Why not tarrif countries that buy from Venezuela as well.
Then you can have a monopoly on their heavy crude.
A comment was also made that the US doesn't need Canada's oil either.
Funny how that could be as US refineries aren't set up to make gas and diesel from US light crude.
The US doesn't have any heavy crude of its own.
Why do you think the US can have such cheap gas and diesel.
Canada, Mexico and Venezuela.

Food for thought.

https://www.google.com/search?q=how+much+of+us+heavy+crude+comes+from+venezuela&oq=how+much+of+us+heavy+crude+comes+from+venesu&gs_lcrp=EgZjaHJvbWUqBggCECEYFTIGCAAQRRg5MgkIARAhGAoYoAEyBggCECEYFdIBCjI4NTk0ajBqMjmoAgCwAgE&client=ms-android-samsung-rvo1&sourceid=chrome-mobile&ie=UTF-8