Harmonic Analysis: Six-Segment Downhole Acoustic Waveguide - Measurement While Drilling Signal Analysis, Optimization and Design - page 79

P in Drillpipe
Hz Source Position Xs(ft)
1 5 10 15 22
1 0.9422 0.9411 0.9397 0.9383 0.9363
12 0.7485 0.6084 0.4309 0.2536 0.0744
20 0.2628 0.0810 0.1687 0.3998 0.7142
30 0.0308 0.1750 0.4183 0.6466 0.9248
40 0.0894 0.3047 0.5551 0.7694 0.9828
50 0.1961 0.4372 0.6970 0.8861 0.9974

P/ '

P/ P in Upper Annulus

Hz Source Position Xs(ft)
1 5 10 15 22
1 0.05932 0.05928 0.05924 0.05921 0.05920
12 0.08162 0.07647 0.07108 0.06725 0.06516
20 0.06470 0.05813 0.05056 0.04458 0.04104
30 0.04583 0.04053 0.03357 0.02727 0.02305
40 0.03245 0.02904 0.02374 0.01822 0.01398
50 0.03154 0.02956 0.02447 0.01819 0.01266

'

Figure 2.8a. Transmission efficiency p/'p in drillpipe and annulus.

Figure 2.8b. P drillpipe /'p in drillpipe versus source position and frequency.

Figure 2.8c. P annulus /'p in annulus versus source position and frequency.