It's usually hard to see minor oil burning - rev up the engine with the exhaust venting into an enclosed space for a short time and see if you can see blue smoke accumulate. Do this so you are outside and the exhaust blows inside -- that way you won't kill yourself by carbon monoxide poisioning, no joke.
If not, most likely is a rear main seal leak or cam seal leak since you don't see dripping with the car is parked. This you can spot pretty easily visually from underneath if the car is on a lift.