Refers to all oil currently present in Petroleum Reservoir.
The volumetric value of OIP in NTP conditions is given by STOIP.
The changes in volume and structure of OIIP over time can be caused by production from a given petroleum reservoir or because of the hydrocarbons migration caused by production at offset hydrodynamically connected petroleum reservoirs.
See Also
Petroleum Industry / Upstream / Exploration / Booking Reserves
[ Hydrocarbon Initial In Place (HCIIP) ] [ Gas Initial In Place (GIIP) ]
[ Surface Tank Hydrocarbon Initial In Place (STHCIIP) ] [ Stock-Tank Oil Initial In-Place (STOIIP) ] [ Stock-Tank Gas Initial In-Place (STGIIP) ]