Page 106 - The Geological Interpretation of Well Logs
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- THE GEOLOGICAL INTERPRETATION OF WELL LOGS -
. CALIPER . BHC ABERRATIONS (a, b)
6 11 16
i’ l l 1 1 l 1 1
INTERVAL TRANSIT TIME microsec/fi
(a) 90 40
0 potiy yy a {yyy yy fy yy
cycle skipping
7 sonic
25m + |
{b) 0
| noise spikes
= cal
A
bit size |
7 =
15m 4
LSS ABERRATIONS (c, d)
(c) INT, TRANSIT TIME {d) INT. TRANSIT TIME
240 sift 40 240 uS/ft 40
oO L L 1 4
DTS
pore. wx |
4 mal n
=a P
wf =
4 +] pair
iC 10 separation
25m 5
P=paired spurious peaks
Figure 8.6 Unwanted environmental effects on the sonic log. (a2) BHC tool, cycle skipping; (6) BHC tool, noise spikes; (c, 4)
long-spacing tool, paired aberrations, DTS = short-spaced sonic, DTL = long-spaced sonic. The pairs are separated for the most
part by 1Oft, the compensation shift distance.
96
