# Dimensionless pressure (radial-flow/constant rate production)

## Input(s)

\(p_{i}\): Initial Reservoir Pressure (psi)

\(\mathrm{p}\): Reservoir Thickness (psi)

\(\mathrm{k}\): Permeability \((\mathrm{mD})\)

h: Reservoir Thickness (ft)

q: Formation Volume Factor (STB/day)

B: Volume Factor (RB/STB)

\(\mu\): Oil Viscosity \((\mathrm{cP})\)

## Output(s)

\(P_{d}\): Dimensionless Pressure (dimensionless)

## Formula(s)

\[
P_{d}=\frac{k * h}{141.2 * q * B * \mu} *\left(p_{i}-p\right)
\]

## Reference(s)

Lee, J., Rollins, J. B., & Spivey, J. P. (2003). Pressure Transient Testing (Vol. 9). Richardson, Texas: Society of Petroleum Engineers, Page: 8.