Reservoir EngineeringFluid Flow in Porous Media
Pseudosteady-State Radial Productivity Index Formula
Pseudosteady-State Radial Productivity Index calculates pseudosteady-state productivity index for fluid flow in porous media workflows in reservoir engineering.
How engineers use this formula
Use this formula when the listed inputs (k, h, mu_o, B_o, r_e, r_w, s) are known and the assumptions behind the cited fluid flow in porous media relationship match the engineering case being checked.
Assumptions
- Input values are representative for the well, reservoir, fluid, or equipment case being evaluated.
- The declared units match the field-unit constants used in the formula.
- The cited formula applies to the selected petroleum engineering workflow.
Limitations
- The calculation does not replace a full engineering model or operating procedure.
- Accuracy depends on the source correlation, assumptions, input quality, and unit consistency.
Common mistakes
- Mixing unit systems without converting the inputs.
- Using default example values as field recommendations.
- Applying the formula outside the source assumptions.
Default example
Using the default inputs, J equals 1.59121 STB/day/psi.
kmD
100
hft
50
mu_ocP
2
B_obbl/STB
1.2
r_eft
1000
r_wft
0.328
sdimensionless
2
Inputs
k
mDPermeability
h
ftNet Pay Thickness
mu_o
cPOil Viscosity
B_o
bbl/STBOil Formation Volume Factor
r_e
ftDrainage Radius
r_w
ftWellbore Radius
s
dimensionlessSkin Factor
Outputs
J
STB/day/psi
Pseudosteady-State Productivity Index
Source and review
reviewedAAPG Wiki. Fluid flow fundamentals, productivity-index expression.
Source