PO.IPR.HW.SS.PI.ByEconomides.Centered


Description

Calculates steady state productivity index for horizontal well using Economides model for centered well (Zw = h/2), [STB/(d.psi)]. Economides et al. (1994) correlation.

Syntax

=PO.IPR.HW.SS.PI.ByEconomides.Centered(L, Rw, Xe, Ye, h, Kx, Ky, Kz, Bl, Ul)

Parameters

Parameter Description
L Length of horizontal section, [ft].
Rw Wellbore radius, [ft].
Xe Drainage extent in x-direction (along well), [ft].
Ye Drainage extent in y-direction (perpendicular), [ft].
h Reservoir thickness, [ft].
Kx Permeability in x-direction, [mD].
Ky Permeability in y-direction, [mD].
Kz Permeability in z-direction (vertical), [mD].
Bl Liquid formation volume factor, [bbl/STB].
Ul Liquid viscosity, [cP].

SI Unit Version

Lambda Name PO.IPR.HW.SS.PI.ByEconomides.Centered.SI
Formula
=LAMBDA(L, Rw, Xe, Ye, h, Kx, Ky, Kz, Bl, Ul, LET( L_ft, PO.UnitConverter(L, "m", "ft"), Rw_ft, PO.UnitConverter(Rw, "m", "ft"), Xe_ft, PO.UnitConverter(Xe, "m", "ft"), Ye_ft, PO.UnitConverter(Ye, "m", "ft"), h_ft, PO.UnitConverter(h, "m", "ft"), result_STBdpsi, PO.IPR.HW.SS.PI.ByEconomides.Centered(L_ft, Rw_ft, Xe_ft, Ye_ft, h_ft, Kx, Ky, Kz, Bl, Ul), result_STBdpsi * PO.UnitConverter(1, "bbl/d", "m3/d") / PO.UnitConverter(1, "psi", "kPa")))
SI Parameters
Parameter Unit Description
L m Length of horizontal section, [m]
Rw m Wellbore radius, [m]
Xe m Drainage extent in x-direction (along well), [m]
Ye m Drainage extent in y-direction (perpendicular), [m]
h m Reservoir thickness, [m]
Kx - Permeability in x-direction, [mD]
Ky - Permeability in y-direction, [mD]
Kz - Permeability in z-direction (vertical), [mD]
Bl - Liquid formation volume factor, [m3/sm3]
Ul - Liquid viscosity, [cP]
How to save as a reusable Excel function

LAMBDA is a built-in Excel feature (Microsoft 365) that lets you create custom functions without VBA. The formula above works as-is when pasted into a cell.

To save a LAMBDA as a reusable named function:

  1. Go to Formulas → Name Manager → New
  2. Enter a name, e.g. PO.IPR.HW.SS.PI.ByEconomides.Centered.SI
  3. In Refers to, paste the LAMBDA formula without the trailing invocation (...)
  4. Click OK

Now use =PO.IPR.HW.SS.PI.ByEconomides.Centered.SI(...) anywhere in your workbook.

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