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.