If you are really, really oily, and suffer from oxidization, I would not use a moisturizer or a primer under the foundation. I would take a dry cloth and blot away all of the oil. Or you can use Milk of Magnesia as a primer.
When applying concealer, make sure that you are blending it out correctly. Try using a beauty blending sponge. Once you do that, take some translucent powder and apply it to the area(s) where you put your concealer. This will help to keep your concealer in place.
Once you have done the above, add the foundation. You can try using a cream foundation (which is good for all skin types). Once you have done put the foundation on your face, I would use a buffing brush to push the product into the skin for a smooth finish. Then use the translucent powder all over your face. Take an all over face brush and sweep the remaining product away
Best foundations for oily skin:
Revlon Colorstay Foundation - Dries to a matte finish. Must be fast with blending as this product dries very fast
Makeup Atelier Paris Waterproof Foundation
Makeup Atelier Paris Gel Foundation - Both foundations are great for oily skin. Beware, once you get them on, they are very hard to get off. You must use a very good makeup remover.
Hourglass immaculate Powder Foundation - Starts off as a liquid and dries to a powder
MAQPRO Fard Foundation - Wax foundation that is waterproof. You will need to use a translucent powder, but once you do you will have flawless coverage.