Analysis of a well from a PI test
Input(s)
P: Average Reservoir Pressure (psi)
q: Flow Rate (STB/day)
\(P_{w f}\): Well Flowing Pressure (psi)
\(\mathrm{k}\): Permeability \((\mathrm{mD})\)
B: Volume Factor (RB/STB)
\(\mathrm{h}\): Thickness of Reservoir ( \(\mathrm{ft}\) )
\(\mu\): Oil Viscosity \((\mathrm{cP})\)
\(r_{e}\): Drainage Radius (ft)
\(r_{w}\): Wellbore Radius (ft)
Output(s)
J: Productivity index (STB/day/psi)
\(k_{j}\): Average Permeability \((\mathrm{mD})\)
s: Skin Factor (dimensionless)
Formula(s)
\[
\begin{gathered}
J=\frac{q}{P-P_{w f}} \\
k_{j}=141.2 * J * B * \mu * \frac{\ln \left(\frac{r_{e}}{r_{w}}\right)-0.75}{h} \\
s=\left(\frac{k}{k_{j}}-1\right) *\left(\ln \left(\frac{r_{e}}{r_{w}}\right)-0.75\right)
\end{gathered}
\]
Reference(s)
Lee, J., Rollins, J. B., & Spivey, J. P. (2003). Pressure Transient Testing (Vol. 9). Richardson, Texas: Society of Petroleum Engineers, Page: 16.