Microseismic Monitoring and Geomechanical Modelling of CO2 - bris

CHAPTER 6.
GENERATING ANISOTROPIC SEISMIC MODELS BASED ON GEOMECHANICAL SIMULATION
Initial average aspect ratio (× 10 −3 )
7
6
5
4
3
2
1
Sandstone
Carbonate
Anhydrite
Conglomerate
Tight gas sandstone
Shale
Tight gas shale
Clay
Clair samples
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Initial normalised crack density
Figure 6.11: Best fit values for ξ 0 and a 0 for dry samples published in the literature for a variety
of lithologies.
Initial average aspect ratio (x 10 -3 )
7
6
5
4
3
2
1784
1788
Shale
Tight gas shale
Clay
Clair samples
1950
1
2194
1909
Global trend
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Initial normalised crack density
Figure 6.12: Best fit values for ξ 0 and a 0 for the clay rich samples.
When attempting to use data from literature, a problem often encountered is that the core observations
provided are often limited. For example, detailed core description such as classification of
sample integrity, coring damage, mineral constituents, hand samples, and back-scatter electron micrographs
can all provide valuable information to complement ultrasonic measurements but may not
be provided in the published work. Hence, we are limited to very broad conclusions based on global
trends.
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