Geology Petrophysical Cementation Exponent M Calculator
FIT fully brine-saturated core ArchieF=aφ^(−m) data, not supplied exponent forward resistance or partial-saturation estimate. Caller independently establishes matching units, evidence, method edition and applicability; output is not compliance, diagnosis, work-safety approval, geological identity or validated hazard prediction.
Description
A cementation exponent describes the fitted relationship between porosity and electrical formation factor in an adopted power-law model.
A cementation exponent describes the fitted relationship between porosity and electrical formation factor in an adopted power-law model.1
Fitting the exponent and prefactor requires matched measurements and does not establish a universal rock constant. Use this tool to calculate petrophysical cementation exponent m from the supplied measurements and assumptions.
When to use Geology Petrophysical Cementation Exponent M Calculator
Use this tool to calculate petrophysical cementation exponent m from the supplied measurements and assumptions. Establish the measurement units, sampled interval, calibration or model edition and geological assumptions before entering data.
How to use Geology Petrophysical Cementation Exponent M Calculator and understand its results
- Establish the measurement units, sampled interval, calibration or model edition and geological assumptions before entering data.
- Enter corePorosities, fullySaturatedFormationFactors, using the field meanings and rules below, then run the tool.
- Read fittedCementationExponent, fittedTortuosityCoefficient, fitRSquared. Interpret the fields using their units, signs and evidence conventions below.
- If input validation fails, correct the reported field and run again. Before applying the result, check reference scope, model assumptions and any missing evidence or placeholder values.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| corePorosities | Core porosities | list of number | Required |
| fullySaturatedFormationFactors | Fully saturated formation factors | list of number | Required |
Enter at least two aligned porosities in (0,1] and positive fully saturated formation factors. Fit ln(formationFactor) against ln(porosity), requiring nonzero log-porosity variance. Return minus the slope as exponent, exp(intercept) as prefactor and log-space R². The fitted exponent is not constrained positive.
F=a×porosity^(−m); m=−logFitSlope; a=exp(logFitIntercept) Use the exact units, boundary rules, ordering and missing-evidence conventions above.
| Output field | Meaning | Value type |
|---|---|---|
| fittedCementationExponent | Fitted Cementation Exponent; follow the units, sign, ordering and evidence convention stated above | number |
| fittedTortuosityCoefficient | Fitted Tortuosity Coefficient; follow the units, sign, ordering and evidence convention stated above | number |
| fitRSquared | Fit R Squared; follow the units, sign, ordering and evidence convention stated above | number |
{
"input": {
"corePorosities": [
0.25,
0.5
],
"fullySaturatedFormationFactors": [
16,
4
]
},
"output": {
"fittedCementationExponent": 2,
"fittedTortuosityCoefficient": 1,
"fitRSquared": 1
}
}Limitations and assumptions
Fitting the exponent and prefactor requires matched measurements and does not establish a universal rock constant. Interpretation depends on the units, sampling scope and exact model described above.
All listed fields require explicit values. Unexpected fields, incorrect types, nonfinite numbers and sparse evidence arrays fail validation; the specific bounds and alignment requirements are stated above. Extremely large inputs or outputs can also be rejected. An input error is distinct from a successful result reporting false, no matches or missing evidence.
Alternative or Complementary methods
Use Geology Petrophysical Dielectric Permittivity Calculator for this related task: Effective dielectric permittivity depends on how constituent phases and pore fluids are mixed.
Use Geology Effective Porosity Calculator when its separate inputs and assumptions fit the question: Effective porosity excludes independently estimated dead-end volume from a supplied connected pore volume.
References
Similar or alternative tools
- Geology Petrophysical Dielectric Permittivity Calculator
Effective dielectric permittivity depends on how constituent phases and pore fluids are mixed.
- Geology Effective Porosity Calculator
Effective porosity excludes independently estimated dead-end volume from a supplied connected pore volume.