Pore pressure of shale (Flemings)
Input(s)
\(S_{v}\): Sonic Velocity \((\mathrm{ft} / \mathrm{s})\)
\(\beta_{c}\): Compressibility \((1 / \mathrm{psi})\)
\(\phi_{o}\): Initial Porosity (fraction)
\(\mathrm{t}\): Sonic Travel Time (s)
\(\emptyset\): Porosity from Sonic Log (fraction)
Output(s)
\(P_{p}\): Pore Pressure \((\mathrm{psi})\)
Formula(s)
\[
\boldsymbol{P}_{p}=S_{v}-\left(\left(\frac{1}{\boldsymbol{\beta}_{c}}\right) * \ln \left(\frac{\phi_{o}}{\emptyset}\right)\right)
\]
Reference(s)
Mark D. Zoback, Reservoir Geomechanics, Cambridge University Press, UK, Page: 48.