Fermenting 6 gallons in a 14 gallon conical, O2 issues?

The title pretty much says it all. Just wondering if I put about 6 gallons of wort into a 14 gallon conical if I should worry about O2 issues with the fermentation and finished beer.

My thoughts are that the surface area is about the same as a 6.5 gallon glass carboy as the diameter of the conical is 23 inches and the diameter of the carboy is 20.5 inches. I am talking the top of the wort, I am unsure of sides.

I guess I am wondering if the extra head space would present an issue? If so, could I purge the whole fermenter with CO2 before racking my finished wort into it?

Thanks in advance!

There shouldn't be an issue. CO2 is heavier than air, so there is effectively a blanket of CO2 on the surface of the wort. There's also enough CO2 produced to purge the vessel over the course of fermentation - there's a lot more than you might think.

In addition, you want oxygenation prior to pitching the yeast so no worries.

I routinely do 5.5-7 gallons in an almost 14 gallon vittles vault with no issues, I leave it in there for 3 weeks and have never had oxidation problems.

Thanks to all who posted. glad to hear others have tried and had success.