While they have been under heavy sanctions, they have largely gotten around this, for example by trading with China (who have just said they will not abide by our "unilateral sanctions"). So their oil has still been going to service global needs, and its lack will still have an effect (as will the missing Russian oil products).

Oddly, since the Iranians (and Russians) have been selling their oil products at a discount, they were actually having the effect of holding down the price of petroleum prior to the war. No idea about how much in real terms, but...