|Location||Al-Ahsa, Eastern Province|
|Start of production||1951|
|Peak year||2005 (Contested)|
|Current production of oil||5,000,000 barrels per day (~2.5×108 t/a)|
|Current production of gas||2,000×106 cu ft/d (57×106 m3/d)|
|Estimated oil in place||71,000 million barrels (~9.7×109 t)|
|Estimated gas in place||110,000×109 cu ft (3,100×109 m3)|
|Producing formations||Upper/Middle Jurassic, Upper/Lower Permian, Lower Devonian|
|Ghawar Field map and regional setting|
|Regional cross section through Ghawar|
|Oil production at Ghawar, 1993-2003|
Ghawar (Arabic:الغوار) is an oil field located in Al-Ahsa Governorate, Saudi Arabia. Measuring 280 by 30 km (170 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. Relatively little technical information is publicly available, because the company and Saudi government closely guard field performance data and per-field production details. Available information is predominantly historical (pre-nationalization), from incidental technical publications, or anecdotal.
Ghawar occupies an anticline above a basement fault block dating to Carboniferous time, about 320 million years ago; Cretaceous tectonic activity, as the northeast margin of Africa began to impinge on southwest Asia, enhanced the structure. Reservoir rocks are Jurassic Arab-D limestones with exceptional porosity (as much as 35% of the rock in places), sourced from the Jurassic Hanifa formation, a marine shelf deposit of mud and lime with as much as 5% organic material (1% to 7% is considered good oil source rock). The seal is an evaporitic package of rocks including impermeable anhydrite.
Historically, Ghawar has been subdivided into five production areas, from north to south: 'Ain Dar and Shedgum, 'Uthmaniyah, Hawiyah and Haradh. The major oasis of Al-Ahsa and the city of Al-Hofuf are located on Ghawar's east flank, corresponding to the 'Uthmaniyah production area. Ghawar was discovered in 1948 and put on stream in 1951. Some sources claim Ghawar peaked in 2005, though this is strongly contested by the field operators.
Saudi Aramco reported in mid-2008 that Ghawar had produced 48% of its proven reserves
Approximately 60–65% of all Saudi oil produced between 1948 and 2000 came from Ghawar. Cumulative production until April 2010 has exceeded 65 billion barrels (1.03×1010 m3). Currently, Ghawar is estimated to produce over 5 million barrels (790,000 m3) of oil a day (6.25% of global production). 
Ghawar also produces approximately 2 billion cubic feet (57,000,000 m3) of natural gas per day.
In April 2010, Saad al-Treiki, Vice-President for Operations at Aramco, stated in a news conference reported in Saudi media that over 65 billion barrels (10.3 km3) have been produced from the field since 1951. Treiki further stated that the total reserves of the field had originally exceeded 100 billion barrels (16 km3)
When appraised in the 1970s, the field was assessed to have 170 billion barrels (27 km3) of original oil in place, with about 60 billion barrels (9.5 km3) recoverable (1975 Aramco estimate quoted by Matt Simmons). The second figure, at least, was understated, since that production figure has already been exceeded.
See also 
- "Ghawar 01:2005 EXPLORER". Aapg.org. Retrieved 2013-04-15.
- "The Elephant of All Elephants". AAPG.
- Glenn Morton (2004-07-24). "Trouble in the World's Largest Oil Field-Ghawar". Energy Bulletin.
- Donald Coxe (2005-03-31). "Has Ghawar truly peaked?".
- Porter, Adam (April 12, 2005). "Bank says Saudi's top field in decline". English Al-Jazeera. Retrieved 2006-09-05.
- "Saudi Arabia Energy Data, Statistics and Analysis - Oil, Gas, Electricity, Coal". 2008-08-01.
- "based on Croft". Gregcroft.com. Retrieved 2013-04-15.
- The King of Giant Fields by Rasoul Sorkhab, GeoExPro Issue 4, Volume 7, 2010
- "أرامكو: «الغوار» ما زال قويا بـ«100» مليار برميل". 2010.
- Simmons, Matthew (2005). Twilight in the Desert - The coming Saudi oil shock and the world economy. Hoboken, NJ: John Wiley & Sons. ISBN 0-471-73876-X.
- A theoretical look at the future of the field
- Articles on Ghawar and analysis on its reserves from The Oil Drum
- Terrorists and Ghawar
- Saudi Aramco official website (source of most data in this article).
- World-beater Ghawar a field apart, 2008 article in Saudi Aramco Dimensions magazine