So, basically, Canada is Rogered, as it will take years to build more pipelines.

I mean, only a little. Canada exports about 4.2 million barrels per day to the U.S. Venezuela only has about 0.6-0.7 mbpd of production that could possibly go to the U.S. Canada's got about 0.4 mbpd of unallocated capacity in their new pipeline, which was expected to be absorbed over the next few years - some of that absorption might get drawn forward, though there might be some issues with the blends. So the delta is only 0.2-0.3 mbpd that might have some issues for a few years.

Yes, it takes years to build more pipelines. But it will take more years for Venezuela's oil production to expand from current levels.

Plus, there's the other escape valve - Canada could still just pipe to the Gulf, and then export their oil from there as crude rather than being refined. It would be a little wasteful to have Venezuela ship their oil north to the Gulf, while Canada ships their oil south from the Gulf on to China, rather than just having Venezuela ship to China, but that's what would probably happen as the fungible oil sloshes around the distribution system.