Based on context may mean either Estimated Ultimate Oil Recovery Factor (EUORF) or Estimated Ultimate Gas Recovery Factor (EUGRF)
The maximum expected volume of Petroleum Hydrocarbons to be recovered is called Estimated Ultimate Recovery (EUR).
See Also
Petroleum Industry / Upstream / Production / Subsurface Production / Estimated Ultimate Recovery (EUR)
[ Estimated Ultimate Oil Recovery (EUOR) ] [ Estimated Ultimate Gas Recovery (EUGR) ]