It has been amply demonstrated that it is impossible for an invader to secure oil production (check out Iraq now and the Nazi oil situation during WW2). The simple reality is oil production infrastructure is insanely easy to destroy and very costly (time, money and material) to rebuild. Granted, if an invader is willing to spend enough resources, it may be able to get some production on-line for a while, but not a lot. As for the US trying to keep China from the oil, it can't happen because it is too easy to divert the oil between the ME and the US. The Nazi during WW2 were especially brutal and they still could not stop the oil sabotage. So the oil producers will have great political power in the near future and because the US is so hopelessly dependent on oil it will eventually have to give in to any demands the oil producers make even if it means throwing Israel under the bus after stuffing dynamite in their pockets to make sure things go really bad.
Saudi FM: We hope Iran uses sanction relief for development, not nefarious activities (Reuters)
from the article: London's burning for Dichter