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Adaptive De-ghosting by Kurtosis Maximisation
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 77th EAGE Conference and Exhibition 2015, Jun 2015, Volume 2015, p.1 - 5
Abstract
We discuss the reasons for adaptive de-ghosting and its advantages. The success of broadband processing relies on de-ghosting accuracy, and because the parameters of the physical process determining the ghost reflection are not precisely known, de-ghosting cannot be purely deterministic. The physical entities determining the receiver ghost are the sea surface, the receiver depth and the water velocity and for de-ghosting purposes they can be represented by an effective ghost delay-time and sea surface reflection coefficient.
The de-ghosting optimisation metric we employ is based on the kurtosis of the data-autocorrelation. The kurtosis is a statistical measure often used to associate a measure of “peakedness” to a random variable. A synthetic example characterizes the main features of the adaptive procedure proposed, which can be sequenced in two steps. The optimisation of the ghost delay-time is robust to errors in the reflection coefficient and to noise, Therefore, it should be performed first. The reflection coefficient estimate is more sensitive to noise and requires the delay-time to be optimized in advance, and can therefore be carried out as a second step. A real data example demonstrates the applicability of the proposed method.