The qOW plotis based on the following correlation between oil production rate and water production rate:

q_W = a \, \cdot q_O + b

a = J^{-1}_O \cdot ( J_{1W} + J_{2W})

b = J_{2W} \cdot (p^*_2 - p^*_1)

where

	water production rate	oil production rate
formation pressure in oil pay reservoir	water productivity index of oil & water reservoir	oil productivity index of oil pay reservoir
formation pressure water reservoir	water productivity index of water reservoir

For the case of water reservoir pressure is higher than that of oil: .

In practical applications, the equation is often considered through the weighted average values:

<q_W> = a \, \cdot <q_O> + \, b

where

are weighted average of and

There are different ways to calculate weighted average of the dynamic variable, for example:

< A >_t \ = \frac{1}{t} \int_o^t A(t) \, dt

<A>_q \ = \frac{1}{Q(t)} \int_o^t A(t) \, q(t) \, dt

See Also