Electrochemical Potential - SP Log Formula
Electrochemical Potential - SP Log calculates electrochemical potential for electrical properties workflows in petrophysics.
How engineers use this formula
Use this formula when the listed inputs (t_Cl, R_gas, T_a, F_faraday, a_1, a_2) 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, E_c equals 0.083332 V.
0.6
8.314
350
96485.336
1
0.1
Inputs
t_Cl
dimensionlessChloride Ion Transference Number
R_gas
J/(mol K)Gas Constant
T_a
KAbsolute Temperature
F_faraday
C/molFaraday Constant
a_1
dimensionlessActivity of First Electrolyte
a_2
dimensionlessActivity of Second Electrolyte
Outputs
E_c
Electrochemical Potential
t_Cl
Chloride Ion Transference Number
a_1
Activity of First Electrolyte
a_2
Activity of Second Electrolyte
Source and review
reviewedBassiouni, Z. 1994. Theory, Measurement, and Interpretation of Well Logs. SPE Textbook Series Vol. 4, Chapter 6, Page 131.
Source