Geoscience Reference
In-Depth Information
A benefit of inverting angle stacks to elastic impedance is that a wavelet will be
estimated from well ties for each angle range independently. This takes care of the
shift to lower frequencies normally seen on the far traces, but more importantly allows
the amplitude of the near and far traces to be correctly matched. This removes one
of the chief uncertainties in quantitative interpretation of AVO effects. As compared
with AVO interpretation on reflectivity data, additional benefits are the reduction of the
effect of tuning and the ability to distinguish lateral change in a reservoir from changes
in the overburden, just as in acoustic impedance inversion.
Various approaches have been taken to combining the elastic impedance information
from different angle ranges to yield rock parameters. Possibilities include the estimation
of Poisson's ratio or of compressional and shear elastic moduli, which can be diagnostic
of different lithologies or fluid fill. However, the results are sensitive to noise in the data,
and careful comparison of the predicted rock parameters with well data is an essential
QC step.
References
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