Productivity index index per unit of working reservoir thickness:

(1)	$\begin{array}{l}\displaystyle j = \frac{J}{h} =\frac{q/h}{\|p_e - p_{wf}\|}\end{array}$

where

$\begin{array}{l}J\end{array}$	Productivity Index
$\begin{array}{l}q\end{array}$	Flowrate (the specification of which may differ, see below)
$\begin{array}{l}h\end{array}$	Effective reservoir thickness
$\begin{array}{l}p_e\end{array}$	Formation pressure
$\begin{array}{l}p_{wf}\end{array}$	Bottom hole pressure at sandface

The definition of flowrate $\begin{array}{l}q\end{array}$ and formation pressure $\begin{array}{l}p_e\end{array}$ may vary depending on application of productivity index.

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See also