By
updated 8/5/2010 7:16:17 PM ET 2010-08-05T23:16:17

BP finished pumping fresh cement into its blown-out oil well Thursday as it aimed to seal for good the ruptured pipe that for months spewed crude into the Gulf of Mexico in one of the world's worst spills.

A day before, crews forced a slow torrent of heavy mud down the broken wellhead from ships a mile above to push the crude back to its underground source. The cement was the next step in this so-called "static kill" and is intended to keep the oil from finding its way back out.

"This is not the end, but it will virtually assure us that there will be no chance of oil leaking into the environment," retired Adm. Thad Allen, who oversees the spill response for the government, said in Washington.

The progress was another bright spot as the tide appeared to be turning in the months-long battle to contain the oil, with a federal report this week indicating that only about a quarter of the spilled crude remains in the Gulf and is degrading quickly.

Even so, Joey Yerkes, a 43-year-old fisherman in Destin, Fla., said he and other boaters, swimmers and scuba divers continue to find oil and tar balls in areas that have been declared clear.

"The end to the leak is good news, but the damage has been done," Yerkes said.

If the mud plug in the blown-out well is successfully augmented with the cement, the final step involves an 18,000-foot relief well that intersects with the old well just above the vast undersea reservoir that had been losing oil freely since the Deepwater Horizon rig exploded off Louisiana on April 20, killing 11 workers.

The hope has been to pump mud and possibly cement down the relief well after its completion later this month, supplementing the work in this week's static kill and stopping up the blown-out well from the bottom.

It could take at least a day for the cement pumped into the blown well to dry, and another five to seven days for crews to finish drilling the final 100 feet of the relief well. Then the pumping process in the relief well could last days or even weeks, depending on whether engineers find any oil leaks, Allen said.

Despite the progress on the static kill, BP executives and federal officials won't declare the threat dashed until they use the relief well — though lately they haven't been able to publicly agree on its role.

Federal officials including Allen have insisted that crews will shove mud and cement through the 18,000-foot relief well, which should be completed within weeks. Crews can't be sure the area between the inner piping and outer casing has been plugged until the relief well is complete, he said.

But for reasons unclear, BP officials have in recent days refused to commit to pumping cement down the relief well, saying only that it will be used in some fashion. BP officials have not elaborated on other options, but those could include using the well simply to test whether the reservoir is plugged.

"We have always said that we will move forward with the relief well. That will be the ultimate solution," BP Senior Vice President Kent Wells said Wednesday afternoon. "We need to take each step at a time. Clearly we need to pump cement. If we do it from the top, we might alter what we do with the relief well, but the relief well is still a part of the solution. The ultimate objective is getting this well permanently sealed."

The game of semantics has gone back and forth this week, with neither yielding.

Allen clearly said again Thursday that to be safe, the gusher will have to be plugged up from two directions, with the relief well being used for the so-called "bottom kill."

"The well will not be killed until we do the bottom kill and do whatever needs to be done," he said, adding: "I am the national incident commander and I issue the orders. This will not be done until we do the bottom kill."

BP shares rose 2.7 percent to $40.46 in morning trading in New York. At one point they reached $40.75, their highest level since May 28.

Whether the well is considered sealed yet or not, there's still oil in the Gulf or on its shores — nearly 53 million gallons of it, according to the report released Wednesday by the Interior Department and the National Oceanic and Atmospheric Administration. That's still nearly five times the size of the Exxon Valdez spill, which wreaked environmental havoc in Alaska in 1989.

But almost three-quarters of the nearly 207 million gallons of oil that leaked overall has been collected at the well by a temporary containment cap, been cleaned up or chemically dispersed, or naturally deteriorated, evaporated or dissolved, the report said.

  1. Click here for related content
    1. BP to begin forcing cement down well
    2. Some experts skeptical of Gulf oil findings
    3. Newsweek: What the report really says
    4. BP: 'Static kill' working, mud holds well shut
    5. SEC probes BP potential insider trading
    6. EPA study: BP dispersant less toxic than oil

The remaining oil, much of it below the surface, remains a threat to sea life and Gulf Coast marshes, NOAA Administrator Jane Lubchenco said. But the spill no longer threatens the Florida Keys or the East Coast, the report said.

Some outside experts have questioned the veracity of the report, with at least one top federal scientist warning that harmful effects could continue for years even with oil at the microscopic level.

But Allen said the estimates are based on the best data scientists had available and that they could be "refined" as more research is completed.

"Models are an approximation of reality and are therefore never perfect," he said.

An experimental cap has stopped the oil from flowing for the past three weeks, but it was not a permanent solution.

The static kill — also known as bullheading — probably would not have worked without that cap in place. It involves slowly pumping the mud and now the cement from a ship down lines running to the top of the ruptured well a mile below. A similar effort failed in May when the mud couldn't overcome the flow of oil.

© 2013 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Video: BP finishes pumping cement into Gulf well

  1. Transcript of: BP finishes pumping cement into Gulf well

    LESTER HOLT, anchor: Want to turn now to the Gulf of Mexico with the news everyone has been waiting for since April 20th , when the Deepwater Horizon drilling rig exploded. The well has been sealed shut with cement. NBC 's Anne Thompson has been covering this oil disaster since the beginning. She joins us now from Venice , Louisiana . Anne , I thought we'd never hear those words.

    ANNE THOMPSON reporting: Boy, I certainly didn't. There was a time I doubted it, Lester , but we do have very good news tonight, and that is that this well is cemented shut from the top. It took five hours to do that. And for the first time in 108 days, officials say the people of the Gulf of Mexico can be assured that virtually no oil from the Macondo well will leak into their waters. However, that's not the end of the story. National incident commander Thad Allen has ordered BP to cement the well from the bottom as well, and BP says it will do that through the relief well process, which could start as early as next week.

    Lester: Anne , what about the oil collection process, given there's still a lot of oil in the gulf? Does this now add more resources as they wind down at that well site itself?

    HOLT: They get to shift the resources. Instead of having all those large skimmers that they've had out at the leak site as a precautionary measure since July 15th , when they temporarily capped the well, they'll now start to bring those in shore, and they can now start to focus on the in shore efforts more heavily than they have before. Lester :

    THOMPSON: Anne Thompson , thank you.

    HOLT:

Interactive: Interactive look at 'static kill'

Photos: Month 4

loading photos...
  1. The Blue Dolphin, left, and the HOS Centerline, the ships supplying the mud for the static kill operation on the Helix Q4000, are seen delivering mud through hoses at the site of the Deepwater Horizon Oil Spill in the Gulf of Mexico, off the coast of Louisiana, on Aug. 3, 2010. In the background is the Development Driller III, which is drilling the primary relief well. (Gerald Herbert / AP) Back to slideshow navigation
  2. Eddie Forsythe and Don Rorabough dump a box of blue crabs onto a sorting table at B.K. Seafood in Yscloskey, La., on Aug. 3, 2010. The crabs were caught by fisherman Garet Mones. Commercial and recreational fishing has resumed, with some restrictions in areas that were closed by the Deepwater Horizon oil spill. (Chuck Cook / AP) Back to slideshow navigation
  3. Sea turtle hatchlings that emerged from eggs gathered on the northern Gulf Coast of Florida are released at Playalinda Beach on the Canaveral National Seashore near Titusville, Fla., on Aug. 2, 2010. The sea turtles were born at a Kennedy Space Center incubation site, where thousands of eggs collected from Florida and Alabama beaches along the Gulf of Mexico have been sent. (Craig Rubadoux / Florida Today via AP) Back to slideshow navigation
  4. A crab, covered with oil, walks along an oil absorbent boom near roso-cane reeds at the South Pass of the Mississippi River in Plaquemines Parish, Louisiana on Aug. 1, 2010. BP is testing the well to see if it can withstand a "static kill" which would close the well permanently. (Pool / Reuters) Back to slideshow navigation
  5. A boat motors through a sunset oil sheen off East Grand Terre Island, where the Gulf of Mexico meets Barataria Bay on the La. coast, on the evening of July 31. (Gerald Herbert / AP) Back to slideshow navigation
  6. Oil approaches a line of barges and boom positioned to protect East Grand Terre Island, partially seen at top right, on July 31. (Gerald Herbert / AP) Back to slideshow navigation
  7. Oil from the Deepwater Horizon oil spill is seen near an unprotected island in the Gulf of Mexico near Timbalier Bay, off the coast of Louisiana on Wednesday, July 28. (Gerald Herbert / AP) Back to slideshow navigation
  8. Greenpeace activists stand outside a BP gas station in London, England, on July 27 after they put up a fence to cut off access. Several dozen BP stations in London were temporarily shut down to protest the Gulf spill. (Leon Neal / AFP - Getty Images) Back to slideshow navigation
  9. James Wilson sells T-shirts to those arriving in Grand Isle, La., for the music festival Island Aid 2010 on July 24. (Dave Martin / AP) Back to slideshow navigation
  10. Activists covered in food coloring made to look like oil protest BP's Gulf oil spill in Mexico City on July 22. The sign at far left reads in Spanish "Petroleum kills animals." (Alexandre Meneghini / AP) Back to slideshow navigation
  11. People in Lafayette, La., wear "Keep Drilling" tee shirts at the "Rally for Economic Survival" opposing the federal ban on deepwater drilling in the Gulf of Mexico on Wednesday, July 21. Supporters at the rally want President Obama to lift the moratorium immediately to protect Louisiana's jobs and economy. (Ann Heisenfelt / EPA) Back to slideshow navigation
  12. A flock of white ibis lift off from marsh grass on Dry Bread Island in St. Bernard Parish, La., July 21. Crews found about 130 dead birds and 15 live birds affected by oil from the Deepwater Horizon oil spill on July 19 in the eastern part of the parish behind the Chandeleur Islands. (Patrick Semansky / AP) Back to slideshow navigation
  13. Kenneth Feinberg, administrator of the BP Oil Spill Victim Compensation Fund testifies during a hearing before the House Judiciary Committee on July 21 in Washington, D.C. The hearing was to examine the claim process for victims of the Gulf Coast oil spill. (Alex Wong / Getty Images) Back to slideshow navigation
  14. An American white pelican has its wings checked during a physical examination at Brookfield Zoo’s Animal Hospital by Michael Adkesson and Michael O’Neill on July 21. The bird, along with four other pelicans, was rescued from the Gulf Coast oil spill and will be placed on permanent exhibit at the zoo. (Jim Schulz / Chicago Zoological Society via AP) Back to slideshow navigation
  15. Native people of the Gwich'in Nation form a human banner on the banks of the Porcupine River near Ft. Yukon, Alaska July 21, in regard to the BP oil spill with a message to protect the Arctic National Wildlife Refuge from oil development. The images include a Porcupine caribou antler and a threatened Yukon River Salmon. (Camila Roy / Spectral Q via Reuters) Back to slideshow navigation
  1. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.

  2. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.

  3. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.

  4. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.

  1. Image:
    Gerald Herbert / AP
    Above: Slideshow (15) Oil spill disaster in the Gulf - Month 4
  2. Image: Economic And Environmental Impact Of Gulf Oil Spill Deepens
    Mario Tama / Getty Images
    Slideshow (64) Oil spill disaster in the Gulf - Month 3
  3. Image: Oil Spill In The Gulf
    Digitalglobe / Getty Images Contributor
    Slideshow (81) Oil spill disaster in the Gulf - Month 2
  4. Image: Dispersed oil caught in the wake of a transport boat floats on the Gulf of Mexico
    Hans Deryk / Reuters
    Slideshow (53) Oil spill disaster in the Gulf - Month 1
  5. Image:
    Gerald Herbert / AP
    Slideshow (10) Oil spill disaster in the Gulf - Rig explosion

Discuss:

Discussion comments

,

Most active discussions

  1. votes comments
  2. votes comments
  3. votes comments
  4. votes comments