Reservoir EngineeringMaterial Balance
Cumulative Gas Production from Gas Expansion Formula
Cumulative Gas Production from Gas Expansion calculates cumulative gas production for material balance workflows in reservoir engineering.
How engineers use this formula
Use this formula when the listed inputs (G, B_gi, B_g) are known and the assumptions behind the cited material balance 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, G_p equals 333,333,333.333333 SCF.
GSCF
1000000000
B_gibbl/SCF
0.004
B_gbbl/SCF
0.006
Inputs
G
SCFOriginal Gas In Place
B_gi
bbl/SCFInitial Gas Formation Volume Factor
B_g
bbl/SCFGas Formation Volume Factor at Current Pressure
Outputs
G_p
SCF
Cumulative Gas Production
G
SCF
Original Gas In Place
B_gi
bbl/SCF
Initial Gas Formation Volume Factor
B_g
bbl/SCF
Gas Formation Volume Factor at Current Pressure
Source and review
reviewedPengTools Wiki. Gas Material Balance; Penn State PNG 301 gas material-balance derivation.
Source