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Reservoir EngineeringMaterial Balance and Production

Pore Volume Occupied by Injected Gas and Water Formula

Vt=WINJBw+GINJBGINJV_t=W_{INJ}B_w+G_{INJ}B_{GINJ}

Pore Volume Occupied by Injected Gas and Water calculates total pore volume occupied by injected fluids for material balance and production workflows in reservoir engineering.

Calculate

How engineers use this formula

Use this formula when the listed inputs (W_INJ, B_w, G_INJ, B_GINJ) 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_t equals 302,000 bbl.

W_INJSTB

100000

B_wbbl/STB

1.02

G_INJSCF

50000000

B_GINJbbl/SCF

0.004

Inputs

W_INJ

STB

Cumulative Water Injected

B_w

bbl/STB

Water Formation Volume Factor

G_INJ

SCF

Cumulative Gas Injected

B_GINJ

bbl/SCF

Injected Gas Formation Volume Factor

Outputs

V_t

bbl

Total Pore Volume Occupied by Injected Fluids

W_INJ

STB

Cumulative Water Injected

B_w

bbl/STB

Water Formation Volume Factor

G_INJ

SCF

Cumulative Gas Injected

B_GINJ

bbl/SCF

Injected Gas 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 302.

Source

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