June 15th, 2010
11:45 PM ET

How the oil-disaster flow estimates have evolved

U.S. government officials on Tuesday said they now estimate the ruptured BP well in the Gulf of Mexico is spewing 35,000 and 60,000 barrels (1.5 million gallons to 2.5 million gallons) per day; that's significantly more than the first estimate of 1,000 barrels per day in late April.

Below is a recap of the different estimates that officials have made, and when they made them, since the disaster began with the explosion of the Deepwater Horizon oil rig on April 20.

- April 23: Three days after the explosion of the Deepwater Horizon rig, and one day after the rig sank, Coast Guard Rear Adm. Mary Landry said crews were cleaning up a 1- by 12-mile-long oil slick spreading through Gulf waters. She said crude oil did not appear to be leaking out of the wellhead but that remote vehicles would survey the scene. BP officials had said a day earlier that BP they did not know whether oil or fuel was leaking from the rig. But BP Vice President David Rainey said: "It certainly has the potential to be a major spill."

- April 24: Landry said oil was leaking from two places - later to be clarified as two places on the riser pipe extending from the well's blowout preventer - at a preliminary estimate of about 1,000 barrels (42,000 gallons) a day. Officials later said that the two leaks were found within 36 hours of the April 20 explosion.

- April 28: Landry said the estimated amount of oil spilling into the Gulf of Mexico has increased to 5,000 barrels (210,000 gallons) a day, five times the initial estimate. The new estimate was based on analysis from the federal National Oceanic and Atmospheric Administration, she says. Also, BP official Doug Suttles said the company has found a third leak in the riser pipe.

- May 2: Coast Guard Commandant Adm. Thad Allen said it was impossible so far to know how much oil will eventually leak.

"We lost a total well head; it could be 100,000 barrels [4.2 million gallons] or more a day," Allen told CNN's "State of the Union." The official estimate, though, remained at 5,000 barrels (210,000 gallons) a day.

"This spill, at this point in my view, is indeterminate," Allen said. "That makes it asymmetrical, anomalous and one of the most complex things we've ever dealt with."

- May 13: After BP released underwater video footage of the leak, independent experts such as Purdue University associate professor Steve Wereley said the flow rate is probably much higher than the official estimate.

Wereley estimated that about 70,000 barrels (2.94 million gallons) of oil were leaking each day, based on an analysis of video of the spill. "You can't say with precision, but you can see there's definitely more coming out of that pipe than people thought," he said. "It's definitely not 5,000 barrels a day."

- May 27: A panel of government experts estimated the well is spewing oil at a rate of 12,000 to 19,000 barrels (504,000 to 798,000 gallons) a day, U.S. Geological Survey chief Marcia McNutt said.

- June 10: The panel of government experts, called the Flow Rate Technical Group, estimated the well was leaking 20,000 to 40,000 barrels (840,000 to 1.7 million gallons) per day through June 3. The figure was calculated in part by using high-definition video that BP released after demands from members of Congress.

The new estimate was of the well's flow rate before BP's cutting of the damaged riser pipe extending from the well's blowout preventer on June 3, McNutt said. After BP cut the riser that day, it placed a containment cap over the preventer's lower marine riser package to capture some of the leaking oil.

Scientists estimated that the spill's flow rate increased by 4 to 5 percent after the well's riser pipe was cut last week in order to place the cap atop the well.

BP said that with the cap, it was capturing about 16,000 barrels daily and sending it to a ship on the surface. Before that, BP was capturing some oil through a siphon inserted into the well riser.

- June 15: Government officials increased the estimate to between 35,000 and 60,000 barrels (1.5 million gallons to 2.5 million gallons) per day.

The change was "based on updated information and scientific assessments," the Deepwater Horizon Incident Joint Information Center said.

"The improved estimate is based on more and better data that is now available and that helps increase the scientific confidence in the accuracy of the estimate," it said.

soundoff (141 Responses)
  1. Michael

    We'd know exactly how much oil was gushing out if BP would just tell us. You could have written this article with two words: "BP lies."

    June 16, 2010 at 9:23 pm | Report abuse |
  2. CGW Texas

    I'm sorry , but am I missing something here. Did not the flow from the well go on shore or to ship and did not BP have records of production per unit of time at a given pressure. Why all of the estimates?
    If the petroleum companies don't know the flow of the wells they have then they are in poor shape and in the wrong business.
    Wouldn't you think quite a few people would know the production rate at a give point in time at a given pressure?
    I don't see how BP doesn't know how much the well was producing or could produce – regardless of the rate at which BP allowed flow from the well. So, basically , everyone is saying BP has an unknown asset – – I don't think so!
    I feel certain tha BP very well knows +/- 3 % how much that well could produce per minute.
    That well produces X PSI of pressure of oil and gas and X volume oil and MMCF of gas per unit of time.
    This is all absurd to think BP does not know the asset value and physical dimension of the asset.

    June 16, 2010 at 9:24 pm | Report abuse |
    • jimmlca

      They were in the process of drilling this well. It wasn't in production yet. Based on much of the commentary from the crew, they were running into far more gas pressure than normal (2x more than 'extreme') and continued drilling. What we're seeing is the "Gusher" of Hollywood fare... they got deep enough that the and couldn't handle what they got to the point that it blew up their rig.

      June 16, 2010 at 10:23 pm | Report abuse |
    • iggy2010

      No, they did not know the flow rates. This was a NEW WELL, just being brought into production. This is why the mud and concrete work had just been done days and weeks before the blowout.

      Regarding measurements of the flow rates: I am a research scientist, and BP's claim that "they didn't care about the flow rate, they were too busy trying to stop the leak" is so much BS it is insulting to the entire world. If you had a leaky pipe, wouldn't you want to know if the water was leaking from a straw, a water faucet, a garden hose, a fire hose, a fire hydrant, a water main, or Hoover Dam? OF COURSE YOU WOULD!!

      I found it interesting that Prof Werely (Purdue) IMMEDIATELY produced an estimated of 70,000 barrels within a day or two of the FIRST video release by BP. (A) Why did it take 3 weeks for him (or anyone else) to get this information from BP???? Obviously, they were stonewalling. Then they gave out low-res video that was difficult to work with. In the meantime, everyone else was estimating 1,000 to 5,000, then 12,000-19,000, then 20,000-40,000, and ANOTHER MONTH LATER, 35,000 to 60,000 barrels a day. Surprisingly close to the original estimate of 70,000, isn't it?

      I'm glad Obama got $20B out of them (for starters). In particular, BP must pay the oil worker that are out of work due to the moratorium in the Gulf, while everyone (including the Gov't inspectors!) go back to the drawing board to get this right. This will take at least some of the political pressure away from drilling a bunch more wells with no hope of solving future leaks.

      June 16, 2010 at 10:37 pm | Report abuse |
    • ar

      BP does indeed have date on the well's production, and here is the web site...
      They tested up to 9000 barrels/day, but that was with a ~ 1 inch choke.
      Since the lower seal broke, there is no choke now...

      June 17, 2010 at 12:52 am | Report abuse |
    • ar


      BP does indeed have data on the well's production, and here is the web site...
      They tested up to 9000 barrels/day, but that was with a ~ 1 inch choke.
      Since the lower seal broke, there is no choke now, it's just running away wide open. If the well bore erodes and they can't get enough mud into the wellbore to stop it, it's going to turn into an oil volcano. It could leak an Exxon Valdez a week for over a decade...

      June 17, 2010 at 12:58 am | Report abuse |
    • spiffypants

      Iggy: They may have gotten 20 billion dollars out of them but wait. If they start to fail, Obama will be there for the rescue with a bailout from you and I.

      June 17, 2010 at 6:01 pm | Report abuse |
  3. Slickoil

    Getting closer and closer to the real flow rate of the oil. The actual amount of oil coming out of there is probably 200,000 barrels a day. Ok, I'm on the high side be 100 percent. We BP was on the low side by a factor of 60. Who is more accurate?

    June 16, 2010 at 10:33 pm | Report abuse |
  4. Joan

    How much did Union Carbide pay for the disaster in Bhopal? Oh, that's right NOTHING

    June 16, 2010 at 11:35 pm | Report abuse |
    • inFLA

      I am sick of people bringing up Bhopal as a way to excuse what is happening here. Bhopal was a crime, yes. But it didn't kill an entire small ocean – the Gulf. It didn't kill millions of innocent animals and cause mass extinctions. It didn't potentially poison nearly oceans, like the Caribbean and the Atlantic. There is no comparison. We are witnessing an armaggedon in the Gulf.

      June 17, 2010 at 6:41 am | Report abuse |
  5. Shistar

    Omg and here we go with the $$$.... Soon they'll start asking for $$$.

    June 17, 2010 at 12:16 am | Report abuse |
  6. city guy

    Unless the gas is separated from the oil at the well head, it will never be truly plugged (I dont care how many relief holes you drill). Once the gas hits the water, it expands and technically is super cooled. The hydrates and ice will continue to form in whatever containment device they place on the thing.
    The only real solution is a series of HUGE boxes along the ocean floor trapping the gas/oil mix, allowing it to expand and bleed off the gas without ripping the boxes from the ocean floor due to bouyancy, Without that, nothing (and I mean nothing) is going to stop that leak..

    June 17, 2010 at 12:47 am | Report abuse |
  7. jerry riordan

    what liars these oil people are. when they try to convince us why high prices are justified they tell us it is because of how little these oil wells produce. now they are doing the same thing but for an other motive.

    June 17, 2010 at 1:04 am | Report abuse |
  8. PlaneShaper

    I'm by no means an engineer specializing in this area, but with a math and physics background, I'll take a crack at an analysis of the increase in the estimate itself.

    Basically, as explained below, the numbers provided to the public form a pretty obvious mathematical pattern that can be described with a convergent infinite product. The result is a final estimate of 71,527 barrels per day. Almost exactly what Prof Wereley estimated.

    So, the initial oil spill estimate was provided as 1,000 barrels per day (bpd). We all know that to have been way...waaaaaay off. But the change in the spill estimate over time can give us some clues as to what we might be able to expect as the final estimate (whenever that happens).

    The first increase to the estimate raised it to 5,000 bpd, so 5 times the original value. The next estimate provided a range of 12,000-19,000 bpd, an approximate median for that would be 15,000 barrels, or 3 times the previous value (1,000*5*3).

    The next estimate doubled the newest to 20,000-40,000 bpd. The newest estimate (yesterday) rose that one up to 35,000-60,000 bpd, so another multiplier of about 1.5.

    This gives us an effective median value of (1,000*5*3*2*1.5)bpd to get us to the current estimate. A pattern quickly emerges from the multiplier. Subtract 1 from each of those and you'll have [4,2,1,0.5], a nice set of decreasing powers of 2. So, let's set this up:

    1,000bpd * product[1+2^(-n)], n=(-2)...(inf)

    The result of that covergence is ~71.5269.

    That gives us a median value of 71,527 bpd for the final estimate, assuming continuing the current trend of re-estimating the numbers. Since the lower limit for the estimate tends to rise slightly higher than the upper (about a sixth above the calculated value produced by formala), I'd say a final estimated range of:

    55,000-95,000bpd is what to expect.

    Again, not an analysis of the flow itself, but an analysis of the analysis of the flow.

    June 17, 2010 at 1:58 am | Report abuse |
    • nanobot

      OMG....how logical. You must be good at the stock market.

      June 17, 2010 at 3:38 am | Report abuse |
    • russ

      certainly intersting

      June 17, 2010 at 12:02 pm | Report abuse |
  9. dj

    It's too bad John Wayne wasn't with us. He capped a lot of wells in his time and he sure wouldn't have any patience with this one. He would be on the sea bed with his gloves on hours after the blowout!

    June 17, 2010 at 3:25 am | Report abuse |
  10. No Oysters

    It's called "lying". A word that is seldom used in politics and business, mainly because they lie for each other.

    June 17, 2010 at 3:33 am | Report abuse |
  11. Anth

    what is the comparison ratio to : what is flowing in the ocean and what is being siphoned out of the ocean ?

    June 17, 2010 at 3:59 am | Report abuse |
    • nanobot

      Don't know. The best way to tell is compare the video when they put the cap on before it was actually sucking and now, when they are sucking. Maybe 20% is being sucked and collected now? I don't think BP has an archive of the video so you CAN compare, but it's safe to say there hasn't been much reduction yet. I'm hopeful that the direct flow out from the BOP will be substantial reduction in oil spillage very soon.

      June 17, 2010 at 4:09 am | Report abuse |
    • nanobot

      BP has announced they are now sucking 12k barrels in 12 hours using the BOP direct connect with the cap. In 24 hr that would be 1 million gallons per day. However, if you look at the video you can barely perceive any difference in the billowing when the sucking wen from 15k to 24k barrels (630,000 gal to 1 mil gal) and not a significant difference from the billowing before the cap was sucking anything at all. Clearly, with 1 milion being removed now the total has got to be at least 3 million per day. That extrapolates to the worst oil spill in history in the world.

      June 17, 2010 at 8:02 pm | Report abuse |
  12. DJ

    When I look at that blowout preventer and think of it's size I can't help but think, where's the backup valve? Shouldn't these things have some sort of manual valve that can be cranked by a robot to shut it down?

    I realize that doesn't help the current situation, but what where they thinking when they designed this thing?

    June 17, 2010 at 5:17 am | Report abuse |
  13. 3seven0

    Read June 12th at the bottom of the page. Looks they have more problems than they know what to do with and Washington knows it. No wonder they're pushing for the relief wells.


    June 17, 2010 at 8:26 am | Report abuse |
  14. thatguy212

    This has happened in the past when Russia tried tapping into this same vein that goes half the way around the world. They tried it four times and each time that had to use nukes to shut it down because it is the mother load of all oil reservoirs. They warned bp not to drill it because the pressure is to great to contain but bp went ahead and tried anyway. The only way to stop this is by setting off nukes .

    June 17, 2010 at 9:56 am | Report abuse |
    • russ

      please pointto your source for that information...never heard of this

      June 17, 2010 at 12:04 pm | Report abuse |
  15. Beam Me Up Scotty

    Is it possible that the gusher is actually getting worse over time?

    June 17, 2010 at 10:05 am | Report abuse |
    • ar

      absolutely... it will get bigger and bigger until the entire oil reserve is depleted (about 2 BILLION barrels), unless it can be shut down – a tricky and uncertain procedure consisting of quickly squirting mud into the well. If it can't be stopped, it could spew an Exxon Valdez worth of oil every week for a more than a decade. These wells are more dangerous than a nuclear reactor, and should be treated as such as far a regulation is concerned.

      June 17, 2010 at 8:56 pm | Report abuse |
1 2 3 4 5 6