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.