High oil is a Petro Dollar policy.
Low oil is not...it contradicts Petro Dollar.
The petrodollar isn’t a policy, it’s an arrangment and the actual cost of oil is not really a function of the arrangment. Oil must be purchased with US federal reserve notes whether the cost of oil is high or low. The actual price is irrelevant as far as the arrangment is concerned. What is important from a western capitalist’s/banker’s persepctive is that foreign countries must maintain large reserves of US federal resere notes in order to purchase oil.