The five major Venezuelan Orinoco heavy oil projects back in the 1990s were all U.S. and European companies. They used U.S., Canadian and European technology.
The process of upgrading extra-heavy, almost solid oil into lighter oil was all built by the super-majors, mostly from the U.S. Some of those companies, like Repsol from Spain, seem willing to go back. Others, like Exxon, have said they're not going to go back. It's still too risky.