When billions of barrels of oil are extracted from artic will hole left be filled with melted ice cap?

rhs is correct (as well as Tomcat). The oil is contained within the groundwater and flows upward to some sort of geologic trap. It is a very small percentage of the surrounding fluids. If you extract billions of barrels, I would suspect that it would subside a little but it would also get replaced by the surrounding fluids. One cubic meter is actually 6 barrels so 6 billion barrels would be a cube that has 1000 meter sides just to give it some scale.

good old mother earth gets around pretty good for a girl her age and with all the action she gets that old hole will fill up really fast as long as you think in terms of geological cycles maybe a couple thousand years or a millon years what ever her cycle is.

no it wouldn't be noticed

There are wells drilled to 40,000 feet down-- nothing bad is ever going to happen-- as proved by a century of drilling with many wells already capped for decades.

you should worry more about this http://www.livescience.com/environment/080724-black-smokers.html

apparantly mining in the artic is banned for a further 50 yrs

LOL!! that a good question

Not even, close, oil is on the way out, if this supply was used it would last ~2 years at our current rates of use.