Cumulative Gas Production – Tarner’s Method Calculator
Enter the required inputs, confirm the units, and run the calculator to solve Gp. Review the formula source and assumptions before using the result in engineering work.
Calculation context and source notes
Cumulative Gas Production – Tarner’s Method calculates cumulative gas production for material balance and production workflows in reservoir engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Use this formula when the listed inputs (N, Rsi, Rs, Boi, Bo, Bg, Np) are known and the assumptions behind the cited material balance and production relationship match the engineering case being checked.
Solves for
Gp (SCF)
Best next page
Formula, variables, and sourceFormula, variables, and default calculation
Reproducible default result
With the default values shown below, the calculation returns Gp = 416,000,000 SCF. Defaults demonstrate the implementation; they are not recommended field values.
1000000
800
400
1.2
1.1
0.005
200000
Input definitions
N
STBInitial Oil-in-Place
Rsi
SCF/STBInitial Gas Solubility
Rs
SCF/STBGas Solubility at Current Conditions
Boi
bbl/STBOil FVF at Initial Reservoir Pressure
Bo
bbl/STBOil FVF at Current Reservoir Pressure
Bg
bbl/SCFGas Formation Volume Factor at Current Reservoir Pressure
Np
STBCumulative Oil Production
Output definitions
Gp
Cumulative Gas Production
N
Initial Oil-in-Place (rearranged)
Rsi
Initial Gas Solubility (rearranged)
Rs
Gas Solubility at Current Conditions (rearranged)
Boi
Oil FVF at Initial Pressure (rearranged)
Bo
Oil FVF at Current Pressure (rearranged)
Bg
Gas Formation Volume Factor (rearranged)
Np
Cumulative Oil Production (rearranged)
Engineering use, assumptions, and limits
Use this formula when the listed inputs (N, Rsi, Rs, Boi, Bo, Bg, Np) 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.
Frequently asked questions
What inputs does the Cumulative Gas Production – Tarner’s Method calculator need?
The calculation uses Initial Oil-in-Place (N), Initial Gas Solubility (Rsi), Gas Solubility at Current Conditions (Rs), Oil FVF at Initial Reservoir Pressure (Boi), Oil FVF at Current Reservoir Pressure (Bo), Gas Formation Volume Factor at Current Reservoir Pressure (Bg), Cumulative Oil Production (Np). Enter values on the units shown beside each field.
What result does this calculator return?
The primary result is cumulative gas production in SCF. The formula section shows the declared relationship, variables, and a reproducible default calculation.
What should I check before using the result?
Confirm the unit basis, source applicability, and input quality. The calculation does not replace a full engineering model or operating procedure. Mixing unit systems without converting the inputs.
Source and record status
Source metadata identifies the relationship implemented by the calculator. Check the cited edition, unit basis, and scope against the engineering case before operational use.
Ahmed, T., McKinney, P.D. (2005). Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter: 5, Page: 340.
Open source reference