Google Ghawar, Saudi Arabia
Estimated reserves: 7583 billion barrels
Status: The worlds largest oil field measures a whopping 174 miles long and 16 miles across. Owned by the state oil company Saudi Aramco, Ghawar produces more than half of Saudi Arabias oil and 6 to 8 percent of the worlds crude. Last year, American energy expert Matthew Simmons made Ghawar a prime focus of his book about peak oil and the decline of Saudi Arabian output. At the time, Saudi Aramco pooh-poohed his analysis. But earlier this year, a government spokesman admitted that Ghawars output is indeed falling by about 8 percent per year.
Major vulnerability: H20. More than 200 of the wells in the Ghawar complex are horizontal, a recent innovation of the past two decades that makes it easier to extract oil. In Saudi Arabia, water is pumped into oil fields to build pressure and stimulate oil production. But if water levels in Ghawar creep up to the level of the horizontal wells, oil production there could collapse, crippling the global economy.
Google Burgan, Kuwait
Estimated reserves: 6672 billion barrels
Status: You might recall photos of the Burgan oil field from 1991, when it was set on fire by retreating Iraqi soldiers during the first Gulf War. Burgan has since recovered, yielding as many as 2.2 million barrels per day, or 80 percent of Kuwaits total oil production.
Major vulnerability: Running dry. Burgan has been pumping oil for 60 years and hit its peak production in 2004. Last fall, Farouk Al Zanki, the chairman of Kuwait Oil, said that the fields output would no longer be the estimated 2 million barrels per day, but a more modest 1.7 million barrels. And even that wont last very long. The field is expected to produce for another 30 to 40 years before running dry.
Google/NAVTEQ Cantarell, Mexico
Estimated reserves: 35 billion barrels
Status: First discovered in 1976, this Mexican oil field is actually a large complex of smaller fields. Like its Middle East siblings, Canterell is past its prime, having hit peak production in 2004. Earlier this month, Mexicos state-owned oil monopoly, Petroleos Mexicanos (PEMEX), announced that the fields production will decline 8 percent in 2006, a more rapid drop than the December 2005 estimate of 6 percent.
Major vulnerability: Massive debt. PEMEX, which manages the field, must pay billions in taxes to the Mexican government, providing about one third of the national budget and forcing the company to borrow heavily, to the tune of about $50 billion. No profit means PEMEX cant invest in new technologies that could more efficiently extract crude from Cantarell and replace its aging infrastructure. That means as the field runs dry and crude becomes harder to extracta recent report suggested Cantarells output could decline by as much as 75 percent by the end of 2008much-needed resources will be hard to come by.
Google Bolivar Coastal Complex, Venezuela
Estimated reserves: 3032 billion barrels
Status: The Bolivar Coastal complex accounts for most of Venezuelas oil production, roughly 3 million barrels a day. A 2002 oil workers strike caused a dip in production, but the government reports that its now back to pre-strike levels. External sources beg to differ, claiming the countrys total output is more like 2.6 million barrels.
Major vulnerability: Lack of expertise. President Hugo Chvezs quest to nationalize the oil industry has resulted in the loss of technological expertise that foreign firms can bring to oil extraction. Chvez has already lost many of his homegrown managers. Jorge Pion, an energy researcher at the University of Miami, estimates that Venezuelas state oil company has lost 60 percent of its managerial expertise in the past five years. That could translate into an increase in industrial accidents. Chvez is also fond of using the countrys oil windfalls to finance social programs, whichintentionally or nothave come at the expense of oil field maintenance.
Google Rumaila, Iraq
Estimated reserves: 20 billion barrels
Status: With oil exports providing more than 95 percent of the Iraqi governments revenue, getting the countrys largest oil field back to top production is a major priority. But for several years, output at Rumailanear the Kuwaiti border and one of the fields in dispute during the first Gulf Warhas been in decline, largely because of the second Gulf War and looters. But better security and the new Qarmat Ali water injection system in southern Iraq (built as part of the reconstruction effort) has helped reverse that trend, and production is on the rise once more.
Major vulnerability: Civil war. Looting and sabotage remain tremendous problems for Rumaila, and production is still nowhere near its prewar level. If Iraq isnt stable soon, Rumaila could be years away from making a substantial contribution to the worlds oil output.
Google Tengiz, Kazakhstan
Estimated reserves: 1526 billion barrels
Status: Tengiz is the only field among the worlds top 10 largest oil fields that is actually expected to increase production within the next decade. Discovered in 1974, the Tengiz oil field is 3 miles deep and lies alongside the northeast shore of the Caspian Sea. In the first half of last year, it produced 267,000 barrels per day. Analysts think it has the potential to produce more than twice that amount by 2010.
Major vulnerability: The neighborhood. Most of the oil from Tengiz is currently routed through the Caspian Pipeline Consortium to the Russian port of Novorossiysk on the Black Sea, where Russia takes a cut. The Baku-Tbilisi-Ceyhan Pipeline, which opened last year, bypasses Russia, but theres no direct line to the Tengiz field. With increased production in upcoming years, Kazakhstan (and its neighbors) will have to find new pipelines to export its oil if it wants to cut Russia out as a middleman.