What OPEC is Up Against
Frankly, the demand side even looks worse. The self drive car, the self drive heavy haul truck will both drive down fuel used on a per passenger mile basis.
This will happen for a wide variety of reasons, the Uber hail ride, and the share ride capability all will pressure prices lower since they are likely to increase fuel economy. Smaller engines are highly likely to become standard, one does not care about engine size if one is not driving, so engines are likely to become much smaller. Fewer accidents, will allow lighter vehicles, also reducing fuel use per passenger mile.
All of these things and myriad more are likely to decrease fuel per passenger mile, and petroleum is primarily an automotive fuel, and lubricant.
Further, auto fleets, and truck fleets are switching to natural gas, or other fuels, all which will lower the need for petroleum.
There is also the promise, potentially hollow, of the electric car. If this works out, it will also reduce the need for petroleum.
Looking holistically is only worse.