I don't think of tea has having oil, I think of it as tannic and a bit astringent. What are you using it for, and how much? That would make a difference, I think!
Now I know I am not the only one. I have been thinking about a Green Tea Pale Ale for months. I think I am going to just experiment with it and see what happens. I want just enough to give it a hint of green tea flavor.
I did a taste test by dumping a couple of ounces of green tea into 12oz of a pale ale. The bitterness was off the charts in my opinion. Granted the taste might be a bit different in fermented wort. Explains why everyone who has done it only uses a couple of teabags or so. My original plan was a gallon of green tea in a five gallon batch, I think I'd be making a $40 dollar mistake on that one.