Rawlins-Schellhardt Deliverability Exponent from Two Test Points Formula
Rawlins-Schellhardt Deliverability Exponent from Two Test Points calculates rawlins-schellhardt deliverability exponent for inflow performance workflows in production engineering.
How engineers use this formula
Use this formula when the listed inputs (q_g1, q_g2, delta_p2_1, delta_p2_2) 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.
Default example
Using the default inputs, n_rs equals 0.8 dimensionless.
57.38114998740225
89.78415232709284
4000000
7000000
Inputs
q_g1
MSCF/dayGas Flow Rate at Test Point 1
q_g2
MSCF/dayGas Flow Rate at Test Point 2
delta_p2_1
psi^2Pressure-Squared Drawdown at Test Point 1
delta_p2_2
psi^2Pressure-Squared Drawdown at Test Point 2
Outputs
n_rs
Rawlins-Schellhardt Deliverability Exponent
q_g1
Gas Flow Rate at Test Point 1
q_g2
Gas Flow Rate at Test Point 2
delta_p2_1
Pressure-Squared Drawdown at Test Point 1
delta_p2_2
Pressure-Squared Drawdown at Test Point 2
C_rs
Rawlins-Schellhardt Deliverability Coefficient
Source and review
reviewedPenn State PNG 301. Deliverability Testing, backpressure plot slope and intercept.
Source