Full-waveform static corrections using blind channel identification

Full-waveform static corrections using blind channel identification

van Vossen, R.
Trampert, J.
TNO Defensie en Veiligheid

2007

Near-surface wavefield perturbations can be very complex and completely mask the target reflections. Despite this complexity, conventional methods rely on parameterizations characterized by simple time and amplitude anomalies to compensate for these perturbations. Determining and compensating for time shifts is generally referred to as (residual) static corrections, whereas surface-consistent deconvolution techniques deal with amplitude anomalies. We present an approach that uses the full waveform to parameterize near-surface perturbations. Therefore, we refer to this method as waveform statics. Important differences from conventional static corrections are that this approach allows time shifts to vary with frequency and takes amplitude variations directly into account. Furthermore, the procedure is fully automated and does not rely on near-surface velocity information. The waveform static corrections are obtained usingblind channel identification and applied to the recordings using multichannel deconvolution. As a result, the method implicitly incorporates array forming. The developed method is validated on synthetic data and applied to part of a field data set acquired in an area with significant near-surface heterogeneity. The source and receiver responses obtained are strongly correlated to the near-surface conditions and show changes, both in phase and frequency content, along the spread. The application of the waveform statics demonstrates that they not only correct for near-surface wavefield perturbations, but also strongly reduce coherent noise. This results in substantial improvements, both in trace-to-trace coherency and in depth resolution. In addition, the procedure delineates reflection events that are difficult to detect prior to our proposed correction. Based on these results, we conclude that complex near-surface perturbations can be successfully dealt with using the multichannel, full-waveform, static-correction procedure. © 2007 Society of Exploration Geophysicists. All rights reserved.

Physics
Geophysical signal processing
Seismic waves
Seismology
Blind channel identification
Near-surface velocity information
Communication channels (information theory)
Identification (control systems)
Parameterization
Perturbation techniques
Signal processing
Sound recording
Amplitude
Deconvolution
Waveform analysis

http://resolver.tudelft.nl/uuid:6426382d-0833-49a6-80a4-2186033f1599

https://doi.org/10.1190/1.2742651

240072

Geophysics, 72 (4), U55-U66

article