We have introduced Oil rule la couple of years ago.
In our 1939 game rules, Axis players doesn’t have oil so they have to fight to get some because they’re going to face a penalty after the 7th round.
If you conquer a neutral oil territory you receive form the bank, twice of the value of the territory.
Ex: Saudi Arabia = 2 IPC so you’ll receive 4 IPC.
When you invade an ennemy oil territory, the player must give you twice of the value of the territory. Ex: Egypt = 2 so UK player must pay 4 IPC.