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Gas Deliverability Pressure-Squared Drawdown Formula

Δp2=Pr2Pwf2\Delta p^2=P_r^2-P_{wf}^2

Gas Deliverability Pressure-Squared Drawdown calculates pressure-squared drawdown for inflow performance workflows in production engineering.

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How engineers use this formula

Use this formula when the listed inputs (P_r, P_wf) 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, delta_p2 equals 6,750,000 psi^2.

P_rpsia

3000

P_wfpsia

1500

Inputs

P_r

psia

Average Reservoir Pressure

P_wf

psia

Flowing Bottom-Hole Pressure

Outputs

delta_p2

psi^2

Pressure-Squared Drawdown

P_r

psia

Average Reservoir Pressure

P_wf

psia

Flowing Bottom-Hole Pressure

Source and review

reviewed

Penn State PNG 301. Deliverability Testing, gas-well pressure-squared drawdown.

Source

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