Exactly who are these "U.S. oil barons" who would benefit dianavan?

At present there are NO American oil companies present in Iraq.

I am at least encouraged that we have established the fact that the Government of Iraq has not mentioned any intention of pulling out of OPEC. The US has got no influence whatsoever on whether Iraq is a member of OPEC or not, so the "what if" conjecture is a pointless exercise.

But to return to one point of conjecture in your post relating to the U.S. oil barons:

"..the U.S. oil barons would benefit by not being restricted by OPEC regulations."

Now how do they benefit? By increasing production (if they could) and lowering the price per barrel? Hardly in their interests I would say.

In Iraq ALL pipeline transportation systems are OWNED by the State run Oil Company. Not one drop of Iraqi oil can go anywhere without their approval, they control the flow, not "the U.S. oil barons" (even if they were present in Iraq, which they are not), or the executives of the French, Russian and Chinese oil companies who are operating in Iraq.