Reservoir EngineeringRock Properties
Total Porosity from Bulk and Grain Volume Formula
Total Porosity from Bulk and Grain Volume calculates total porosity for rock properties workflows in reservoir engineering.
How engineers use this formula
Use this formula when the listed inputs (V_b, V_g) 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 0.2 fraction.
V_bcm^3
100
V_gcm^3
80
Inputs
V_b
cm^3Bulk Rock Volume
V_g
cm^3Grain Volume
Outputs
phi_t
fraction
Total Porosity
V_b
cm^3
Bulk Rock Volume
V_g
cm^3
Grain Volume
Source and review
reviewedAAPG Wiki. Porosity, laboratory determination equations 1-3.
Source