Venezuelan oil is kind of crappy. I would say the two biggest reasons for this are 1. Trump wanting migrants from Venezuela to stop and 2. Ending Venezuelan support for Cuba. Oil is definitely one of the reasons though.
It is heavy crude but it's what our refineries are set up to use. There was a very informative news report on this recently posted to youtube: https://www.youtube.com/watch?v=Pgwny1BiCYk
Apparently shale oil mostly comes out as light, so our own production doesn't feed our refineries and we've increasingly taken to importing heavy crude.
Maybe worth mentioning I posted this before seeing the news about Maduro being captured. No idea whether/how that might change the calculus.
Venezuelan oil is very heavy, but the US oil industry is literally designed to process this type. The US exports their sweet crude elsewhere because they can't process it.