Total volume of subsurface oil reserves in NTP conditions
(1) | V_{\rm STOIIP} = \int_{\Omega} B^{-1}_o(p_i({\bf r}), T_i({\bf r})) s_o({\bf r}) \phi_e({\bf r}) dV |
where
\Omega | Petroleum reservoir |
{\bf r} = (x,y,z) | Position vector to some location in reservoir |
dV = dx \, dy \, dz | Volume element |
p_i({\bf r}), T_i({\bf r}) | Initial formation pressure and temperature at location {\bf r} |
\phi_e({\bf r}) | Effective porosity at location {\bf r} |
s_o({\bf r}) | Oil saturation at location {\bf r} |
B_o(p_i, T_i) | Oil formation volume factor |