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.