The total amount of fluid expected to be produced from a given reservoir before the end of economic fluid production.

It can be applied to any fluid production: water, oil or gas. 

In Petroleum Upstream it usually means either Estimated Ultimate Oil Recovery (EUOR) or  Estimated Ultimate Gas Recovery (EUGR).

In both cases it refers to the maximum recoverable volume of Hydrocarbon Reserves (HCR).

The percentage of Estimated Ultimate Recovery (EUR) with respect to the total Surface Tank Hydrocarbon Initial In Place (STHCIIP) is called Estimated Ultimate Recovery Factor (EURF).

Unlike Hydrocarbon Initial In Place (HCIIP) which is a geological category, the concept of Estimated Ultimate Recovery (EUR) depends on FDP and Petroleum Production specifics (recovery method, recovery duration, surface logistics, market conditions and economics). 

See Also

Petroleum Industry / Upstream / Subsurface E&P Disciplines / Petroleum Geology /  Petroleum Reservoir / Petroleum Reservoir Fluids / Hydrocarbon Initial In Place (HCIIP)

[ Estimated Ultimate Oil Recovery (EUOR) ] [ Estimated Ultimate Gas Recovery (EUGR) ] 

[ Estimated Ultimate Recovery Factor (EURF) ]