According to Wikipedia,

**Sonic logging** is a well logging tool that provides a formation’s interval transit time, designated as , which is a measure of a formation’s capacity to transmit seismic waves. Geologically, this capacity varies with lithology and rock textures, most notably decreasing with an increasing effective porosity

Nickzom Calculator+ (Professional Version) – **The Calculator Encyclopedia** solves calculations on porosity for sonic log and shows the steps carefully.

The parameters to input to get the answer for your porosity problem are:

- Internal Transit Time of Formation
- Internal Transit Time of Matrix
- Internal Transit Time of the Fluid in the Well Bore
- Compaction Factor

Select **Geology **from the drop down.

Click on **Open Section**

Click on **Porosity | Sonic Log**

Now enter the values of the parameters

Finally, click on **Calculate**

According to Wikipedia – In Calculating Porosity

Many relationships between travel time and porosity have been proposed, the most commonly accepted is the Wyllie time-average equation. The equation basically holds that the total travel time recorded on the log is the sum of the time the sonic wave spends travelling the solid part of the rock, called the rock matrix and the time spent travelling through the fluids in the pores.

One can access Nickzom Calculator+ (Professional Version) – **The Calculator Encyclopedia** via any of these channels:

Web – https://www.nickzom.org/calculator-plus

Android (Paid) – https://play.google.com/store/apps/details?id=org.nickzom.nickzomcalculator

Apple (Paid) – https://itunes.apple.com/us/app/nickzom-calculator/id1331162702?mt=8