Ghawar Field is located in Saudi Arabia

Ghawar (Arabic: الغوار) is an oil field located in Al-Ahsa Governorate, Eastern Province, Saudi Arabia. Measuring 280 by 30 km (174 by 19 mi), it is by far the largest conventional oil field in the world, and accounts for more than half of the cumulative oil production of Saudi Arabia. ^[2] 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.

• http://en.wikipedia.org/wiki/Ghawar Field