continue its current oil production rate.
The country operates the world’s third-largest producing field, Rumaila, which is estimated to have around 17 billion barrels of recoverable oil remaining.
Iraq also operates the Majnoon field, located in southern Iraq. This field is claimed to be among the richest oil fields in the world, with oil reserves of 23 to 25 billion barrels and proven reserves of 12.8 billion barrels of oil.
Kuwait
, despite being a small country, is a significant contributor to the world’s oil reserves, and the fourth biggest in terms of oil reserves in the Middle East. These stood at 101.5 thousand million barrels in 2018
The United Arab Emirates (UAE), which is among the world’s 10 largest oil producers, is the fifth largest country in terms of oil reserves at 97.8 thousand million barrels in 2018.