The key measurement is the p-wave velocity and s-wave velocity .
The equivalent measurement is travel time: and .
Table 1. Typical values of wave velocities.
Media | P-wave velocity | S-wave velocity |
---|---|---|
, m/s | , m/s | |
Rocks | 4,500 | 2,300 |
Casing | 5,850 | 7,800 |
Weight cement | 4,000 | 2,400 |
Conventional cement | 2,800 | 1,900 |
Low-density cement | 1,950 | 1,200 |
Ultra-low-density cement | 1,600 | 1,100 |
Water | 1,500 | 1,000 |
Dvorkin, TIME-AVERAGE EQUATION REVISITED, 2001.pdf Dr. Paul Glover, Petrophysics MSc Course Notes, Sonic Log, Chapter 16.PDF |