American units advancing west of the southern city of Basra secured the Rumeila field, whose daily output of 1.3 million barrels makes it Iraq's most productive. Coalition forces also discovered that only seven oil wells were on fire in southern Iraq -- far fewer than many officials had feared, although smoke could be seen in photos taken by satellites.
"All the key components of the southern oil fields are now safe," Adm. Michael Boyce, chief of the British defense staff, told reporters in London. "We have specialist civilian contractors on their way who will be in the area very shortly, in a day or two, to deal with the oil well fires."
In Washington, Defense Secretary Donald Rumsfeld told reporters that "only about 10 wells that we know of, out of possibly 1,000 in that area," had been damaged.
Air Force Gen. Richard Myers, chairman of the Joint Chiefs of Staff, said allied troops seized the port city of Umm Qasr in the al-Faw peninsula along with the main oil conduits along the al-Faw waterways. They also were sweeping through the southern Iraqi oil fields.
In one of the first moves of the ground assault Thursday, U.S. and British troops captured the tip of the strategic al-Faw peninsula, a gathering point for the pipelines that carry crude from southern Iraq to the export terminals of Mina al-Bakr and Khor al-Amaya in the Persian Gulf.
British Defense Secretary Geoff Hoon told the House of Commons that most of the al-Faw oil facilities were intact.
If the terminals in al-Faw — including facilities for shipping, storing and loading crude — have been secured undamaged, "that's more important than preventing the oil wells from being blown," said Leo Drollas, chief economist of the Center for Global Energy Studies in London.
Iraq has the world's second-biggest proven crude reserves and typically pumps about 2.5 million barrels a day, or 3 percent of global supplies. More than half its output comes from Rumeila and other fields near Basra.
The capture of much of the oil infrastructure in southern Iraq helped ease concerns in a volatile oil market, which had fearwed Iraqi President Saddam Hussein might destroy many oil wells to deny their use by a U.S.-backed successor government.
May contracts of North Sea Brent, Europe's benchmark price for crude, fell by $1.15 a barrel to $24.35 in London. Contracts of U.S. light, sweet crude for May delivery were $1.12 lower at $27.00, in New York. U.S. crude prices have dropped sharply since Feb. 27, when they reached a 12-year peak of $39.99.
Witnesses near the city of Kirkuk, the center of the oil industry in northern Iraq, reported hearing explosions and anti-aircraft fire late Friday. The Kirkuk oil field produces about 700,000 barrels a day, most of which is exported via a pipeline to the Mediterranean port of Ceyhan, Turkey.
With only seven wells out of a total 1,685 known lost to sabotage, the nightmare scenario of wholesale destruction of the Iraqi oil fields was becoming more remote, analysts said.
"You lose 50 oil wells? Big deal," said Peter Gignoux, head of the oil desk at Salomon Smith Barney in London. "If the whole pipeline system and the loading facilities in the south are intact, then Iraq is half self-sufficient already."