Dimensionless pressure drop across a skin at the well face
Input(s)
\(k\): Effective Permeability of Flowing Phase (D)
\(h\): Net Formation Thickness (m)
\(P_{i}\): Initial Reservoir Pressure (psi)
\(P_{1 h r}\): Pressure at 1 hour on semi-log straight line or its extension (psi)
\(P_{w s}\): Shut in Pressure (psi)
\(P_{w f}\): Bottomhole Pressure at a flowing well (psi)
\(v_{s c}\): Specific Volume at Standard Conditions \((\mathrm{cc} / \mathrm{g})\)
\(q\): Production Rate \(\left(\mathrm{m}^{3} / \mathrm{h}\right)\)
B: Formation Volume Factor (Reservoir Volume/Standard Volume)
\(\mu\): Viscosity of Flowing Fluid (cP)
\(c_{t}\): Total System Effective Isothermal Compressibility \(\left(\mathrm{kg} / \mathrm{cm}^{2}\right)^{-1}\)
\(r_{w}\): Well Radius \((\mathrm{m})\)
\(m\): Slope of Semi-Log Graph \(\left(\mathrm{kg} / \mathrm{cm}^{2}\right) / \log\) cycle for Liquid
\(\varnothing\): Porosity (Per cent)
Output(s)
\(P_{D w}\): Dimensionless Pressure at the well face (dimensionless)
\(s\): Skin Effect (dimensionless)
Formula(s)
Reference(s)
Ramey Jr, H. J. (1981). Reservoir Engineering Assessment of Geothermal Systems. Department of Petroleum Engineering, Stanford University, Page: (5.13).