Permanent seal of well delayed amid new reports that 79% of the oil remains the Gulf

A group of scientists have found that up to 79% of the oil in the Gulf of Mexico may still remain, contradicting earlier findings by a U.S. government study that found nearly 75% of the oil had dissipated.

Although the new estimate is based on the same data used by the U.S. government's study, the researchers came to radically different conclusions.

Bloomberg reports,

A group of scientists says as much as 79 percent of BP Plc’s leaked oil remains in the Gulf of Mexico, challenging an Obama administration assessment that the crude is largely gone or rapidly disappearing.

Most of the oil that leaked from BP’s Macondo well from April 20 to July 15 is still beneath the water’s surface, scientists including Samantha Joye, a professor of marine sciences at the University of Georgia in Athens, concluded in a memo made public yesterday. The researchers say they drew upon the U.S. government’s study while reaching different conclusions.

The Obama administration’s Aug. 4 report indicated that almost three-fourths of the crude that leaked has disappeared or soon will be eaten by bacteria. Jane Lubchenco, administrator of the National Oceanic and Atmospheric Administration, has said at least half of the oil released is now “completely gone.”

(Original AFP story follows)

As new reports indicate oil is not dissipating as quickly as was first thought, a long-standing deadline for sealing the ruptured Gulf of Mexico well deep below the seabed will be missed as US officials and BP tackle concerns about debris lodged in the well.

BP and US government representatives had hoped to complete a "bottom kill" procedure and officially pronounce the well dead by mid-August, but the US pointman on the oil spill response said Monday the bid was on hold.

Admiral Thad Allen said that an earlier successful process sealing the well from above may have wedged cement between two layers of casing, trapping leaked crude inside the void.

That has forced officials to put on hold plans to seal the well from below by flushing first a heavy drilling fluid called "mud" and then cement into the damaged structure via an intercept from a second relief well.

"When we do the intercept well and commence pumping mud and cement... it will create pressure," Allen said.

"We want to make sure before I give the order and direct BP to do that, that we know the implications of that pressure, and how we will deal with it."

BP is now studying two alternatives ways to tackle the potential problems posed by the debris and trapped crude.

The first is a "pressure relief method" that would work with the sealing cap currently atop the well; the alternative would involve bringing in a new blow-out preventer device to withstand any pressure caused by the blockage.

"I believe that we should have pretty much exhausted all the alternatives of what it would take to do all of this sometime in the next day or a two at a maximum and we'll be able to announce a decision," Allen said Monday.

"I would say approximately seven days after I direct them to move ahead we would finish the pressure test and declare the well dead."

The setback will be disappointing for weary Gulf Coast residents eager for the psychological relief of knowing a final death blow has been struck against a well that has unleashed such economic and environmental catastrophe.

The Macondo well has not spilled crude since July 15, when a sealing cap was successfully closed over the leak, providing the first concrete success in efforts to contain the gushing crude.

The spill, the worst in US history, was sparked April 20 by an explosion that ripped through the BP-leased Deepwater Horizon oil rig, killing 11 workers and sinking the platform two days later.

(With AFP report)