Amount of fluid mass passing through a certain area per unit time:

\dot m_A = \frac{d m}{ d  t} \Big|_A = j_m \cdot A

where

SI unit	Metric unit	Oilfield units
kg /s	kg /s	lb/s

\dot m_A = \rho_A \cdot q_A

In case of Volatile Oil Reservoir the connection with surface flowrates will be:

q_O = \frac{m_O}{\rho_O}

q_G = \frac{m_G}{\rho_G}

q_W = \frac{m_W}{\rho_W}

See also