IIRC (going on distant memory)
Iraq oil had one of the cheapest 'lift' costs ($1)
Saudi oil was about $3
Balkan oil varied from $4.5 to $6 depending on if under water etc)
Cant recall North Sea oil but it may have been $6-8
Americas (ie Venezuela) was about $3-4
Alaskan oil got to about $8-12 depending on where

and so on.

Also published estimates that Iraq may actually now have greater total reserves that Saudia Arabia (something like 300 billion+ barrels)

The other staggering statistic was how much petrol (compared to all other countries) the US consumed each day of the year.

Then we got on to the topic of oil being the lifeblood of an industrial economy and as such if not protected could result in severe anemic reaction or death if cut off. Then onto what it takes by way of energy to be a super power & what proportions of the energy were required for military purposes & how that then becomes part of the lifeblood equation.

Doug M