Geoscience Reference
In-Depth Information
Poisson Ratio and Lithology
0.5
Water
0.45
0.4
North Sea
Shale
Clays
0.35
Calcite
North S
ea
Chalk
high
porosity
0.3
Brine sand
Halite
0.25
32% Porosity Sand
0.2
0.15
Gas sand
0.1
Quartz
0.05
0
0
5
10
15
20
AI (km/s
.
g/cm
3
)
Fig. 5.2
Poisson's ratio vs acoustic impedance.
Energy Partitioning at an Interface
Reflected
Compressional
Reflected
Shear
Transmitted
Compressional
Transmitted
Shear
Critical
angle
Angle of
incidence
Critical
angle
Described by the
Zoeppritz
Equations
V
p
12 800 ft/s
V
s
8000 ft/s
ρ
2.4 g/cm
3
θ
V
p
21 000 ft/s
V
s
12 000 ft/s
ρ
2.65 g/cm
3
Fig. 5.3
Energy partitioning at an interface, after Dobrin
(1976),
Introduction to Geophysical
Prospecting
, reproduced with permission of the McGraw-Hill Companies.
