Oil getting in to spark plug well?

[USMC5811]

So while changing my spark plugs today I noticed that the coil pack on the right rear (I believe its cylinder 5) had a very small amount of dried up oil on it. Upon further investigation i noticed that I could see oil between the valve cover and the spark plug well. Once i got the spark plug out I noticed a very small amount of oil accumulated at the bottom near the threads, however the spark plug itself had absolutely no oil on it. The car runs and drives perfectly fine as it should, I was just wondering if this was a common problem or even a problem at all? I thought that there were seal to keep the oil out so I figured maybe that one went bad, but then I read that the entire valve cover would need to be replaced, which I'm guessing is a huge PITA. Can anyone help me out on this one? I'm debating just ignoring it until a problem presents itself just because there's nothing wrong as of now, but I'm not sure if this is a bigger issue than I think it is. Any and all advice is greatly appreciated! Thanks guys!

[M4point5]

Its caused by the spark plug tube seals...it will need attention sooner or later. Happens a lot on these Nissan V8s and unfortunately doing valve cover gaskets suck. Whether on a V6 or V8...happened on a QX4 we used to have and even though there seemed to be a ton of space under the hood, everything was crammed on top.

[EniGmA1987]

Doesnt that mean your valve cover gasket is either leaking or cracked? Which IMO is a common problem because I have had it happen to me 3 times, but that is cause I apparently "drive too hard"

[thomasm35]

I had the same problem with number 6 cyl when I changed the plugs at a 102K miles. I just replaced the plug and decided to do nothing. I figure there is no place for the oil to go and the worst thing that can happen is the plug can misfire if the oil in the spark plug tube reaches the top of the plug. I have driven about 9K since the plug change and had no problems - in another 10K I will look in the tube and see how much oil there is. You are right, changing the seal looks like big job - you have to remove a lot of stuff to take the valve cover off. I think this will be my last Infiniti!
I just did a road trip from Los Angeles to Kansas City and drove my wife's 2007 Lexus LS460 because I could cruise at 80mph at 2000rpm and get 30 mpg.