PetrophysicsRock Properties
Sonic Porosity Raymer-Hunt-Gardner Method Formula
Sonic Porosity Raymer-Hunt-Gardner Method calculates sonic porosity for rock properties workflows in petrophysics.
How engineers use this formula
Use this formula when the listed inputs (Delta_t, Delta_t_ma, C_RHG) 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_sonic equals 0.209375 fraction.
Delta_tus/ft
80
Delta_t_maus/ft
55
C_RHGdimensionless
0.67
Inputs
Delta_t
us/ftSonic Log Transit Time Reading
Delta_t_ma
us/ftMatrix Transit Time
C_RHG
dimensionlessRaymer-Hunt-Gardner Empirical Constant
Outputs
Phi_sonic
fraction
Sonic Porosity
Delta_t
us/ft
Sonic Log Transit Time Reading
Delta_t_ma
us/ft
Matrix Transit Time
C_RHG
dimensionless
Raymer-Hunt-Gardner Empirical Constant
Source and review
reviewedFormation Evaluation and Petrophysics, Core Laboratories (2005)
Core Laboratories. 2005. Formation Evaluation and Petrophysics, Page 87.
Source