Production EngineeringInjection Wells
Radial Water Injectivity Index Formula
Radial Water Injectivity Index calculates radial water injectivity index for injection wells workflows in production engineering.
How engineers use this formula
Use this formula when the listed inputs (k_rw, k, h, mu_w, B_w, r_e, r_w, s) are known and the assumptions behind the cited injection wells 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, I_w equals 3.297081 STB/day/psi.
k_rwfraction
0.6
kmD
100
hft
50
mu_wcP
0.7
B_wrb/STB
1.02
r_eft
1000
r_wft
0.328
sdimensionless
1
Inputs
k_rw
fractionRelative Permeability to Water
k
mDAbsolute Permeability
h
ftNet Pay Thickness
mu_w
cPWater Viscosity
B_w
rb/STBWater Formation Volume Factor
r_e
ftDrainage Radius
r_w
ftWellbore Radius
s
dimensionlessSkin Factor
Outputs
I_w
STB/day/psi
Radial Water Injectivity Index
Source and review
reviewedBaker, R.O., Yarranton, H.W. and Jensen, J.L. 2015. Practical Reservoir Engineering and Characterization, radial Darcy field-unit water equation.
Source