May have subsequently changed, but when I worked in that region:
-the professionals were invariably western "ex-pats";
-the clerical/technical/merchant support was primarily from India and Pakistan (often the under-compensated "infra-structure" that allowed the system to work), and
-the artisan/skilled craftsmen were sourced based on the required level of skill
-crane and heavy equipment operators were usually "ex-pats,"
-higher-skilled crafts like welders/electricians/instrument techs/etc. from places like the Philippines, India, Pakistan, etc. and
-lesser skilled crafts like masons, pipe-fitters, laborers, etc from regional Muslim countries like Egypt, Iraq, Jordan and even Sudan, Somalia, Ethiopia, etc.
-as a sop to the conscience of the sheiks, there were local "guards" -- but they either slept or prayed all day.
TL/DR: very few displaced indigenous workers in oil kingdoms. To stay in power, the rulers in that region need funds for the life-styles of the natives who do not work.