Friction factor in drill pipe
Input(s)
\(\mu_{\mathrm{s}}\): Static Viscosity \((\mathrm{cP})\)
\(\sigma\): Normal Stess at Contact (psi)
\(\mathrm{k}\): Exponential Constant (dimensionless)
\(\mathrm{t}\): Average Contact Time (s)
\(\mathrm{V}_{\mathrm{t}}\): Trip Speed \((\mathrm{ft} / \mathrm{s})\)
\(\omega\): Angular Speed \((\mathrm{ft} / \mathrm{s})\)
Output(s)
\(\mu\): Constant (dimensionless)
Formula(s)
\[
\mu=\frac{\mu_{\mathrm{s}}}{1+\left(\frac{\mu_{\mathrm{s}} * \sigma *\left(\left(\mathrm{~V}_{\mathrm{t}}^{2}+\omega^{2}\right)^{0.5}\right)}{\mathrm{k} * \mathrm{t}}\right)}
\]
Reference(s)
Samuel. E Robello. 501 Solved Problems and Calculations for Drilling Operations. Sigma Quadrant. 2015. Houston, Texas, Page: 375.