A pore volume fraction of bulk rock volume containing the hydrodynamically connected fluids (also called free fluids) within each pore element:
\phi_e = \frac{V_\phi}{V_r} |
The reason to introduce this concept is that a part of the actual inter-grain void is filled with shale thus reducing the actual volume available for fluids.
It splits into two components:
subject to condition:
\phi_e = \phi_{\rm opn} + \phi_{\rm cls} |
Effective porosity is a function of reservoir pressure at a given location
\phi_e(\mathbf{r}, \ p) = \phi_{e0}(\mathbf{r}) \exp \left[ - \int_{p_i}^p c_r(p) \, dp \right] |
where
pore compressibility (see also Pore compressibility @model ) | |
initial formation pressure |
Petroleum Industry / Upstream / Subsurface E&P Disciplines / Petrophysics (PP) / Volumetric Rock Model
[ Basic reservoir properties ] [ Pore volume ] [ Connected pore volume ] [ Closed pore volume ] [ Porosity ] [ Open porosity ] [ Closed porosity ]
[ Pore compressibility @model ]