Cumulative Oil Production – Undersaturated Oil Reservoirs Formula
Cumulative Oil Production – Undersaturated Oil Reservoirs calculates cumulative oil production for pvt and rock-fluid properties workflows in reservoir engineering.
How engineers use this formula
Use this formula when the listed inputs (N, c_e, Bo, Boi, dP) are known and the assumptions behind the cited pvt and rock-fluid properties relationship match the engineering case being checked.
Assumptions
- Input values are representative for the well, reservoir, fluid, or equipment case being evaluated.
- The declared units match the field-unit constants used in the formula.
- The cited formula applies to the selected petroleum engineering workflow.
Limitations
- The calculation does not replace a full engineering model or operating procedure.
- Accuracy depends on the source correlation, assumptions, input quality, and unit consistency.
Common mistakes
- Mixing unit systems without converting the inputs.
- Using default example values as field recommendations.
- Applying the formula outside the source assumptions.
Default example
Using the default inputs, Np equals 5,454.545455 STB.
1000000
5e-6
1.1
1.2
1000
Inputs
N
STBInitial Oil-in-Place
c_e
1/psiEffective Compressibility
Bo
bbl/STBOil Formation Volume Factor at Assumed Reservoir Pressure
Boi
bbl/STBOil Formation Volume Factor at Initial Reservoir Pressure
dP
psiPressure Differential
Outputs
Np
Cumulative Oil Production
N
Initial Oil-in-Place (rearranged)
c_e
Effective Compressibility (rearranged)
Bo
Oil FVF at Current Pressure (rearranged)
Boi
Oil FVF at Initial Pressure (rearranged)
dP
Pressure Differential (rearranged)
Source and review
reviewedAhmed, T., McKinney, P.D. (2005). Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 5, Page: 333.
Source