Normally 'twice' with cleansers. its recommended no more than twice!
but u can wash your face with water as many times as u want!
doesnt matter if u have oily skin or dry skin, it works the same.
i wouldn't wash my face more than twice with cleanser each day, and usually once in the morning and once before i go to bed. and during the day, i could always wash my face with water only to refresh myself.
u could buy some skincare especially for oily skin, (anti-shine lotion etc etc). that should also help!