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Drilling EngineeringDrilling Hydraulics

Bit Nozzle Pressure Loss Formula

Pb=156.5Q2MW(N12+N22+N32)2P_b = \frac{156.5Q^2MW}{(N_1^2+N_2^2+N_3^2)^2}

Bit Nozzle Pressure Loss calculates bit nozzle pressure loss for drilling hydraulics workflows in drilling engineering.

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How engineers use this formula

Use this formula when the listed inputs (Q, MW, N_1, N_2, N_3) are known and the assumptions behind the cited drilling hydraulics 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, P_b equals 3,018.904321 psi.

Qgpm

600

MWppg

10

N_11/32 in

12

N_21/32 in

12

N_31/32 in

12

Inputs

Q

gpm

Circulation Rate

MW

ppg

Mud Weight

N_1

1/32 in

Nozzle 1 Size

N_2

1/32 in

Nozzle 2 Size

N_3

1/32 in

Nozzle 3 Size

Outputs

P_b

psi

Bit Nozzle Pressure Loss

Q

gpm

Circulation Rate

MW

ppg

Mud Weight

N_1

1/32 in

Nozzle 1 Size

N_2

1/32 in

Nozzle 2 Size

N_3

1/32 in

Nozzle 3 Size

Source and review

reviewed

Lapeyrouse, N.J. Formulas and Calculations for Drilling, Production and Workover, 2nd Edition, Page 170.

Source

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