PetrophysicsElectrical Properties
Effect of Clay on Conductivity Formula
Effect of Clay on Conductivity calculates formation conductivity with clay contribution for electrical properties workflows in petrophysics.
How engineers use this formula
Use this formula when the listed inputs (C_w, F, C_s) are known and the assumptions behind the cited electrical properties 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, C_o equals 0.09 1/(ohm m).
C_w1/(ohm m)
1.2
Fdimensionless
20
C_s1/(ohm m)
0.03
Inputs
C_w
1/(ohm m)Conductivity of Water
F
dimensionlessFormation Factor
C_s
1/(ohm m)Conductivity Contribution Due to Salinity or Clay
Outputs
C_o
1/(ohm m)
Formation Conductivity with Clay Contribution
C_w
1/(ohm m)
Conductivity of Water
F
dimensionless
Formation Factor
C_s
1/(ohm m)
Conductivity Contribution Due to Salinity or Clay
Source and review
reviewedEllis, D.V. and Singer, J.M. 2008. Well Logging for Earth Scientists, Second Edition. Springer, Chapter 4, Page 74.
Source