# Dimensionless buildup pressure for field calculations

## Input(s)

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

\(P_{w s}\): Shut in Pressure (psi)

\(m\): Slope of Semi-Log Graph \(\left(\mathrm{kg} / \mathrm{cm}^{2}\right) / \log\) cycle for Liquid

## Output(s)

\(P_{D s}\): Dimensionless Pressure (dimensionless)

## Formula(s)

\[
P_{D s}=\frac{\left(P_{i}-P_{w s}\right)}{0.87 m}
\]

## Reference(s)

Ramey Jr, H. J. (1981). Reservoir Engineering Assessment of Geothermal Systems. Department of Petroleum Engineering, Stanford University, Page: (5.8).