The only foundation that I have found great for oily skin is Make Up Forever Mat-Velvet foundation. I get oily in the T-Zone, around the nose and chin. Its kind of thick but that's how it keeps your face matte throughout the day. It says water-resistant but I don't think so. Before applying the foundation, I use NYX Shine Killer Primer. I also use ELF's High Definition Translucent Powder to set the foundation, using a little more around where I get oiliest. I use a large duo-fibre brush to get rid of any excess that makes my face look powdery. Then I set my face with Urban Decay's All Nighter Spray. If you're on a budget, ELF also has a setting spray too. For the last couple years I have had trouble finding a way to prevent being oily throughout the day but these products actually make me satisfied. I don't get oily later on in the day and it looks like I just applied my make-up. But remember, being a little oily is okay and it makes your skin look natural. Too matte can make your skin look cakey. Hope this helps.

Have you been to a store like Sephora or another department store where they will give you samples? I've had the best luck figuring out the right foundations, concealers and BB creams by getting samples at Sephora and testing them out for a day or two. I actually reviewed concealers and BB Creams on my blog via samples at Sephora. I personally loved the Tarte BB cream for all-over light coverage (I have combo oily skin), but its not super heavy like a foundation. Definitely get some free samples! Also, some drug stores (Target) allow you to return makeup even if you've used it!