How much oil is in the leaking BP well?

Answer 1

Sometimes simple questions do not have simple answers. It is sufficient to say that the estimates have a large range, and are subject to change. My comments are valid for June 11, 2010 only.

Right now, BP is capturing oil coming out of the well using the LMRP. They indicated that it is capturing about 15,000 thousand barrels of oil per day (15 MB/D).

The US Geological Survey (Marcia McNutt, task force leader) was initially assigned responsibility to identify rates. The rate question is now being addressed by three teams- See related link.

The Plume Modeling Group estimates as of June 10, 2010, the oil coming out of the riser prior to the use of the insertion tube is 25 to 30 MB/D, but then give an outside range of 20 to 40 MB/D. This is not the current rate, but what might have been flowing nearly a month ago.

Unfortunately, this isn't the rate coming out now, because they cut the marine riser in preparation for the LMRP. Everyone agrees that this should increase the rate, the the experts have given an opinion on how much this should increase the estimates.

Some of the oil coming to the surface is also being loss by evaporation, skimming and controlled burns. The experts have not yet given an opinion on how much this should decrease the estimates.

However, if we ignore the increase and all the decreases except for BP's estimate of what is captured by the LMRP, an estimate of the current spill rate using the outer range numbers is 5 to 25 MB/D. This can be converted to millions of gallons by multiplying the numbers by 0.042, yielding 0.21 to 1.05 million gpd.

Remember this does not include (1) increase due to cutting of riser and (2) evaporation, burning and skimming decreases. Using the lower range of estimates, the claim that this is the largest accidental oil spill in the US is correct, and has far surpassed the volumes spilled by the Exxon-Valdez. Also, I note that in many of the largest spills, recovered oil was nominal, so just the total spilled (from the well or tanker) was reported. In this case, the reductions as mentioned above are significant.

See link.

Answer 2

Sometimes a short question doesn't mean a short answer.

The question of how much oil was flowing from the well during the period that the well was open to flow and how much in total was spilled, have been analyzed by a number of technical groups.

The well flowed from April 20, 2010 to July 15, 2010 a period of 87 days.

A Technical Task Force of experts reached a consensus estimate of a total flow from the well was 4.9 million barrels. A barrel of oil equals 42 gallons, so this is the same as 206 million gallons.

There is no one reliable method to estimate oil rates from an underwater well that is flowing both gas and oil. This causes inaccurate estimates. Some estimates were made by examining the flow of oil as it came from the broken riser as video taped by remotely operated vehicles. Other estimates were based on the observed spill area (area where a sheen or oil reflection could be observed).

But a significant part of the spilled oil was picked up by skimmers, burned or evaporated. Much of the remaining oil will be slowly dispersed by wave and wind action, then decomposed by bacteria.

So, if the 4.9 million barrel estimate is correct, then the remaining oil has to be some number less than this estimate. So, the best answer I can give you is the oil still in the Gulf of Mexico is likely to be considerably less than 4.9 million.

I think that the letter from BP is important. They give reasons why the task force number is not well substantiated and lacks calculation details.

See related links.