Self levelling compond on an oily floor?
If you want a well-performing coating, you must do surface preparation according to instructions. 

There aren't really any shortcuts around that. Oil is a contaminant that will fail almost any coating, and most definitely a water-based coating.  

If you're new to surface preparation, I'm sorry if it throws a monkeywrench into what you hoped would be an easy project.  I realize the temptation to shortcut. But it will give a very unsatisfactory result, and an even bigger mess to clean up.