PetrophysicsRock Properties
Density Log Porosity from Bulk Density Formula
Density Log Porosity from Bulk Density calculates density-derived porosity for rock properties workflows in petrophysics.
How engineers use this formula
Use this formula when the listed inputs (rho_b, rho_ma, rho_f) 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 equals 0.181818 fraction.
rho_bg/cm^3
2.35
rho_mag/cm^3
2.65
rho_fg/cm^3
1
Inputs
rho_b
g/cm^3Formation Bulk Density
rho_ma
g/cm^3Matrix Density
rho_f
g/cm^3Average Pore-Fluid Density
Outputs
Phi
fraction
Density-Derived Porosity
rho_b
g/cm^3
Formation Bulk Density
rho_ma
g/cm^3
Matrix Density
rho_f
g/cm^3
Average Pore-Fluid Density
Source and review
reviewedBassiouni, Z. 1994. Theory, Measurement, and Interpretation of Well Logs, SPE Textbook Series Vol. 4, Chapter 8, Page 165.
Source