Hi arizona21. I recommend the Dr. Brandt vacuum cleaner as your foundation primer and also treatment to help reduce the appearance of pores and unclog any impurities. This treatment doubles as a foundation primer and preps your skin for a smooth surface to apply your foundation.
I've gone through about a million primers and found that the mattifying ones tend to really suck a lot of the time- they make your makeup look gross and flaky. My absolute fave is Too Faced Primed and Poreless- it's amazing, makes makeup look way better, won't make you oily, and definitely minimizes pores. It's at least worth a try.
If you have severe oil problems you could also try a setting spray like Urban Decay's De-Slick.