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It comprises Oil Initial In Place (OIIP) and Gas Initial In Place (GIIP).
The volumetric value of Hydrocarbon Initial In Place (HCIIP) in NTP conditions is given by STHCIIP:
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represented by two numbers: { Stock-Tank Oil Initial In-Place (STOIIP) , Stock-Tank Gas Initial In-Place (STGIIP) }
The changes in volume and structure of HCIIP 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.
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