--> Abstract: Adaptive Surface Waves Attenuation from Wide-Azimuth Land Data, by David Le Meur, Nigel Benjamin, Teo Wah hong, Tom Van Dijk, and Paul Matheny; #90105 (2010)
[First Hit]

Datapages, Inc.Print this page

AAPG GEO 2010 Middle East
Geoscience Conference & Exhibition
Innovative Geoscience Solutions – Meeting Hydrocarbon Demand in Changing Times
March 7-10, 2010 – Manama, Bahrain

Adaptive Surface Waves Attenuation from Wide-Azimuth Previous HitLandNext Hit Previous HitDataNext Hit

David Le Meur1; Nigel Benjamin2; Teo Wah hong3; Tom Van Dijk4; Paul Matheny5

(1) Research, CGGVeritas, Massy, France.

(2) Previous HitSeismicNext Hit Processing, CGGVeritas, Muscat, Oman.

(3) Previous HitSeismicNext Hit Processing, CGGVeritas, Muscat, Oman.

(4) Processing & Imaging, Petroleum Development of Oman, Muscat, Oman.

(5) Previous HitAcquisitionNext Hit, Petroleum Development of Oman, Muscat, Oman.

Attenuation of Surface Waves is the first show stopper that is faced in Previous HitlandNext Hit Previous HitdataNext Hit processing. However, the characteristics of Surface Waves, Groundroll and Guided Waves, can be extracted from the input Previous HitdataNext Hit themselves to feed a cascaded adaptive filtering in order to remove these troublesome noises. This approach is done in the FX domain to model the signal and noise. The part of the model corresponding to the noise is then subtracted from the Previous HitdataNext Hit using a least squares approach. The benefit of such an approach is to wipe-out the Surface waves recorded on raw surface Previous HitseismicNext Hit Previous HitdataNext Hit. This constitutes a technical breakthrough for many difficult areas especially for modern surveys with Wide-Azimuth Previous HitacquisitionNext Hit.

The first issues that should be addressed in Previous HitlandNext Hit processing are the attenuation of Groundroll (GR) and Guided Waves (GW). Both are Surface Waves recorded on a vertical geophone and are the result of interfering P and SV waves that travel along or near the ground surface. GR is characterized by low velocity, low frequency and high amplitude and can be strongly dispersive and aliased. GW are visible on records as repeated linear arrivals on the longer offsets due to multiple refractions and/or converted refractions. GW are generated by some specific sub-surface geological conditions such as fast-slow-fast velocity interfaces at depth and these pollute the long offsets of Previous HitdataNext Hit with high amplitudes, fast velocity and higher frequency linear noises than GR but with weaker dispersion. A cascaded application of an adaptive noise attenuation taking into account the GR and GW characteristics can fully benefit Wide-Azimuth Previous HitacquisitionNext Hit and will have a major impact on the S/N ratio and stack response. More of the acquired Previous HitdataNext Hit can be utilized to create the stack (e.g. incidence angle might be increased from 25/30° to 40/45°) and this has many positive benefits such as increased accuracy of velocity interpretation, multiple attenuation, increase in S/N ratio and improved stack response. This paper focuses on a Previous HitdataNext Hit driven approach that performs 3D cascaded adaptive filtering of aliased and dispersive Surface Waves at their true spatial coordinates (AGORA GR & GW) and will be described using both Narrow and Wide-Azimuth Previous HitlandNext Hit Previous HitdataTop examples.

Acknowledgements
We would like to thank Petroleum Development of Oman and CGGVeritas for their permission to publish this paper.

AAPG Search and Discovery Article #90105 © 2010 AAPG GEO Middle East Conference & Exhibition, Manama, Bahrain, 7-10 March 2010