> at what price per barrel does US oil fields get profitable?

$30 to 70 per barrel [1]. (Pretty much all production is profitable above $100/barrel.)

> they don't really need the Irani oil do they ?

Our refineries can't process our own crude. So we export crude and import refined products.

That said, yes, the oil exports do blunt the net effect of the blow. If pressure really rose, one could tax the excess profits to directly reduce gas prices.

[1] https://www.opxai.com/why-your-oilfield-will-fail-at-60-oil-...