NEW YORK (MarketWatch) -- BP PLC moved closer Monday to bringing to heel the Gulf of Mexico gusher that ranks as the worst spill in U.S. history, but officials acknowledged that more equipment is needed to process the huge flow of oil and natural gas coming from the ruptured well.

U.S. Coast Guard Adm. Thad Allen said BP BP, -1.18% (BP) is now capturing about 11,000 barrels of oil a day from a containment cap lowered onto the riser pipe late last week, but more oil continues to billow out into the water from unclosed vents on the cap, as well as from broken parts of the seal.

BP will bring in a second processing facility to handle the mix of oil, gas and seawater coming from the well, Allen said during a press conference at the White House.

"The second vessel is on its way," Allen said.

President Barack Obama said the economic impact of the spill will be "substantial" and that oil will continue to leak "even if the containment effort is completely successful."

Last month, a team of scientists led by the U.S. Geological Survey put the top end of the projected daily rate of flow at 25,000 barrels. But when BP cut the riser pipe to prepare it for the containment cap last week, officials said the move would have the effect of undoing a crimp in the pipe and increase the flow by up to 20% more.

Allen said the government's flow rate technical group is now working on a revised estimate of the size of the spill in order to assess penalties that BP will have to pay. The massive spill began after the Deepwater Horizon rig exploded on April 20, killing 11 workers and triggering an environmental disaster in the Gulf of Mexico. The rig sank two days later.

Robert Gibbs, the White House press secretary, said BP will likely be on the hook for "many billions" of dollars.

As Wall Street continued to crunch numbers on what the cost of the spill will be for BP investors, Goldman Sachs analysts took the figures spent by Exxon Corp., now Exxon Mobil XOM, +0.14% , in the 1989 Exxon Valdez accident, and adjusted them for inflation to come up with a figure of $40,000 per barrel spilled.

Analysts projected a total spill of 800,000 barrels and a cost of $36 billion to BP -- in line with earlier Wall Street estimates of up to $40 billion.

Allen said the government is now battling "hundreds of thousands" of patches of oil both at sea and that have washed up between Louisiana and Port St. Joe on Florida's Gulf Coast.

Goldman downgrades BP

Meanwhile, BP said the spill has cost it more than $1.25 billion thus far, while the Coast Guard expects cleanup efforts to last for months.

BP decided Sunday to keep some of the four vents open on the cap over its leaking well a mile below the surface of the Gulf because it didn't have enough processing capacity to handle the mix of sea water and oil coming from the gusher, according to a New York Times report.

The Discoverer Enterprise drill ship at the site is equipped to handle up to 15,000 barrels a day.

On the investment front, Goldman Sachs analysts downgraded its rating on shares of BP to neutral from buy.

Analysts said Monday that it's impossible to know the full costs of the spill at this point but that they may not fully materialize for a decade, subject to extensive legal wrangling.

BP could handle about $11 billion in cleanup costs before resorting to a dividend cut or a rights issue to stoke bolster its cash holdings, Goldman Sachs said.

About 27% of BP's global production comes from the U.S., with the Gulf of Mexico along contributing 14% of its total production, analysts noted.

"Beyond the cost of the spill and the potential pressure this could place on the dividend, we believe the spill will cause reputational damage, impacting BP's ability to do business and compete as an operator in the Gulf of Mexico, in the U.S. and globally, Goldman Sachs said.

Separately, Goldman is leading efforts to fend off any potential takeover attempts for the U.K. oil major, according to a report in the Independent on Sunday.

Goldman, as BP's regular advisor, is "rumored to be dusting off the company's defense playbook," the newspaper said.