So capital costs range something in the neighbourhood of 55% to 30% depending on region, and (again regional) total costs looks something like ~$52 a barrel (highest cost regions - like north sea) to < $10 (middle east).

But once you've paid all that capital (and something like shale oil in the west has some of the highest relative capital costs) you're better to keep producing at anything north of opex, so maybe as low as $15-20 for a shale producer, or $5 for S.A.

This is all very estimated, but you start to see why they keep pumping.

Next add in things like transport and storage constraints, refinery capacity , etc and volumes range from zero to infinite regardless of prices.

source: we build modeling software for evaluation of these scenarios.