Venezuela as long historical ties with Iran; the two were the principal founders of OPEC.
Chavez has had a target on his back for a long time - perhaps actively so since 1999 when he dared, despite US protests, to cross into Iraq to meet with Hussein. Objective - rebuilding OPEC and bringing it back to relevance.
At the time OPEC was drifting towards obscurity; infighting among members was assuring that. Such infighting worked for the US too, of course.
Chavez visited all the major movers and eventually had the leaders of these countries (or their proxies for those who could not safely travel) come to the first head of state meeting of OPEC leaders in a quarter century... in Venezuela.
As we well know since then, OPEC returned to relevance.
Not often talked about with respect to either Iran or Venezuela is that since the 1950's conservation of resources has been a part of their planning culture. When thinking about Iran and its nuclear power ambitions, this explains part of their drive to generate more electric power via nuclear energy rather than from fossil fuels.
I certainly am concerned that the US will try to increasingly draw linkage between what is happening in Iran and Venezuela. Its unlikely that the US could achieve a complete embargo on Iran but if they intend to do that, certainly the nuclear issue is the one to hoist up the flag pole.
A decree that an oil export ban to the US from other states - without naming Venezuela - would be considered an act of war or aggression against the US, during any Iranian action, is rather what I expect.
One thing is certain - if Chavez works in sympathy with Iran, it is highly unlikely that he will do so on his own without at least trying to get other OPEC nations to join.
Bicycling will again be popular if any of this comes to pass.