Strait of Hormuz
The Strait Of Hormuz [SOH, much less commmonly termed Straits of Hormuz] is the world's second busiest international strait. The key to the Central Command area is to maintain uninterrupted access to energy resources. The Persian Gulf region contains roughly 68% of the world's known oil and natural gas reserves. Nearly 25% of the world's oil supply flows through the Strait of Hormuz on a daily basis. Over 75% of Japan's oil passes through the Strait of Hormuz. Oil flows through the Strait of Hormuz -- daily oil flow of 16.5-17 million barrels (2006E) -- is roughly two-fifths of all seaborne traded oil. The Energy Information Administration projects that oil exports through the Strait of Hormuz will double to 30-34 million barrels per day by 2020, suggesting that ensuring the free flow of oil through the Strait will continue to be an important mission.
The Strait of Hormuz, a narrow waterway separating the Arabian Gulf from the Gulf of Oman and the North Arabian Sea, is only about 40 miles wide, and is 34 miles wide at its narrowest point. By far the world's most important oil chokepoint, the Strait consists of 2-mile wide channels for inbound and outbound tanker traffic, as well as a 2-mile wide buffer zone.
The Persian Gulf is a shallow, semienclosed basin with a mean depth of only 25 to 40 m. The circulation of this basin is driven primarily by the local wind stress and secondarily by thermohaline forcing. The prevailing wind in the Persian Gulf is from the northwest and is called the shamal. A wind-driven generally cyclonic circulation results. The lands surrounding the Persian Gulf are dry so there is strong excess evaporation over the Persian Gulf. This results in a surface inflow of relatively fresh water and an outflow of deeper, more-saline water at the Strait of Hormuz.
The Strait of Hormuz has a very small sill and thus a classic inverse-estuarine circulation dominates the Gulf. Relatively freshwater flows in through the Straits and the more saline water flow uninhibited out of the straits at depth. Some of the highest current speeds are in the inflow through the southern side of the Strait of Hormuz. This inflow feeds the eastward coastal current along the south edge of the Gulf, which is strongest near Qatar. Along the Iranian coast, there is another eastward current where it terminates and its remnant turns south into the interior.
The majority of oil exported from the Strait of Hormuz travels to Asia, the United States, and Western Europe. Currently, three-quarters of all Japan's oil needs pass through this Strait. Most of the crude exported through the Strait travels long distances by Very Large Crude Carriers (VLCC) which can carry over two million barrels of oil per voyage.
If access to the Gulf were denied, assuming pipelines would flow at maximum capacity, the world would lose about one-fifth of its oil supply. Closure of the Strait of Hormuz would require use of longer alternate routes (if available) at increased transportation costs. Such routes include the 5 million-bbl/d capacity Petroline (East-West Pipeline) and the 290,000-bbl/d Abqaiq-Yanbu natural gas liquids line across Saudi Arabia to the Red Sea. Theoretically, the 1.65-million bbl/d Iraqi Pipeline across Saudi Arabia (IPSA) also could be utilized, more oil could be pumped north to Ceyhan (Turkey), and the 0.5 million-bbl/d Tapline to Lebanon could be reactivated.
A US Government Accountability Office (GAO) report of October 5, 2006 concluded that the US Strategic Petroleum Reserve (SPR) was "insufficient" to replace the oil lost from a severe supply disruption, including a global Iranian oil embargo, Strait of Hormuz closure, or a shutdown of the Saudi oil fields due to terrorism. The report noted that an Iranian embargo could cause oil prices to increase by $16 per barrel and up to $200 billion in GDP damage to the US economy, of which $132 billion could be offset by the SPR. A Saudi shutdown could cause $832 billion in damage to the US GDP, of which only $77 billion could be offset by the SPR. GAO estiamted that Strait of Hormuz closure could cause oil prices to increase by $175 per barrel.
Some say it would be foolish for Iran to seek to disrupt oil traffic in the Gulf because all of its oil flows through the Gulf. The US Government doesn't anticipate that Iran would try to do something like that because it would be the first victim of any such program.
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