Despite of terminological similarity there is a big difference in the way Dynamic Modelling,  Well Flow Performance and Well Testing deal with formation pressure and flowrates which results in a difference in productivity index definition and corresponding analysis.

This difference is summarized in the table below:


Formation pressureFlow ratePrroducivity Index
DM

field-average pressure within the 9-cell area

phase flowrate at sandface:

(each fluid phase separately)

phase productivity index:


, ,

WFP

field-average pressure within the drainage area

surface liquid rate

(each fluid component separately)

fluid component productivity index:

, ,

WT

average pressure value at the boudary of drainage area

total flowrate at sandface:

– for Black Oil

– for Volatile Oil

or pseudo-components of Compositional Model

total multiphase productivity index: