350
10
20
30
80
80
40
0
32
40
0
32
70
0
31
50
50
31
0
70
60
30
0
40
40
r
Bo
290
50
280
20
10
270
260
30
250
50
0
24
0
24
40
12
0
12
0
50
110
110
40
60
0
23
0%
70
22
0
Polar Contour Key
0
14
70
13
0
13
0
0
23
60
0
14
22
0
80
200
190
0
15
21
0
160
200
170
180
190
SHADOW ZONE ATTENUATION PLOT
POLAR POLE PLOT COLORED BY DIP TYPE
STEREOGRAPHIC PROJECTION, UPPER HEMISPHERE
1128.7 TO 2002.6 MEASURED DEPTH (m)
160
Frequency Within
18 Degrees
21
0
80
5%
180
260
20
30
100
100
20
90
10
10
n
io
ct
re
Di
90
270
10
250
80
20
30
e
ol
eh
80
280
30
70
50
70
290
60
60
30
0
60
Created in RDA dip interpretation program
10
0
33
30
0
33
0
340
20
170
0
0
15
350
340
Shadow Zone Key
0%
Attenuation
90%
SHADOW ZONE ATTENUATION PLOT
POLAR POLE PLOT COLORED BY DIP TYPE
STEREOGRAPHIC PROJECTION, UPPER HEMISPHERE
1128.7 TO 2002.6 MEASURED DEPTH (m)
Created in RDA dip interpretation program
Polar plots illustrating a shadow zone in a horizontal well. The left plot is a shaded contour plot of fracture-pole frequency within 18º
of each grid point. On the right is a plot of the individual fracture poles on top of a shadow zone attenuation based on the
borehole orientation within the interval. It is a common misconception in polar plots that this pattern would represent two
broad fracture sets. Instead, it appears that the absence of poles in the NE/SW direction is caused by the shadow zone rather
than a separation between fracture sets. (The polar plots are in stereographic projection and upper hemisphere.)