Short term - I do believe we cannot go under 50$/barrel. Shale will collapse and the price will be brought up very quickly.
Long term - there is a strong and we are just about to begin wave 3.
Wave 1: Demand grows, supply grows.
Wave 3: Demand grows, supply stagnates.
Wave 5: Demand slows down, so as supply.
ABC - the Oil age is over, so as once the Stone age.