Page 198 - Reservoir Geomechanics

180 Reservoir geomechanics

a.
S Hmax
A

A-CENTRAL FAULT

HIGH REFLECTIVITY
DUE TO GAS IN THE B N
BRENT RESERVOIR
C

o
62 N
D
NORWAY
REDUCED REFLECTIVITY
DUE TO GAS LEAKAGE
E
o
61 N
S Hmax
Bergen
0 1 2 3 4 5
o
o
o
o
o
2 E 3 E 4 E 5 E 6 E
Km
b.
A B Well
n = 254 n = 78 A B C D E

S Hmax = 101° ± 10° S Hmax = 102° ± 10°
C D
n = 221 n = 618

S Hmax = 107° ± 11° S Hmax = 97° ± 9°
E
n = 90 n = 1261
Data from
all wells
S Hmax = 97° ± 11° S Hmax = 100° ± 10°
Figure 6.7. Drilling-induced tensile fractures in five wells in the Visund field in the northern North
Sea indicate a remarkably uniform stress field both spatially and with depth (after Wiprut, Zoback
et al. 2000). The rose diagrams illustrate how uniform the tensile fracture orientations are with
depth in each well and the field as a whole. The length of each well logged with an electrical
imaging device is shown in white in the diagram in the lower right. The drilling-induced tensile
fractures are shown by the vertical black lines.