Stripping/snubbing calculations - Height gain and casing pressure from stripping into influx

Input(s)

$C_{d p}$: Capacity of Drill Pipe or tubing $(\mathrm{bbl} / \mathrm{ft})$

$D_{d p}$: Displacement of Drill Pipe,Drill Collar or tubing $(\mathrm{bbl} / \mathrm{ft})$

$C_{a}$: Annular Capacity $(\mathrm{bbl} / \mathrm{ft})$

L: Length of Drill Pipe Stripped (ft)

$\mathrm{G}$: Gradient of Mud (psi/ft)

$G_{i}$: Gradient of Influx (psi/ft)

Output(s)

$\mathrm{H}$: Height gain from stripping into influx $(\mathrm{ft})$

P: Casing Pressure increase from stripping into influx (psi)

Formula(s)

$$ \begin{aligned} & H=L * \frac{C_{d p}+D_{d p}}{C_{a}} \\ & P=H *\left(G-G_{i}\right) \end{aligned} $$

Reference(s)

Formulas and Calculations for Drilling, Production and Workover, Second Edition, Lapeyrouse, Page: 140.