Where can I trade Bitcoins for Crude oil?
Nowhere. Even Europeans have to buy oil inUS$ due to the Bretton Woods Treaty. The Russians & Chinese would buy/sell oil in gold or their own currencies in a heartbeat if that wouldn't get them sideways with the US fed.
The Chinese and Russian DO buy it with their own currencies now, they signed a treaty a few months back that took that U.S. out as the reserve currency. That's one of the major reasons for the U.S. going to so many wars lately, they're trying to keep there position of power over the world, but since up to 50% of earth no longer accepts U.S. currencies (including large parts of the U.S.) their already toast.
Even that only applies to direct trade of crude between Russia and China. Which, admittedly, is a pretty large market; but by itself is not a game-changing event.