WASHINGTON, (Reuters) – BP Plc said yesterday it  was close to subduing its ruptured Gulf of Mexico oil well, and  the White House hailed the “beginning of the end” of efforts to  contain the worst spill in U.S. history.

After months of setbacks in efforts to permanently plug the  deepsea well, BP said heavy drilling mud injected into it yesterday was stemming the flow of crude.

Buoyed by the success, the company said it was considering  skipping the next planned step in the so-called “static kill”  procedure — pumping in cement as a seal — and waiting to do  it when a relief well was completed in August.

The British energy giant, which has lost about 40 percent  of its market value and seen its image badly tarnished by the  disaster, called it a “significant milestone.”

“The long battle to stop the leak and contain the oil is  finally close to coming to an end,” said President Barack  Obama, whose approval ratings have been hurt by public  discontent over his administration’s handling of the spill.

BP’s mile-deep Macondo well ruptured after an oil rig  exploded and sank in April, leaking millions of barrels of oil  into the ocean for nearly three months in the world’s worst  accidental marine spill.

The static kill is part of a two-pronged strategy to kill  the well for good. The relief well is seen as the final  solution. After it intercepts with the ruptured well shaft, mud  and cement will be pumped in to plug the oil reservoir 13,000  feet (4,000 metres) beneath the seabed.

As BP reported success in the Gulf, a team of government  scientists said about 50 percent of the spilled oil had been  captured, evaporated, burned or skimmed, while another quarter  had been naturally or chemically dispersed.

The rest was either on or just beneath the water’s surface  as “light sheen or weathered tarballs,” had washed ashore or  was buried in sand and sediments at the sea bottom, they said.

The financial implications for BP’s continued cleanup  efforts were not immediately clear. Government officials have  said in the past that it will take years to fully repair the  damage inflicted by the spilled oil, which seeped into  ecologically sensitive wetlands and marshes.

Despite the good news from the Gulf, BP shares in New York  slid 1.5 percent amid apparent profit-taking by investors.