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Processing of the Field Data using Predictive Deconvolution
Yuqing Chen Aydar Zaripov Dias Urozayev King Abdullah University of Science and Technology 08/12/2015
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Outline 1) Experiment Description 2) Objective
3) Processing Methodology 4) Results and Interpretation 5) Conclusions
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Outline 1) Experiment Description 2) Objective
3) Processing Methodology 4) Results and Interpretation 5) Conclusions
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Area of Study Seismic profile AB is located along the road between the stadium and the construction site. B A Construction Construction
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Outline 1) Experiment Description 2) Objective
3) Processing Methodology 4) Results and Interpretation 5) Conclusions
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Objectives: Problem : noise (harmonic)
Solution : Use Prediction deconvolution to eliminate harmonic noise meanwhile compress wavelet (improve resolution)
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Outline 1) Experiment Description 2) Objective
3) Processing Methodology 4) Results and Interpretation 5) Conclusions
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Deconvolution Convolutional model (The forward problem):
x(t) – recorded seismogram w(t) – seismic wavelet r(t) – reflectivity Deconvolution (The inverse problem): e(t) – Earth’s impulse respoones
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Least Square Deconvolution
Minimize the misfit function! x(t) – Recorded seismogram a(t) – Filter y(t) – Actually output d(t) – Desired output
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Predictive Deconvolution
Noise attenuated Periodic event (multiple, harmonic noise) Prediction Filter 10
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Predictive Deconvolution
: Predicted time-advanced seismogram : Actual time-advanced seismogram x(t) : current and past seismogram a(t) : Predict Filter We can predict the predictable part of the seismogram like multiples and harmonic noise, etc.
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Outline 1) Experiment Description 2) Objective
3) Processing Methodology 4) Results and Interpretation 5) Conclusions
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Results and Interpretation
3 critical parameter in predictive deconvolution: (1) Predict length (2) Filter length (3) Whiten noise A cosine harmonic noise His autocorrelation map
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Results and Interpretation
Use the second maximum value of autocorrelation map.
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Results and Interpretation
Second maximum
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Results and Interpretation
Shot120 (Raw data)
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Results and Interpretation
Shot120 (After bandpass)
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Results and Interpretation
Shot120 (After PEF_Predict length: 30)
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Results and Interpretation
Shot120 (After PEF_Predict length: 2)
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Results and Interpretation
Shot120 (After PEF_Predict length: 60)
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Results and Interpretation
Shot 40 (After Bandpass)
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Results and Interpretation
Shot 40 (After PEF)
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Results and Interpretation
3 critical parameter in predictive deconvolution: (1) Predict length (2) Filter length (3) Whiten noise The filter length should at least longer than the predict length 2. We chose the filter length also from the spectrum. Seismic trace
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Results and Interpretation
50 200 100 300 150 400
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Results and Interpretation
3 critical parameter in predictive deconvolution: (1) Predict length (2) Filter length (3) Whiten noise Whitening 0.01%
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Results and Interpretation
3 critical parameter in predictive deconvolution: (1) Predict length (2) Filter length (3) Whiten noise Whitening 0.05%
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Conclusion Predictable noise is mitigated Improved temporal resolution
Minimum phase assumption Random reflectivity assumption High level of noise restricts the implementation
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Recommendations 2D predictive deconvolution
Compute different PEF’s for different segments of a seismogram Change seismogram to minimum phase before using PEF
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