PetrophysicsResistivity Logs
Shell Formation Factor - Low-Porosity Carbonates Formula
Shell Formation Factor - Low-Porosity Carbonates calculates formation resistivity factor for low-porosity non-fractured carbonates for resistivity logs workflows in petrophysics.
How engineers use this formula
Use this formula when the listed inputs (phi) are known and the assumptions behind the cited resistivity logs 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, F_l equals 23.630671 dimensionless.
phifraction
0.2
Inputs
phi
fractionPorosity
Outputs
F_l
dimensionless
Formation Resistivity Factor for Low-Porosity Non-Fractured Carbonates
Source and review
reviewedBassiouni, Z. 1994. Theory, Measurement, and Interpretation of Well Logs, SPE Textbook Series Vol. 4, Chapter 1, Page 10.
Source