I am sure, that there is some coin which is correlating with the price of oil. Mostly with Synthetix ERC-20 tokens. They are backed up by SNX tokens so you are extremely safe and if the price of SNX tokens will lose, you still don't have to worry - they have correlation rate 800% so there is minimal chance to lose it.
How is SNX token safe ? No Erc token is safe at the moment not even the USDT (Tether).
To me I don't think that bitcoin will be used to purchase crude oil for now but I think it be possible in time to come because the way bitcoin is going at the moment in the next five years to come or more I think you can purchase crude oil with bitcoin.
Since that happens on the government level, bitcoin needs to be legally accepted for that to happen.