Geology Reference
In-Depth Information
a)
b)
Single Interface Model
Wedge Model
+
Shale
0
Ampl.
Offset
Sand
-
c)
d)
Layered Model
2D Model
Figure 2.20
Types of seismic models; (a) single interface model, (b) three-layer wedge model, (c) 1D layered model, (d) 2D model calculated
at a given reflectivity angle.
Synthetic seismogram with
different pulse shapes
Figure 2.21
Synthetic seismograms
with varying symmetrical wavelet shapes
from broad to sharp (re-drawn and
Lithology
Im
pedan
ce
Rc
- +
1
3
4
5
6
often instructive. This can be a useful way to appreci-
ate which geological units can be resolved with the
current data and how much improvement in band-
width (by new acquisition or reprocessing) would be
needed to resolve more detail (
Fig. 2.21
).
Sometimes, multi-layered models can be too com-
plex, combining so many ingredients that it becomes
hard to understand how changes in individual layer
properties will affect the seismic response without
constructing a very large and unwieldy suite of models.
The 1D synthetics can be made more sophisti-
cated by including propagation modes other than
primaries-only, for example multiples and mode
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