PetroCalcHubFree
Reservoir EngineeringMaterial Balance and Production

Hydrocarbon Pore Volume Occupied by Remaining Oil Formula

Vro=(NNp)BoV_{ro}=(N-N_p)B_o

Hydrocarbon Pore Volume Occupied by Remaining Oil calculates hydrocarbon pore volume occupied by remaining oil for material balance and production workflows in reservoir engineering.

Calculate

How engineers use this formula

Use this formula when the listed inputs (N, N_p, B_o) 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, V_ro equals 1,080,000 bbl.

NSTB

1000000

N_pSTB

100000

B_obbl/STB

1.2

Inputs

N

STB

Oil in Place

N_p

STB

Cumulative Oil Production

B_o

bbl/STB

Oil Formation Volume Factor

Outputs

V_ro

bbl

Hydrocarbon Pore Volume Occupied by Remaining Oil

N

STB

Oil in Place

N_p

STB

Cumulative Oil Production

B_o

bbl/STB

Oil Formation Volume Factor

Source and review

reviewed

Advanced Reservoir Engineering, Ahmed, T., McKinney, P. D. (2005)

Ahmed, T. and McKinney, P. D. 2005. Advanced Reservoir Engineering. Gulf Publishing of Elsevier, Chapter 4, Page 301.

Source

Related formulas and calculators

Average Permeability for Linear Flow in Layered Beds
Permeability
Average Permeability for Linear Flow - Series Beds
Permeability
Average Permeability for Parallel-Layered Systems
Permeability
Average Permeability in Radial Systems
Permeability
Klinkenberg Apparent Gas Permeability
Permeability
Jones-Owens Klinkenberg Slip Factor
Permeability