Formula 3.21
Dimensionless pressure (radial-flow/constant pressure production)
Input(s)
$P_{i}$: Initial Reservoir Pressure (psi)
$P$: Final Reservoir Pressure (psi)
$P_{w f}$: Well Flowing Pressure (psi)
Output(s)
$P_{d}$: Dimensionless Pressure (dimensionless)
Formula(s)
$$ P_{d}=\frac{P_{i}-P}{P_{i}-P_{w f}} $$
Reference(s)
Lee, J., Rollins, J. B., \& Spivey, J. P. (2003). Pressure Transient Testing (Vol. 9). Richardson, Texas: Society of Petroleum Engineers, Page: 9.