Please don't run it for long like that, at all..
My parents 1.8T passat was making a similar noise and we thought nothing of it, like perhaps something rubbing.
It turned out to be the oil pump, it was completely fried/burnt out and died on me while driving, completely lost oil pressure luckily the warning came up and I was able to stop where I was.
I had a similar issue with the Passat, I would hear it below around 2000 and above that I couldn't hear it or the engine was just louder, not sure.
Remember the oil pump on those motors runs on the chains inside of the engine.
I've uploaded a video for you and others to compare it to just to be sure.
http://youtu.be/c3850njI2-M