Shallow Water Demultiple

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swd_shot_with

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Left, Without SWD: Right, With SWD

Shallow Water Demultiple (SWD) provides improved results for multiple attenuation where water depths are too shallow to apply SRME directly. In shallow water, the waterbottom reflection needed by SRME to predict multiples may not be recorded with sufficient fidelity.

SWD is data-driven and uses the information from multiples in the data for predicting and removing water layer multiples.

Features and Benefits

In shallow water, creates a model of the waterbottom from the multiples in the data
Uses waterbottom model to predict all waterbottom multiples in the data
Multiple model can be adaptively subtracted
Provides superior demultiple over SRME where recorded waterbottom is indistinct, e.g. shallow water
Attenuates higher order low frequency multiples where the wavelets overlap, making Tau-p deconvolution difficult
Can be used in combination with other demultiple techniques

These example displays are from offshore China. The first waterbottom multiple is about 40ms below the primary. Higher order multiples are lower in frequency so wavelets overlap, making difficult attenuation by deconvolution. SWD successfully attenuates both the first order and higher order multiples.


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