Despite of terminological similarity there is a big difference in the way WFP and Well Testing deal with formation pressure and flowrates which results in a big difference in productivity index definition and corresponding analysis. This difference is summarized in the table below:
| WFP | Well Testing |
---|
Formation pressure | – field-average pressure within the drainage area
| – average pressure value at boudary of the drainage area
| Flow rate | surface liquid rate LaTeX Math Inline |
---|
body | q_{\rm liq}=W, q_O+, q_W |
---|
| – surface liquid rate | total flowrate at sandface LaTeX Math Inline |
---|
body | q_t = B_w \, q_W + \frac{B_o - R_s B_g}{1 - R_v R_s} \, q_O + \frac{B_g - R_v B_o}{1 - R_v R_s} \, q_G |
---|
| – total flowrate at sandface | Prroducivity Index | LaTeX Math Inline |
---|
body | J_{sw} = \frac{q_W}{p_R - p_{wf}} |
---|
| , LaTeX Math Inline |
---|
body | J_{\rm liq}}so} = \frac{q_O}{p_R - p_{wf}} |
---|
| , g g | LaTeX Math Inline |
---|
body | J_t = \frac{q_t}{p_e - p_{wf}} |
---|
|
|
|