When you have oily skin, it is generally because of a lack of hydration in the layers of the skin. This causes your skin's sebaceous glands to produce more oil to balance out your moisture levels. Excess sebum can cause oily skin as well as clogged pores.
By using an oil, your skin will sense that moisture levels are more normalized and not produce as much sebum, bringing you back to equilibrium. Yay! :)
Also, fine oils penetrate the skin deeper. So if you have oily skin, fine oils can penetrate into the skin and deliver skin-enriching nutrients.
So your chances of having great looking skin, glowing, in fact, are greatly increased!