Iran was the first to nationalize oil back in the early 50's. The rest of the mideast followed suit back in the mid-70's. I don't see U.S. involvement in the MidEast so much as an effort to privatize the oil industry over there, as it is to keep oil supplies stable and plentiful by trying to maintain friendly governments and work against unfriendly ones. I don't think reprivatization will occur - much like it did not occur when Kuwait was liberated.
Dates of nationalization of oil in the North African and Mid East region
Iran\t\t\t\t\t\t1950
Algeria\t\t\t\t\t\t1971
Iran\t\t\t\t\t\t1973
Libya\t\t\t\t\t\t1973-1974
Upper Gulf State\t\t\t\t1973-1974
Saudi Arabia\t\t\t\t\t1974-1976
Kuwait\t\t\t\t\t\t1975
Lower Gulf States\t\t\t\t1976-1980