And that in turn wuld have a potentially large influence on figuring out a peak, wouldn't it?

If 84 mbd is produced, with that 20:1 EROEI, you lose 4.2 mbd every day, so you have net production of 79.8 mbd. That is quite a difference.

And it would be less important if EROEI stayed the same, but it's getting worse all the time, so you lose ever more, and the numbers reflect reality ever less.

I understand that it would be hard to model, but still feel it's too easily neglected.

You biofuel comment is valid. I guess it would be too much of a stretch to look at natural gas use, like in the tar sands?! It may not be C+C (+NGL), but is sure is a waste of energy. Isn't it more appropriate to count these things in some kind of "energy" form, like calories, or joules, or......?

The 'triple-net' is far far lower than 20:1, when you include indirect costs (hiways, insurance, food transport, etc) and environmental externalities. So as energy becomes more difficult to access, the % allocated to energy sector, wide boundaries and all will increase. How much of the 85 mbpd is required to procure the 85mpbd now is an interesting, important and near impossible question to answer.