Yes, I know it's not technically just methane, but methane is its primary constituent.
"Fossil gas" is also probably a suitable term, but I like "fossil methane" because it gets that spooky chemical name benefit.
This is great. Reminds me of how in Alberta they call tar sand fields the "oil sands" because then it hides how filthy and dirty it really is and how much processing is needed to make it viable.