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Lamda-mu-rho technique as a viable tool for litho-fluid
discrimination - The Niger-Delta example
Ujuanbi
O1, Okolie J. C2 and Jegede S.I1
1Department
of Physics, Ambrose Alli University, Ekpoma, Edo State,
Nigeria,
2Department
of Physics, Delta State University, Abraka, Delta State,
Nigeria
*Corresponding author.
E-mail:omiujuanbi@yahoo.com
Accepted 25
July 2008 |
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The focus
of this paper is to discriminate fluid and lithology in the
tertiary Niger Delta using the Lamda-mu-rho technique. This
involves the use of basic rock Physics, Amplitude Variation
with Offset (AVO), and seismic amplitude inversion to show
the effectiveness of this technique in an oil sand
reservoir. The data used in this study include pre-stack
seismic data and well log data. The result shows the
effectiveness of this technique for litho-fluid
discrimination irrespective of the geological setting. For
over a decade, there has been a lot of interest in the
extraction of information from Amplitude Variations with
Offset (AVO) for the determination of fluid content of
reservoirs.The work of Goodway et al, 1997, Gray and
Anderson, 2000 have shown with great success the Lambda-murho
technique for litho- fluid discrimination. This has wide
application in exploratory work and development of
reservoirs in various geological settings. Despite the
robustness of their work, David Gray 2001 suggested the
extraction of the fundamental rock properties
l
and
m
with the exclusion of density term
r.The
work was found to be an improvement on Goodway’s method in
that it produced data that were less noisy and stable (Quakenbush
et al., 2006). Reservoir characterization requires the
detection, identification, and quantification of thickness,
porosity, permeability, and fluid content. Unfortunately,
many of these reservoir parameters are not derivable from
seismic data. The only elastic parameters derivable from
seismic data are the Lame’s Constant (l,m),
velocity, poisson’s ratio and impedances. This is due to the
fact that these mentioned parameters are directly
responsible for seismic amplitude variation. In this paper,
a simultaneous inversion of prestack seismic data was done
with a view to obtaining the acoustic and shear impedances.
The aim was to verify Goodway et al. (1997) technique as a
viable tool for discriminating oil sand from shales within a
reservoir in the Niger Delta region of Nigeria.
Key
words: Fluid, lithology, Niger Delta, AVO, Lamda-mu-rho,
discrimination. |
