Ghawar Field

Ghawar is an oil field located in Al-Ahsa Governorate, Eastern Province, Saudi Arabia. Measuring 280by, 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. 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, from incidental technical publications, or anecdotal.GeologyGhawar 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), which is about 280 feet thick and occurs 6,000-7,000 feet beneath the surface. Source rock is 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.