5 0 2 0 0
-1 0 deg 9 0 Sonde Deviation
O ffline E nergy
0
M aximum 0 E nergy
0 0 1 0 0
M inimum E nergy
5 1 0 0 0
H ole Azimuth deg 3 6 0
0
Total Azimuth deg 3 6 0
0
H ole Diameter in.
2 0
G amma R ay gAP I 1 5 0
F ast Shear Azimuth Azimuth U ncertainty
-9 0 deg 9 0
Compressional ∆T Stoneley ∆T
µ s/ ft µ s/ ft %
3 6 0 1 ,2 0 0
Time-B ased Anisotropy 1 0 0
0
∆T-B ased Anisotropy 1 0 0
%
Anisotropy F lag, % 1 6
0 2 4 6 0 2 0 0 2 0 0
∆T-B ased Slow Shear µ s/ ft
1 ,2 0 0 0
∆T-B ased F ast Shear µ s/ ft
1 ,2 0 0 0 Slow W aveform µ s 3 0 ,0 0 0 F ast W aveform µ s 3 0 ,0 0 0 W indow Stop µ s 3 0 ,0 0 0 W indow Start µ s 3 0 ,0 0 0 2 0 0
F ast Shear Coherence
µ s/ ft 1 ,2 0 0 2 0 0 F requency Analysis E nergy
F ast Shear µ s/ ft
Slow Shear Coherence
1 ,2 0 0 2 0 0 µ s/ ft 1 ,2 0 0 2 0 0 Slowness- F requency Analysis E nergy
Slow Shear µ s/ ft
Slowness-
1 ,2 0 0
1 ,2 5 0
1 ,3 0 0
1 ,3 5 0
1 ,4 0 0
1 ,4 5 0
1 ,5 0 0
1 ,5 5 0
1 ,6 0 0
> Shear-w ave slow nesses com puted from ex ural-w ave logging in the ex trem ely slow Antelope form ation, Cy m ric eld, California. In the diatom ite zone, dow n to 1, 5 00 ft, shear slow nesses in Track 3 average 7 00 µ s/ ft and approach 9 00 µ s/ ft in som e intervals. Below that, shear slow nesses decrease to ab out
4 00 µ s/ ft. The large separation b etw een m inim um and m ax im um of ine energy in the depth track indicates anisotropy . Track 1 show s gam m a ray ( green) , hole diam eter ( y ellow ) , hole azim uth ( light b lue) and azim uth of the continually rotating tool ( dark b lue) . Azim uth of the fast shear w ave, show n in Track 2
( red) , is relatively constant in the anisotropic zone ab ove 1, 5 00 ft, in spite of continual tool rotation. In addition to fast ( red) and slow ( b lue) shear slow nesses estim ated from dispersion analy sis, Track 3 show s Stoneley -w ave slow ness ( b lack ) , P-w ave slow ness ( green curve) , and slow ness-b ased ( left edge of track ) and tim e-b ased ( right edge of track ) anisotropies. Track 4 show s the w aveform s and tim e w indow s used for ex ural-w ave analy sis. Slow ness-tim e- coherence proj ections for fast and slow shear are show n in Track 5 and Track 7 , respectively . Slow ness-freq uency -analy sis ( SFA) proj ections for fast and slow shear are show n in Track 6 and Track 8, respectively . ( Modi ed from Walsh et al, reference 8. )
20
Oilfield Review
Depth, ft
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