Critical annular velocity and critical flow rate
Input(s)
0600: 600 Viscometer Dial Reading (dimensionless)
0300: 300 Viscometer Dial Reading (dimensionless)
Dh: Diameter of Hole (in.)
Dp: Diameter of Drill Pipe (in.)
MW: Mud Weight in Use (ppg)
Output(s)
n: Power Constant (dimensionless)
\(\mathrm{K}\): Constant (dimensionless)
\(\mathrm{x}\): Constant (dimensionless)
AVc: Critical Annular Velocity (ppg)
GPMc: Critical Flow Rate (ppg)
Formula(s)
\[
\begin{gathered}
\mathrm{n}=3.32 * \log \left(\frac{\theta 600}{\theta 300}\right) \\
\mathrm{K}=\frac{\theta 600}{1022^{\mathrm{n}}} \\
\mathrm{x}=81600 * \mathrm{~K} * \frac{(\mathrm{n})^{0.387}}{\left((\mathrm{Dh}-\mathrm{Dp})^{\mathrm{n}}\right) * \mathrm{MW}} \\
\mathrm{AVc}=\mathrm{x}^{\frac{1}{2-(\mathrm{n})}} \\
\mathrm{GPMc}=\mathrm{AVc} * \frac{\mathrm{Dh}^{2}-\mathrm{Dp}^{2}}{24.5}
\end{gathered}
\]
Reference(s)
Lyons, W. C., Carter, T., and Lapeyrouse, N. J., 2012, Formulas and Calculations for Drilling, Production and Workover, Third Edition, Gulf Professional Publishing, Page: 212.