Pressure required to overcome mud's gel strength in annulus

Input(s)

y: Gel Strength of Drilling Fluid $\left(\mathrm{lb} / 100 \mathrm{ft}^{2}\right)$

$\mathrm{D}_{\mathrm{h}}$: Hole Diameter (in.)

$\mathrm{D}_{\mathrm{p}}$: Pipe Diameter (in.)

L: Length of Drillstring (ft)

Output(s)

$\mathrm{P}_{\mathrm{m}}$: Pressure Required (psi)

Formula(s)

$$ \mathrm{P}_{\mathrm{m}}=\frac{\mathrm{y} * \mathrm{~L}}{300 *\left(\mathrm{D}_{\mathrm{h}}-\mathrm{D}_{\mathrm{p}}\right)} $$

Reference(s)

Lapeyrouse, N. J., 2002, Formulas and Calculations for Drilling, Production and Workover, Second Edition, Gulf Professional Publishing, Page: 79.