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Annular Velocity

Speed of mud returning up the annulus, key to carrying cuttings out.

Formula

V_a = \frac{24.5 \, Q}{D_h^2 - D_p^2}

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Variables

V_aAnnular velocity (ft/min)

QFlow rate (gpm)

D_hHole diameter (in)

D_pPipe diameter (in)

Example

Q=400, D_h=8.5, D_p=5: V_a ≈ 220 ft/min

Did You Know?

Too slow and cuttings pile up; too fast and the borehole wall erodes — velocity must be tuned.

petroleum annular velocity

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