I took the article’s barrels, multiplied by 55, and rounded up on the grounds that one ought to round against one’s self when arguing (probably about a 10% difference due to rounding).
I have no idea what your next to last sentence means, but would be very interested in learning. I also understand that your last sentence is meant to shed light on the previous sentence, but I don’t get it—my guess is that I’m off three orders of magnitude due to something I don’t understand.
Just to prove myself as pedantic, an oil barrel is 42 gallons not 55.
I think what he meant was that 3.2 billion barrels of oil is the amount of oil in an entire major oil field. For example, 4 billion barrels of oil is the estimated total recoverable amount of oil in the Bakken Shale formation (and that’s actually the upper-end estimate of 10%).
Depends on which barrels!
From Wiki; “Although crude oil is sometimes shipped in 55-US-gallon drums, the measurement of oil in barrels is based on the whiskey barrels of the 1870s which measured 42 US gallons (35 imp gal; 159 L). The measure of 42 US or wine gallons, corresponds to a wine tierce”