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Darcy-Weisbach Tubing Friction Pressure Drop Formula

ΔPf=fDρLv22gcD144\Delta P_f=\frac{f_D\rho Lv^2}{2g_cD\cdot144}

Darcy-Weisbach Tubing Friction Pressure Drop calculates friction pressure drop for well performance workflows in production engineering.

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How engineers use this formula

Use this formula when the listed inputs (f_D, rho, L, v, D_i) are known and the assumptions behind the cited well 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, DeltaP_f equals 66.317162 psi.

f_Ddimensionless

0.02

rholbm/ft3

50

Lft

5000

vft/s

5

D_iin

2.441

Inputs

f_D

dimensionless

Darcy Friction Factor

rho

lbm/ft3

Fluid Density

L

ft

Tubing Section Length

v

ft/s

Average Flow Velocity

D_i

in

Tubing Inside Diameter

Outputs

DeltaP_f

psi

Friction Pressure Drop

D_ft

ft

Tubing Inside Diameter

v

ft/s

Average Flow Velocity

Source and review

reviewed

Penn State PNG 301. Darcy-Weisbach equation for single-segment oil production wells.

Source

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