BP Plc started pumping cement into the top of its crippled Gulf of Mexico well, moving closer to permanently plugging the source of the world’s biggest accidental offshore oil spill on record.
“We’ll create a significant milestone and make a major step forward, probably by tomorrow when the cementing is done,” National Incident Commander Thad Allen told reporters today in Washington. “We can all breathe a little easier regarding the potential that we have oil in the Gulf ever again.”
BP pumped mud into the top of its Macondo well earlier this week, pushing back the flow of oil and gas and making the cementing possible. The cement will cure in 24 to 36 hours, and then the company will resume drilling a relief well that aims to permanently plug Macondo from below.
BP temporarily sealed the well on July 15 through a valve stack placed atop Macondo, stopping a leak that spewed 4.9 million barrels of crude since an April 20 drilling-rig explosion, according to a government estimate. The relief well near Macondo will take at least five days to finish drilling its final 100 feet (30 meters).
By filling the well from top to bottom, pushing cement into the oil and gas reservoir, London-based BP will eliminate any possibility of a leak, Allen said. The well is located about 40 miles (64 kilometers) off the Louisiana coast.
BP rose for a fourth straight day, climbing 1.75 pence to 423.4 pence as of 4:35 p.m. in London. The close was its highest since June 7. Before today, the stock had dropped 36 percent since the April rig explosion, which killed 11 workers.
About 74 percent of the oil that flowed from Macondo evaporated, dissolved or biodegraded, or was burned, skimmed or captured, the government said in a report yesterday.
The 26 percent of the well’s oil that’s not accounted for may be on the surface of the water, buried beneath sand and sediment, or was collected from the region’s beaches, according to a report from a team led by the U.S. Interior Department and the National Oceanic and Atmospheric Administration.
BP started pumping mud into the top of Macondo from a vessel on the Gulf’s surface on Aug. 3, bringing the well’s pressure to zero.
“Once you get the mud in and you control the pressure of the well, it’s basically under control, just like any well drilled anywhere in the world that does not have a blowout,” said Don Van Nieuwenhuise, director of petroleum geoscience programs at the University of Houston. “The cement will hold that mud into place.”
The company, which plans to sell up to $30 billion of assets to pay for the spill, said yesterday that it agreed to sell properties in Colombia for $1.9 billion. BP agreed last month to sell $7 billion of fields in the U.S., Canada and Egypt to Apache Corp.