When all the oil is finished in Arab countries, where will the Arab people go to live?

This is a scientific fact that petroleum is not forever. One day the stock beneath the earth will end. It is also a known fact that those oil-rich Muslim countries depend on their oil export. They do not have vast acres of fertile crop-fields to grow their own rice or wheat and other crops. How they will survive then? Which countries will accept them as refugees or a financial burden?