It'll certainly be interesting. Canada does not have anywhere close to the export capacity to stop selling oil into the USA. I suspect if a 25% tariff happens that would push up US oil prices compared to world prices, although maybe not by the full amount.
Canada would be screwed, because quite a bit of production can't really shut in (it wrecks it) and so needs to keep going and becomes a price taker. But production would drop, exports to the coast would increase, and you'd see crude-by-rail to eastern Canada.
Higher domestic US oil prices than world oil prices would spur US drilling, but would also harm US refining, which is an export industry.