Despite of terminological similarity there is a big difference in the way WFP 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 pressure | Flow rate | Prroducivity Index |
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DM |
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WFP | | field-average pressure within the drainage area | | surface liquid rate (each fluid component separately) | | LaTeX Math Inline |
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body | J_W = \frac{q_W}{p_R - p_{wf}} |
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| , LaTeX Math Inline |
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body | J_O = \frac{q_O}{p_R - p_{wf}} |
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| , LaTeX Math Inline |
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body | J_G = \frac{q_G}{p_R - p_{wf}} |
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WT | | average pressure value at the boudary of drainage area | | total flowrate at sandface: LaTeX Math Inline |
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body | q_t = B_w \, q_W + B_o \, q_O + B_g \, ( q_G - R_s q_O) |
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| – for Black Oil LaTeX Math Inline |
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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 |
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| – for Volatile Oil LaTeX Math Inline |
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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 |
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| – for pseudo-components of Compositional Model | | total multiphase productivity index LaTeX Math Inline |
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body | J_t = \frac{q_t}{p_e - p_{wf}} |
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| WFP | Well Testing |
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Formation pressure | | field-average pressure within the drainage area
| | average pressure value at the boudary of the drainage area
|
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Flow rate | | surface liquid rate (each fluid component separately) | | total flowrate at sandface: LaTeX Math Inline |
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body | q_t = B_w \, q_W + B_o \, q_O + B_g \, ( q_G - R_s q_O) |
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| – for Black Oil
LaTeX Math Inline |
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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 |
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| – for Volatile Oil LaTeX Math Inline |
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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 |
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| – for pseudo-components of Compositional Model |
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Prroducivity Index | | LaTeX Math Inline |
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body | J_W = \frac{q_W}{p_R - p_{wf}} |
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, LaTeX Math Inline |
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body | J_O = \frac{q_O}{p_R - p_{wf}} |
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, LaTeX Math Inline |
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body | J_G = \frac{q_G}{p_R - p_{wf}} |
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| | total multiphase proudcivity productivity index LaTeX Math Inline |
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body | J_t = \frac{q_t}{p_e - p_{wf}} |
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