That would be 1 way to spice up the oil demand. But for defending, maybe use 1/2 of what each unit requires for attacking.

ouch lol

I think if you used the search function, you would see this has been suggested before, and in fact in that thread there is quite a bit of discussion, because of how easily abused this could be if you always defend with all units. aka, repeatedly 1 troop SSing would use all the defender's oil etc.

you could adjust the oil used to the size of the attack. Still abusable, but less of a catastrophic problem.

what if I have oil to protect myself of 3 attacks, and someone does 9?

he gets 6 easy breaks?, been suggested, and would create more problems rather than fix them.

1st raid oil storages and then kill country.