The end of the beginning.

BP has confirmed a ‘static kill’ operation at the ruptured Gulf of Mexico oil well has been a success, allowing the beleaguered giant to take a significant step toward permanently sealing it.

Following an eight-hour operation at the site, heavy drilling fluid – known in the industry as mud – was poured into the well, forcing the oil back down toward the reservoir.

The operation has allowed BP to assume control of the pressure of the well, which was “the desired outcome”, said a statement.

“The well pressure is now being controlled by the hydrostatic pressure of the drilling mud, the desired outcome of the static kill procedure,” added the statement.

However, the situation was still being monitored.

“The well is now being monitored, per the procedure, to ensure the well remains static,” added BP.

“Further pumping of mud may or may not be required depending on the results observed during monitoring.”

Breakthrough

The breakthrough came 106 days after an explosion aboard the BP-leased Deepwater Horizon rig on April 20th.

The disaster killed 11 workers and unleashed the biggest oil spill in history.

Tourism along the south coast of America has been devastated, with BP facing a flood of litigation following the accident.

Historic Impact

Some 4.9 million barrels of oil are now thought to have leaked into the ocean around the site, posing a significant threat to fish and wildlife-rich US Gulf coast.

The extent of the spill was confirmed earlier this week when US government experts said oil had been pouring out at a rate of 62,000 barrels a day - more than 12 times faster than BP originally admitted.

Following discussions with the Obama administration, the company has suspended dividends until at least the third quarter of financial 2010 and assigned $20 billion to compensate victims of the spill.

BP has also continued to drill two relief wells to the site.

Thad Allen, the Coast Guard admiral overseeing the American government’s response to the spill, explained: “Drilling into the annulus and into the casing pipe from below, filling that with mud and then filling that with cement is the only solution to end this.”

Clean Up

The news comes as White House energy advisor Carol Browner revealed “the majority” of the oil spilled into the Gulf of Mexico had been cleaned up.

“The scientists are telling us about 25 per cent of the oil was not captured or evaporated or taken care of by mother nature,” Ms Browner explained on the ABC television network.

Ms Browner added a report, which will be released today, was “encouraging”.

However, further work will be necessary to repair the damage caused by the spill.

Three quarters of the 4.9 million barrels of oil spilt have been captured, burned off, or evaporated.