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

q_W = a \, \cdot q_O + b

where

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 pay reservoir


oil productivity index of oil pay reservoir

formation pressure water reservoir

water productivity index of oil pay reservoir


In practical applications, the equation  is often considered through the averaged value:

<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:

t-weighted

q-weighted

< 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


Petroleum Industry / Upstream /  Production / Subsurface Production / Field Study & Modelling /  Production Analysis / Watercut Diagnostics