You do realize that oil is a global commodity and there are literally hundreds of sources for it around the world, and that one country buying from Canada will not affect the prices for other countries unilaterally?
If refineries in the US start talking larger deliveries of Canadian crude, and the product of that refinement is going to be exported, then yes it can increase oil prices in the US because it represents a loss of refinement capacity dedicated to the US market. Refineries having problems affecting capacity leading to regional fluctuations in oil prices is a very common news story.
I'm not saying that this is necessarily a bad thing - if it's good for the US refinery business and they may add capacity over time which might give us a bigger buffer to handle refinery problems. Or it might not, I'm not an oil futures analyst. But it could certainly raise US oil prices at least temporarily.