Crossflow Index Formula
Crossflow Index calculates crossflow index for permeability and flow workflows in reservoir engineering.
How engineers use this formula
Use this formula when the listed inputs (N_pcf, N_pncf, N_pu) are known and the assumptions behind the cited permeability and flow 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, CI equals 0.5 dimensionless.
8000
6000
10000
Inputs
N_pcf
STBOil Recovery from Layered System with Crossflow
N_pncf
STBOil Recovery from Stratified System with No Crossflow
N_pu
STBOil Recovery from Uniform System with Average Permeability
Outputs
CI
Crossflow Index
N_pcf
Oil Recovery from Layered System with Crossflow (rearranged)
N_pncf
Oil Recovery from Stratified System with No Crossflow (rearranged)
N_pu
Oil Recovery from Uniform System with Average Permeability (rearranged)
Source and review
reviewedWillhite, G.P. (1986). Waterflooding, Vol. 3. Richardson, Texas: Textbook Series, SPE, Chapter: 2, Page: 166.
Source