Partitions may also prove to be quite tricky, would be dividiing up the spoils of the crude oil exports between the three, assuming that their territories would not have an equal share of the wells.
I completely agree, particularly in terms of the oil reserves, as all three factions would want their share. Certainly Turkey does NOT want the Kurds establishing an independent state as this would cause all sorts of problems within Turkeys borders. An alternative to three completely independent states, would be the establishment of three autonomous "provinces" (sunni, shiite and kurd) with a loose, centralized federal government represented equally by all three groups to administer the oil industry and central bank, yet leave matters of defense, education, culture and religion entirely up to each individual province.
Regrettably, I think this is wishful thinking however. I believe the bad blood between these groups runs far too deep for any form of co-operative government to ever serve as a federal, unifying entity.