PetrophysicsRock Properties
True Sonic Porosity from Compaction Correction Formula
True Sonic Porosity from Compaction Correction calculates true porosity for rock properties workflows in petrophysics.
How engineers use this formula
Use this formula when the listed inputs (Phi_a, C_p) are known and the assumptions behind the cited rock 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, Phi_t equals 0.25 fraction.
Phi_afraction
0.3
C_pdimensionless
1.2
Inputs
Phi_a
fractionCalculated Sonic Porosity Without Compaction Correction
C_p
dimensionlessCompaction Factor
Outputs
Phi_t
fraction
True Porosity
Phi_a
fraction
Calculated Sonic Porosity Without Compaction Correction
C_p
dimensionless
Compaction Factor
Source and review
reviewedCore Laboratories. 2005. Formation Evaluation and Petrophysics, Page 90.
Source