PetroCalcHubFree
Reservoir EngineeringFluid Flow in Porous Media

Drainage Radius from Area Formula

re=43560Aπr_e=\sqrt{\frac{43560A}{\pi}}

Drainage Radius from Area calculates drainage radius for fluid flow in porous media workflows in reservoir engineering.

Calculate

How engineers use this formula

Use this formula when the listed inputs (A) are known and the assumptions behind the cited fluid flow in porous media 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, r_e equals 744.73025 ft.

Aacre

40

Inputs

A

acre

Drainage Area

Outputs

r_e

ft

Drainage Radius

A

acre

Drainage Area

Source and review

reviewed

AAPG Wiki. Fluid flow fundamentals, radius of drainage expression.

Source

Related formulas and calculators

Average Permeability for Linear Flow in Layered Beds
Permeability
Average Permeability for Linear Flow - Series Beds
Permeability
Average Permeability for Parallel-Layered Systems
Permeability
Average Permeability in Radial Systems
Permeability
Klinkenberg Apparent Gas Permeability
Permeability
Jones-Owens Klinkenberg Slip Factor
Permeability