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SURFACE WAVE ELIMINATION BY INTERFEROMETRY AND ADAPTIVE SUBTRACTION. YANWEI XUE University of Utah. Outline. Surface Wave Problem & Remedy Theory of Interferometric Filtering 2D Field Data Results 3D Field Data Results Conclusions. Problem: Surface waves blur the seismograms.
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SURFACE WAVE ELIMINATION BY INTERFEROMETRY AND ADAPTIVE SUBTRACTION YANWEI XUE University of Utah
Outline • Surface Wave Problem & Remedy • Theory of Interferometric Filtering • 2D Field Data Results • 3D Field Data Results • Conclusions
Problem: Surface waves blur the seismograms. A seismogram with surface waves and reflections Reflection waves 0 Time (s) Surface waves 2.0 Receiver (m) 0 7200 surf ref = d + d d Solution: Filter the surface waves by Non-Linear Filter (NLF) and interferometric method
Outline • Surface Wave Problem & Remedy • Theory of Interferometric Prediction • 2D Field Data Results • 3D Field Data Results • Conclusions
Near-OffsetSurf. Wave Mid-OffsetSurf. Wave Near-OffsetSurf. Wave A B A B B A A B A B B A B A Prediction of Surface Waves
Basic Strategy ^ s Input data d d Interferometric prediction ^ ^ ^ d s ^ ^ ^ Least squares subtraction r No Output data Yes Surface waves are removed completely?
0 Time (s) 2.0 Receiver (m) 0 3600 Nonlinear Local Filter
Outline • Surface Wave Problem & Remedy • Theory of Interferometric Filtering • 2D Field Data Results • 3D Field Data Results • Conclusions
0 Time (s) 2.0 Receiver (m) 0 3600 Raw Data
0 Time (s) 2.0 Receiver (m) 0 3600 Remove Surface Waves by NLF
0 Time (s) 2.0 Receiver (m) 0 3600 Remove Surface Waves by Int.+NLF
0 Time (s) 2.0 Receiver (m) 0 3600 Raw Data
0 Time (s) 2.0 Receiver (m) 0 3600 Remove Surface Waves by F-K
0 Time (s) 2.0 Receiver (m) 0 3600 Remove Surface Waves by Int.+NLF
0 Time (s) 2.0 Receiver (m) 0 3600 Surface Waves Predicted by F-K
0 Time (s) 2.0 Receiver (m) 0 3600 Surface Waves Predicted by Int.+NLF
Outline • Surface Wave Problem & Remedy • Theory of Interferometric Filtering • 2D Field Data Results • 3D Field Data Results • Conclusions
0 0 Time (s) Time (s) 4.0 4.0 0 0 Receiver(m) 5000 Receiver (m) 5000 Line 9 Before and After Removal of Surface Waves
0 0 Time (s) Time (s) 4.0 4.0 0 0 Receiver (m) 5000 Receiver (m) 5000 Line 11 Before and After Removal of Surface Waves
0 0 Time (s) Time (s) 4.0 4.0 0 0 Receiver (m) 5000 Receiver (m) 5000 Line 13 Before and After Removal of Surface Waves
0 0 Time (s) Time (s) 4.0 4.0 0 0 Receiver (m) 5000 Receiver (m) 5000 Line 14 Before and After Removal of Surface Waves
Outline • Surface Wave Problem & Remedy • Theory of Interferometric Filtering • 2D Field Data Results • 3D Field Data Results • Conclusions
Conclusions • This approach is effective for surface wave removal in both 2D and 3D cases. • Advantages: • Better than FK method for irregular acquisition geometry. • No need for a near surface velocity model. • Limitations: • Sensitive to the choice of NLF parameters. • Parameter selection can be expensive. • Future Work: • Eliminate need for non-linear local filter. • More tests on 3D data.
Acknowledgement I thank the sponsors of 2006 UTAM consortium for their financial support.