Majalah Ilmiah UNIKOM
Vol.6, No. 2
186
H a l a m a n
The existence of fluid in fracture will raise
stiffness value of medium significantly, it is
caused by increasing compressibility K
f
.
NUMERICAL STUDY OF FLUID INCLUSION
EFFECT IN FRACTURE TO THE AVO
PARAMETER
Using MATLAB 6.5.1 we studied AVO
(amplitude various offset) parameter
change to the fluid change of fluid content
of fracture. This experiment is to design
the best AVO parameter that most
sensitive to detect fluid content in fracture.
We use following data to model the AVO :
Physical data of upper Medium
Density
:1000 kg/m
3
a
: 900 m/s
b
: 500 m/s
Physical data of Lower Medium
Density
: 1473.9 kg/m
3
a
: 1842.10 m/s
b
: 1195.47 m/s
Anisotropy Degree
VTI :
HTI :
d : 0.1, e : 0,06 dan g : 0.08
Bulk Modulus of Fluids : 2.2 GPa (water)
Bulk Modulus of Material : 40 GPa
Porosity : 0,27
Figure 1, show the result of the modeling.
CONCLUSIONS
It is shown in figure 1 that we can model
the AVO response using MATLAB 6.5.1 as
numerical computation. According to the
result, we see that AVO respon is increase
with incident angle due to fluid inclusion
GPa
.
5
)
10
.
1842
)(
9
.
1473
(
C
2
2
o
33
GPa
9
.
1
)
29
.
1163
)(
9
.
1473
(
C
2
2
o
55
GPa
6
.
5
)
748
.
1941
)(
9
.
1473
(
C
2
2
o
11
GPa
2
.
2
)
21
.
1226
)(
9
.
1473
(
C
2
2
o
66
about 30 %. The increase is caused by
bulk modulus of the pore fluid.
REFERENCES
Thomsen, L. (1992). Seismic And Acous-
ticVelocities in Reservoir Rocks Volume
Geophysics Reprint
Series
Geophysicist
Pore Fluid
Effects on Seismic Anisotropy
ford Rock Physics and Borehole Project
Understanding Seis-
mic Anisotropy in Exploration an Exploi-
tation
scientist & engineers.
Brown R.J.S. & Korringa, J. (1975) On De-
pendence Of Elastic Properties Of a
Porous Rock on the Compressibility of
Geophysics
616
Fluid Substitution
Theories and Multicompnent Seismic
Characterization of Fractured Reser-
voir
Phenomena Colorado School of Mines.
Numeri-
cal Methods Using MATLAB
wood.
Ishaq, U.M. & Nurhandoko, E.B.
(December 2005).
Study of seismic
wave in fractured reservoir rock using
Empty pores
Water
Figure1
AVO Modeling Using MATLAB 6.5.1
USEP MOHAMAD ISHAQ