Convert Velocity Voxel to Density

Use the Velocity to Density Conversion > Voxel option from the GM-SYS 3D Tools menu to convert a voxel containing seismic (P-wave) velocities into rock densities using one of several published methods.

Convert Velocity Voxel to Density dialog options

Input velocity voxel	Select an existing voxel containing velocity values to be converted. Script Parameter: VOXVEL2DEN.INPUT_VOXEL
Velocity units	Select the velocity units that the values in the input voxel represent. Script Parameter: VOXVEL2DEN.VELOCITY_UNITS
Output density voxel	Select the name of the new or existing voxel that will contain the calculated density values. Script Parameter: VOXVEL2DEN.OUTPUT_VOXEL
Density units	Select the density units that the values in the output voxel represent. Script Parameter: VOXVEL2DEN.DENSITY_UNITS
Method	Select the conversion method from the list. The valid range of velocities for each method is shown. Script Parameter: VOXVEL2DEN.METHOD
Dummy outside range	Each conversion method is defined within a range of velocities (and corresponding densities). Check this box if you wish to dummy calculated values that fall outside of the defined range. Script Parameter: VOXVEL2DEN.USE_DUMMIES

Application Notes

Published empirical relationships between seismic velocity and bulk density of various rock types are commonly used in processing seismic data (Gardner et al.,1974¹; Brocher, 2005²). The Velocity to Density and Density to Velocity conversions utilize 5th order polynomial expansions to approximate several of these relationships to less than 0.001 g/cm³ variance. Velocity to Density function and the inverse Density to Velocity function should match to within 4 significant figures.

Additional Custom Methods

Additional Velocity-to-Density conversion functions may be added by editing the %USERPROFILE%\Documents\Geosoft\Desktop Applications \csv\vel_density.csv file. The conversion must be represented by a 5th order or lower polynomial, as described in the file header. Coefficients are appropriate for Velocity units of m/s and Density units of g/cm³ and unit conversions are performed by the GXs.

References