Ghawar Field

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Ghawar
Country:	Saudi Arabia
Coordinates:	25.010951° N 49.334106° ECoordinates: 25.010951° N 49.334106° E
Offshore/Onshore:	Onshore
Operators:	Saudi Aramco

Field History
Discovery:	1948
Start of production:	1951
Peak of production:	2005 (contested)
Production
Current Production Oil (Bod):	5 Mbbl/d (790,000 m³/d)
Producing Formations:	Upper/Middle Jurassic, Upper/Lower Permian, Lower Devonian

This article is about an oil field. For the similarly pronounced mathematical sense, see Galois field.

Ghawar is an oil field in Saudi Arabia. It is located about 100 km WSW from the city of Dhahran in Al-Ahsa county of the Eastern Province. Measuring 280 km by 30 km, it is by far the largest conventional oil field in the world.^[1] The field is entirely owned and operated by Saudi Aramco, the nationalized Saudi oil company. Relatively little is known about Ghawar because the company and Saudi government closely guard field performance information and per-field production details. Available information is predominantly historical (pre-nationalization), from incidental technical publications, or anecdotal.

1 Geology
2 History
3 Production
- 3.1 Field Reserves
4 See also
5 References
6 External links

[edit] Geology

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 2% is considered good oil source rock). The seal is an evaporitic package of rocks including impermeable anhydrite.

[edit] History

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.^[2]^[3] Some sources claim Ghawar peaked in 2005, though this is strongly contested by the field operators.^[4]^[5]

[edit] Production

The Ghawar Field is the largest known field in the world

Approximately 60-65% of all Saudi oil produced between 1948 and 2000 came from Ghawar. Cumulative production to the end of 2005 was about 60 billion barrels.^[6] Currently, Ghawar is estimated to produce over 5 million barrels (800,000 m³) of oil a day (6.25% of global production).

Ghawar also produces approximately 2 billion cubic feet (57 Mm³) of natural gas per day.

[edit] Field Reserves

Saudi Aramco has stated that it has more than 71 billion barrels (11,300,000,000 m³) of proven reserves remaining. Matthew Simmons, in his book Twilight in the Desert, suggests that production from the Ghawar field and Saudi Arabia, may soon peak.^[7]

When appraised in the 1970s, the field was assessed to have 170 billion barrels (27,000,000,000 m³) of original oil in place, with about 60 billion barrels (9,500,000,000 m³) recoverable (1975 Aramco estimate quoted by Matt Simmons). The second figure, at least, was understated, since that production figure has already been exceeded.^[7]