Dimensionless buildup pressure for steam or gas flow
Input(s)
\(k\): Effective Permeability of Flowing Phase (D)
\(h\): Net Formation Thickness (m)
\(P_{i}\): Initial Reservoir Pressure (psi)
\(P_{w s}\): Shut in Pressure (psi)
\(M\): Molecular Weight \((\mathrm{g} / \mathrm{g} \mathrm{mol})\)
\(q\): Production Rate (tons/h \((1000 \mathrm{~kg} / \mathrm{h}))\)
Z: Real Gas Law Deviation Factor (Ratio)
\(\mu\): Viscosity of Flowing Fluid (cP)
\(T\): Absolute Formation Temperature \(\left({ }^{\circ} \mathrm{K}\right)\)
Output(s)
\(P_{D s}\): Dimensionless Pressure (dimensionless)
Formula(s)
\[
P_{D s}=\frac{\operatorname{Mkh}\left(P_{i}^{2}-P_{w s}{ }^{2}\right)}{0.01291 q \mu Z T}
\]
Reference(s)
Ramey Jr, H. J. (1981). Reservoir Engineering Assessment of Geothermal Systems. Department of Petroleum Engineering, Stanford University, Page: (5.7).