Be prepared for a 2nd interview in Doha.For 2 days you will be interviewed both technically and by HR. Also you will undergo a thorough medical exam- if you have symtoms of diabetes, BP OR irregular heart beat forget your dream of joining QatarGas. They are very sensetive on medical.

As for phone interview it will be basically be by HOD you will be joining.

By the way which department are you interested in?