It could easily become part of Iraq. None of the states of the Arabian peninsula have a military which can defend its own borders and Obama won't commit troops to defend oil after spending six years championing "no blood for oil".
I always see the worst side of things, and I would avoid major cities for a while. Once we're fully withdrawn from Iraq, the country will fall to jihadists and they will likely be expansionist. They'll be less harsh subjugating minor cities and suburbs.