If those are pieces of the chain tensioner pad in the sump then do NOT start that engine again until it's fixed
If the pad breaks up completely its bye bye engine as the inlet valves will hit the pistons.
I'll go and find you the info, and also a thread where I show the job. You need two people to do it with the engine in the car - one to hold the cam, and one to put the tensioner back in.
Essential tools are a good quality T30 torx bit, a small torque wrench which can do 5Nm, and the camshaft locking tools, and of course the tensioner tool which usually comes with the tensioner pads. You have to take the cam sprocket off bank 2 to do it, but you can leave the exhaust cams in place.
Edit - this post here has most of the info you need plus a video of the job on the V6:
http://forum.a8parts.co.uk/showpost....0&postcount=73
This is obviously with the engine out where it's much easier, particularly since the engine can be rotated so the head is level. With the head level its possible to do it single-handed, but with the engine in the car and the heads at 45* you need the second person to hold the cam.
Factory procedure shortly...