Oil in place is a term referring to the total hydrocarbon content of an oil reservoir and is often abbreviated STOOIP, which stands for Stock Tank Original Oil In Place. In this case, stock tank refers to the storage vessel containing the oil after production. An oil reservoir is a subsurface body of rock having sufficient porosity and permeability to store and transmit fluids. ... Oil in place is a term referring to the total hydrocarbon content of an oil reservoir and is often abbreviated STOOIP, which stands for In this case, stock tank refers to the storage vessel containing the oil after production. ...

Calculating STOOIP

Accurate calculation of the value of STOOIP requires knowledge of:

• volume of rock containing oil (reservoir volume, usually in acre-feet)
• percentage porosity of the rock in the reservoir
• percentage water content of that porosity
• amount of expansion that the oil undergoes when brought to the earth's surface

and is achieved using the formula

STOOIP = (7758 * RV * POR * (1 − Sw)) / Boi

where

• RV = Rock volume (acre-feet)
• POR = Fluid-filled porosity of the rock (percentage)
• Sw = Water-filled portion of this porosity (percentage)
• Boi = Formation volume factor (factor for the change in volume between reservoir and surface conditions)

The constant 7758 converts acre-feet to stock tank barrels. An acre of reservoir 1 foot thick contains 7758 barrels of oil.