In a futures market you lock in the price you're going to sell it for in the future today. It doesn't actually matter what the market price is at the time.
Is this a contract to buy at that price, or an option to buy at that price?
In this case it's a contract that requires you to sell at a fixed price.
You buy oil today at $50, you stick it in storage, you sell it forward today for delivery in Feb 2016 at $55. You've locked in $5 bucks of margin. Your big risks are credit (i.e., the guy who agreed to pay you $55 is a no show when oil is $41, which is mitigated by nymex collateral requirements) and your oil storage blowing up (which is mitigated by insurance).