Cement Bond Logging - Cased-Hole Log Analysis and Reservoir Performance Monitoring - page 208

Free Pipe in Deviated Hole

Where the pipe rests on the low side of a deviated hole, acoustic coupling can take
place between the pipe and the formation. In that case, the VDL may show forma-
tion arrivals. Do not be fooled. Diagnostics are:

1. Transit time slightly reduced (tool eccentered)
2. Amplitude high
3. VDL shows weak casing arrivals and strong-to-moderate formation arrivals

Figure 12.23 illustrates this case

Fig. 12.23 CBL/VDL in deviated hole. Courtesy Schlumberger