SAUDI ARABIA - The Ghawar Fields.
Discovered in 1948 by the then US-owned Aramco (Chevron, Texaco, Exxon & Mobil), Ghawar is by far the largest axis of fields in the world and is the main producer of Arab Light in Saudi Arabia. It is 250 km long and 15 km wide. It contains several fields, of which eight are major oil producers, and huge fields of natural gas in a Khuff reservoir deep beneath the oil formations. Ghawar's proven recoverable oil reserves exceed 70 bn barrels. Oil in place is over 300 bn barrels.
It was Exxon which found the first Ghawar structure at Ain Dar in 1948, having joined Aramco in 1947. It led to discovery and development of other fields by Exxon. The bulk of Ghawar's currently produced oil reserves occur in limestones of the Jurassic Arab A, B, C and D units, mostly at a depth of 6,920 feet, with substantial amounts in older Jurassic limestone members. Beneath them lie giant Khuff and pre-Khuff gas formations.
The main oil producing Ghawar fields are, from north to south: Ain Dar, Shedgum, Uthmaniyah, Farzan, Ghawar, Al Udayliyah, Hawiyah and Haradh. Their installed capacity is 5.3m b/d, of which most of the heavier oil production streams have been mothballed. It was said in early 1990, when total Saudi capacity was less than 8m b/d, these fields still had the potential to produce 4m b/d, as some of the wells were filled with diesel to keep them ready. In 1980, as Saudi Arabia's output totalled 9.9m b/d, Ghawar at times produced over 6.5m b/d; but the reserver was damaged as a result, and now some of the older fields like Ain Dar have begun to decline and need EOR facilities. Haradh, in the southern part of Ghawar, would also require extensive EOR facilities in the coming years. The main boost to Arabian Light capacity has come from the 520,000 b/d expansion at Hawiyah. A $2 bn, 1,440 MCF/d gas processing plant being built at Hawiyah, will be on stream in late 2001 as the 4th in the Master Gas System (MGS). Hawiyah is rich in natural gas and condensates. On July 21, 1994, the Hawiyah-200 exploratory well yielded 20.2 MCF/d of sweet gas and 3,286 b/d of condensates from an interval of 13,650-14,353 feet. The well was spudded in January 1994 and was the first in a series of deep tests to explore new gas reserves on the flanks of Ghawar. It encountered zones bearing extensive sour and sweet gas deposits in a Khuff formation at 12,500 feet.
