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During a seismic survey, it can't be guaranteed that all the receivers have the same response. Neither can we promise that the energy for all shots have same energy. So, the recorded amplitude difference between traces will include not only rock information but also artifacts caused by different sources and receivers. We should remove such artifacts before performing AVA analysis.
For each trace, its amplitude square A_{t} can be expressed as
<B><I>AI>_{<I>tI>}=<I>RI>_{<I>tI>}<I>SI>_{<I>tI>}<I>GI>_{<I>tI>}<I>UI>_{<I>tI>}
B> 


(5) 
Here, R_{t} is the component from the unique receiver the trace is corresponding to; S_{t} is from the unique source the trace is corresponding to; G_{t} corresponding to geometrical spreading for this trace; and U_{t} is the remaining amplitude component which contains the information related to rock properties.
The way we balanced the amplitude is the following:
 1.
 Extract the same depth window for all traces and calculate the sum of the amplitude square for all traces in this window.
 2.
 Using the conjugate gradient method to solve for R_{t}, S_{t}, G_{t} and U_{t} using (5).
 3.
 The problem will be underdetermined. We regularize the problem by applying Laplacian to G_{t} and U_{t} because they should be spatially continuous.
 4.
 After solving R_{t}, S_{t}, G_{t} and U_{t} for each trace, we will divide all traces by their corresponding R_{t}, S_{t} and G_{t} to remove the artifacts.
Next: Extract AVA attributes and
Up: Methodology to evaluate the
Previous: Using multiple realization method
Stanford Exploration Project
11/11/2002