1 – Ghawar Field - Saudi Arabia - 83 billion barrels
Located in Al-Ahsa Governorate, Saudi Arabia. Measuring 280 by 30 km (174 by 19 mi), it is by far the largest conventional oil field in the world. Ghawar is entirely owned and operated by Saudi Aramco, the state run Saudi oil company.
2- Burgan Field – Kuwait – 72 billion barrels
The onshore supergiant Burgan field is an oil field situated in the desert of southeastern Kuwait. Burgan field can also refer to the Greater Burgan—a group of three closely spaced fields, which includes Burgan field itself as well as the much smaller Magwa and Ahmadi fields. Greater Burgan is the world's largest sandstone oil field, and the second largest overall, after Ghawar.
3 – Mesopotamian Foredeep baisin – Kuwait – 72 billion
The Mesopotamia Foredeep is an integral part of the Zagros Fold – Thrust Belt. It is the
present day expression of the continental part of the major Zagros Foreland Basin, whereas
the Arabian Gulf Basin represents its marine counterpart.
4 – Tengiz field – Kazakhstan – 40 billion barrels
Tengiz field is an oil and gas field located in northwestern Kazakhstan's low-lying wetlands along the northeast shores of the Caspian Sea. It covers a 2,500 km2 (970 sq mi) project license area which also includes a smaller Korolev field as well as several exploratory prospects.
West Qurna is one of Iraq's largest oil fields, located north of Rumaila field, west of Basra. West Qurna is believed to hold 21 billion barrels of recoverable reserves, making it the second largest field in the world after Saudi Arabia's Ghawar oil field.
6 – Bolivar coastal field – Venezuela – 32 billion barrels
Bolivar Coastal Field is the largest oil field in South America with its 6,000-7,000 wells and forest of related derricks, stretches thirty-five miles along the north-east coast of Lake Maracaibo, Venezuela.
7. Prudhoe Bay – Alaska, USA – 25 Billion barrels
Prudhoe Bay Oil Field is a large oil field on Alaska's North Slope. It is the largest oil field in both the United States and in North America, covering 213,543 acres (86,418 ha) and originally containing approximately 25 billion barrels (4.0×109 m3) of oil. The amount of recoverable oil in the field is more than double that of the next largest field in the United States, the East Texas oil field. The field is operated by BP; partners are ExxonMobil and ConocoPhillips Alaska.
8 - Cantarell Field – Mexico – 18 billion barrels
Cantarell Field or Cantarell Complex is an aging supergiant oil field in Mexico. It was discovered in 1976 after oil stains were noticed by a fisherman, Rudesindo Cantarell Jimenez, in 1961. It was placed on nitrogen injection in 2000, and production peaked at 2.1 million barrels per day (330,000 m3/d) in 2003. In terms of cumulative production to date, it is by far the largest oil field in Mexico, and one of the largest in the world. However, production has declined since 2003, falling to 408,000 barrels per day (64,900 m3/d) (April 2012), making it Mexico's second most productive oil field after Ku-Maloob-Zaap
9 – Romashkino field – Russia – 17 billion barrels
The Romashkino field is an oil field in Tatarstan, Russia. Discovered in 1948, it is the largest oil field of Volga-Ural Basin. The field is operated by Tatneft. The field covers approximately 4,200 square kilometres (1,600 sq mi).
10 – Rumailia Field – Iraq – 17 billion barrels
The Rumaila oil field is a super-giant oil field located in southern Iraq, approximately 20 mi (32 km) from the Kuwaiti border. The dispute between Iraq and Kuwait over alleged slant-drilling in the field was one of reasons for Iraq's invasion of Kuwait in 1990.