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Amplitude Balance

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 At 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, Rt is the component from the unique receiver the trace is corresponding to; St is from the unique source the trace is corresponding to; Gt corresponding to geometrical spreading for this trace; and Ut 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 Rt, St, Gt and Ut using (5).
3.
The problem will be underdetermined. We regularize the problem by applying Laplacian to Gt and Ut because they should be spatially continuous.
4.
After solving Rt, St, Gt and Ut for each trace, we will divide all traces by their corresponding Rt, St and Gt to remove the artifacts.

next up previous print clean
Next: Extract AVA attributes and Up: Methodology to evaluate the Previous: Using multiple realization method
Stanford Exploration Project
11/11/2002