J = \frac{q}{|p_e - p_{wf}|}

where

flowrate (the specification of which may differ, see below)

formation pressure

bottom hole pressure at sandface


The definition of flowrate  and formation pressure  may vary depending on application.


Overall concept is applicable to both producers and injectors but can be split into specific definitions:

Productivity Index of producerInjectivity Index of injector


J^{\uparrow} = \frac{q^{\uparrow}}{p_e - p_{wf}}



J^{\downarrow} = \frac{q^{\downarrow}}{p_{wf} - p_e}


production rate

injection rate


The PI concept also applies to aquifer expansion:

J^{\downarrow} = \frac{q^{\downarrow}}{p(t) - p_{AQ}(t)}

where

volumetric water inflow rate from aquifer into hydrocarbon reservoir

formation pressure in hydrocarbon reservoir

formation pressure in aquifer



See Also


Petroleum Industry / Upstream / Production / Subsurface Production / Well & Reservoir Management

Subsurface E&P Disciplines / Production Technology 

Injectivity Index ]

Definition specifics on formation pressure and productivity index  ] [ Sandface Productivity Index ] [ Surface Productivity Index ]