Refers to all oil initially present in Petroleum Reservoir before the anthropogenic invasion.
The volumetric value of OIIP in NTP conditions is given by STOIIP.
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 / Subsurface E&P Disciplines / Petroleum Geology / Petroleum Reservoir
[ 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) ]