Page 305 - Principles of Applied Reservoir Simulation 2E

290 Principles of Applied Reservoir Simulation

available from well logs such as shear wave logging tools or laboratory measure-
ments of parameters such as acoustic velocities or the dry frame Poisson's ratio.

Bulk and Shear Moduli for Quartz Sand
Correlation Valid for Porosity < 35%

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35
Porosity
Bulk (psia) -»- Shear (psia)~* Bulk (GPa) -"- Shear (GPa)

Figure 27-3. Correlation for bulk and shear moduli.

Acoustic Impedance and Reflection Coefficients
Acoustic impedance Z is defined as

Z = 9 BV P (27.14)

The reflection coefficient RC at the interface between two layers with acoustic
impedances Z, and Z 2 is given by
- Z,
Z 2
RC = —— (27.15)
+ Z,j
Z, 2
The transmission coefficient TC is
2Z.
TC = (27J6)
z + z

or TC = 1 - RC.