Planet Money had a wonderful series of episodes where they did exactly this a few years ago.
https://www.npr.org/sections/money/2016/08/26/491342091/plan...
They traced the path of their barrel from purchase, to production, to refining, to the sale of the various hydrocarbon products.
It's a great listen.
Makes me sad hearing this. Planet Money fell off so hard in the years after this
Did they pay extra for the barrel itself? Surely that steel doesn't come for free.