A method to average the multi-phase fluid density depending on the relative phase mobilities:
| \rho(p, T) = \frac{ M_{rw} \rho_w + M_{ro} (1 + R_{sn}) \rho_o + M_{rg} (1+R_{vn}) \rho_g }{ M_{rw} + M_{ro} (1 + R_{sn}) + M_{rg} (1+R_{vn}) } |
as function of reservoir pressure p and temperature T
where
This concept gives more wight