Figure F6. Example waveforms from the IDEAL sonic-while-drilling tool, showing the main arrivals at the four receivers (receiver distances above the source are 3.04 m for R1, 3.25 m for R2, 3.45 m for R3, and 3.66 m for R4) at depths (A) 262.15 mbsf (5064.05 mbrf) and (B) 397.58 mbsf (5199.48 mbrf; depths are measured to midway between R2 and R3) in Hole 1173B. Arrows indicate the first arrival of a leaky P-wave (LP) mode. C, D. Contour plots of coherence against slowness and arrival time for the wavetrains in (A) and (B). The diagonal lines show the limits within which real arrivals are expected; peaks outside these limits are likely to be noise or aliased signal. Peaks due to the leaky P-wave mode are indicated by LP. Diagram courtesy of V. Pistre, Schlumberger.

Figure F6. Example waveforms from the IDEAL sonic-while-drilling tool, showing the main arrivals at the four receivers (receiver distances above the source are 3.04 m for R1, 3.25 m for R2, 3.45 m for R3, and 3.66 m for R4) at depths (A) 262.15 mbsf (5064.05 mbrf) and (B) 397.58 mbsf (5199.48 mbrf; depths are measured to midway between R2 and R3) in Hole 1173B. Arrows indicate the first arrival of a leaky P-wave (LP) mode. C, D. Contour plots of coherence against slowness and arrival time for the wavetrains in (A) and (B). The diagonal lines show the limits within which real arrivals are expected; peaks outside these limits are likely to be noise or aliased signal. Peaks due to the leaky P-wave mode are indicated by LP. Diagram courtesy of V. Pistre, Schlumberger.