Neutron Log Porosity

Calculating neutron log porosity

This program calculates porosities from either sidewall neutron or compensated neutron logs, correcting for shale. Since the neutron log is calibrated to read porosity directly, the correction used in this program shows what the shale-corrected neutron porosity would be for different matrix values. Shale porosity is read directly from the log in an adjacent shale bed.

Note that the GRclean reading should represent the lowest GR recorded on the well log, while the GRshale reading should be read in an adjacent shale bed to the zone of interest.

The program first corrects the neutron porosity for shale, then for lithology (to convert to a limestone matrix).


Do you want to save your calculations? The input box at the very bottom of the screen records all the inputs and outputs for each calculation run. To save this information, select all the text in the box and copy it, then open a spreadsheet and paste it in as comma-separated values. Each data type will land in its own column, and each calculation run, or depth, will occupy a row. Format the spreadsheet to separate rows into different geologic formations, and you're done. Isn't that easier than writing everything down?

Don't have a spreadsheet handy? If you are working on a phone or a tablet, you can still copy the text and paste it into a note or an email.

The Recording box will reset if you press the "Help" or "Reset" buttons, or if you navigate to a different page.