# Stripping/snubbing calculations - Breakover point between stripping and snubbing

## Input(s)

$$D p$$: Pipe or collar OD (in.)

P: Wellbore Pressure (psi)

$$W_{d c}$$: Weight of Drill Collar (lb/ft)

L: Drill Collar Length (ft)

BF: Buoyancy Factor (dimensionless)

$$W_{d p}$$: Drill Pipe Weight $$(\mathrm{lb} / \mathrm{ft})$$

## Output(s)

F: Force created by wellbore pressure on Drill collar or pipe (lb)

W: Weight of Drill Collar (lb)

$$W_{a d p}$$: Additional weight required from Drill Pipe (lb)

$$L_{b p}$$: Length of Drill Pipe required to reach over breakover point (ft)

$$L_{d s}$$: Length of Drill string req to reach breakover point (ft)

## Formula(s)

$\begin{gathered} F=D p^{2} * 0.7854 * P \\ W=W_{d c} * L * B F \\ W_{a d p}=F-W \\ L_{b p}=\frac{W_{a d p}}{B F * W_{d p}} \\ L_{d s}=L+L_{b p} \end{gathered}$

## Reference(s)

Formulas and Calculations for Drilling, Production and Workover, Second Edition, Lapeyrouse, Page: 139.

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