Yes the Canadian oil sands have the reserves in the ground but an oil sands plant takes years to build and we are not even talking take away capacity.
You would be surprised how quickly things happen during wartime. Most of the several thousand mile long pipelines in the US were initially built during WW2 with government review of concept to in service times of 2 years or less. They've all been massively upgraded since. Once the right of way is acquired, the sky is the limit for capacity as long as people are willing to spend money to lay down even more pipe.