Cumulative Oil Production in Undersaturated Oil Reservoirs Formula
Cumulative Oil Production in Undersaturated Oil Reservoirs calculates cumulative oil production for material balance and production workflows in reservoir engineering.
How engineers use this formula
Use this formula when the listed inputs (N, c_e, B_o, B_oi, DeltaP) are known and the assumptions behind the cited material balance and production 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, N_p equals 14,400 STB.
1000000
0.000015
1.2
1.25
1000
Inputs
N
STBInitial Oil in Place
c_e
1/psiEffective Compressibility
B_o
bbl/STBOil Formation Volume Factor at Assumed Reservoir Pressure
B_oi
bbl/STBOil Formation Volume Factor at Initial Reservoir Pressure
DeltaP
psiPressure Decline
Outputs
N_p
Cumulative Oil Production
N
Initial Oil in Place
c_e
Effective Compressibility
B_o
Oil Formation Volume Factor at Assumed Reservoir Pressure
B_oi
Oil Formation Volume Factor at Initial Reservoir Pressure
DeltaP
Pressure Decline
Source and review
reviewedAdvanced Reservoir Engineering, Ahmed, T., McKinney, P.D. (2005)
Ahmed, T. and McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter 5, Page 333.
Source