The key measurement is the p-wave velocity V_p and s-wave velocity V_s.
The equivalent measurement is travel time: \tau_p = 1/V_p and \tau_s = 1/V_s.
Table 1. Typical values of wave velocities.
Media | P-wave velocity | S-wave velocity |
|---|---|---|
V_p, m/s | V_s, m/s | |
| Rocks | 4500 | 2320 |
| Casing | 5860 | 7850 |
| Weight cement | 4000 | 2400 |
| Conventional cement | 2823 | 1920 |
| Low-density cement | 1960 | 1200 |
| Ultra-low-density cement | 1600 | 1100 |
| Water | 1500 | 1000 |