Rawlins-Schellhardt Gas Deliverability Rate Calculator
Enter the required inputs, confirm the units, and run the calculator to solve q_g. Review the formula source and assumptions before using the result in engineering work.
Calculation context and source notes
Rawlins-Schellhardt Gas Deliverability Rate calculates gas flow rate for inflow performance workflows in production engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
Use this formula when the listed inputs (C_rs, P_r, P_wf, n_rs) are known and the assumptions behind the cited inflow performance relationship match the engineering case being checked.
Solves for
q_g (MSCF/day)
Best next page
Formula, variables, and sourceFormula, variables, and default calculation
Reproducible default result
With the default values shown below, the calculation returns q_g = 87.209596 MSCF/day. Defaults demonstrate the implementation; they are not recommended field values.
0.0003
3000
1500
0.8
Input definitions
C_rs
MSCF/day/psi^(2n)Rawlins-Schellhardt Deliverability Coefficient
P_r
psiaAverage Reservoir Pressure
P_wf
psiaFlowing Bottom-Hole Pressure
n_rs
dimensionlessRawlins-Schellhardt Deliverability Exponent
Output definitions
q_g
Gas Flow Rate
C_rs
Rawlins-Schellhardt Deliverability Coefficient
delta_p2
Pressure-Squared Drawdown
P_r
Average Reservoir Pressure
P_wf
Flowing Bottom-Hole Pressure
n_rs
Rawlins-Schellhardt Deliverability Exponent
Engineering use, assumptions, and limits
Use this formula when the listed inputs (C_rs, P_r, P_wf, n_rs) are known and the assumptions behind the cited inflow performance 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 Rawlins-Schellhardt Gas Deliverability Rate calculator need?
The calculation uses Rawlins-Schellhardt Deliverability Coefficient (C_rs), Average Reservoir Pressure (P_r), Flowing Bottom-Hole Pressure (P_wf), Rawlins-Schellhardt Deliverability Exponent (n_rs). Enter values on the units shown beside each field.
What result does this calculator return?
The primary result is gas flow rate in MSCF/day. 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.
Johnston and Lee, SPE 23440. Estimating Stabilized Gas-Well Deliverability with the Rawlins-Schellhardt Method.
Open source reference