Three porosity computations are available

  • Total Porosity from Neutron-Density logs
  • Density Porosity from the Bulk Density log
  • Sonic Porosity from the Compressional sonic log.


The page will be updated with more information soon.


9.5.1  Density Porosity

The DPHI curve is computed from the Bulk Density curve using selected values of matrix density and formation fluid density.

9.5.2  Sonic Porosity

The SPHI curve is computed from the DT compressional sonic curve, using either the Wyllie or Raymer-Hunt-Gardner method.

9.5.3  Total Porosity

The current implementation computes and apparent total porosity and grain density to give the curves PHIA and RHGA.

A "Shale Point" is required for this computation, and a link to the NPHI-RHOB crossplot is provided to assist in interactively selecting this point.

To pick the Shale point:

  • first click on the crossplot with the left mouse button, and a cross will appear on the crossplot.
  • second, right click on the crossplot to shown the drop-down menu.  Select "Pick Shale/Clay points", then next select  "Select Shale Point".

Once this is done, the updated values will appear in the processing window.