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 a reservoir |
dV = dx \, dy \, dz | Volume element of a reservoir |
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}), \, s_g({\bf r}) | Oil saturation and Gas saturation at location {\bf r} |
B_o(p_i, T_i), \, B_g(p_i, T_i) | Oil FVF and Gas FVF at Initial formation pressure and temperature |
R_s(p_i, T_i), \, R_v(p_i, T_i) | Solution GOR and Vaporized Oil Ratio at Initial formation pressure and temperature |