Hingle Crossplot True Resistivity Formula
Hingle Crossplot True Resistivity calculates true rock resistivity for resistivity logs workflows in petrophysics.
How engineers use this formula
Use this formula when the listed inputs (S_w, R_w, phi, a, n, m) 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, R_t equals 5.73921 ohm m.
0.6
0.1
0.22
1
2
2
Inputs
S_w
fractionWater Saturation
R_w
ohm mFormation Water Resistivity
phi
fractionPorosity
a
dimensionlessPore Geometry Coefficient
n
dimensionlessSaturation Exponent
m
dimensionlessCementation Exponent
Outputs
R_t
True Rock Resistivity
S_w
Water Saturation
R_w
Formation Water Resistivity
phi
Porosity
a
Pore Geometry Coefficient
n
Saturation Exponent
m
Cementation Exponent
Source and review
reviewedTheory, Measurement, and Interpretation of Well Logs, Bassiouni, Z. (1994)
Bassiouni, Z. 1994. Theory, Measurement, and Interpretation of Well Logs. SPE Textbook Series Vol. 4, Chapter 13, Page 268.
Source