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Seismic Reflection: Processing and Interpretation. Katie Wooddell UW Madison. Objectives. Develop a velocity model of the Santa Fe River Canyon to aid in structure interpretation Use predictive deconvolution to remove multiple reflections from the data . Processing Steps. Processing Steps.
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Seismic Reflection:Processing and Interpretation Katie Wooddell UW Madison
Objectives • Develop a velocity model of the Santa Fe River Canyon to aid in structure interpretation • Use predictive deconvolution to remove multiple reflections from the data
Killing Traces • Vibroseis signal had to be eliminated • Channels showing large amounts of noise were deleted
Predictive Deconvolution What does it do? Clears seismic data by predicting and eliminating multiple reflections How does it work? A filter is designed that recognizes and eliminates repetitions in the signal
Deconvolution Equation Robertson 1998
To Conceptualize. . . INPUT OUTPUT FILTER = *
Deconvolution Results Location 109 Location 109 Time (ms) Time (ms) NO DECONVOLUTION DECONVOLVED
Butterworth Filter • Bandpass Filter • Passes frequencies in the range of the vibroseis sweep (30-300 Hz) • Effective in eliminating the noise amplified during predictive deconvolution
Butterworth Filtering Location 109 Location 109 Time (ms) Time (ms) No Filter Butterworth Filter
NMO Correction • NMO corrects for the delay in first arrival times • NMO shifts the arrival times according to a specific stacking velocity • This is an important step in the velocity analysis
Velocity Analysis • A Constant Velocity Analysis was conducted on both deconvolved and non-deconvolved data • The following NMO stacking velocities were run for each situation: - 1000 m/s -1200 m/s - 1400 m/s -1600 m/s - 1800 m/s -2000 m/s - 2200 m/s -2400 m/s
Conclusions • Predictive deconvolution is an effective tool for eliminating multiples from seismic data • A combination of the 2000 m/s and the 1600 m/s constant velocity models seems to produce a high resolution model • This implies a higher average velocity medium on the east side of the fault, giving evidence that the normal La Bajada fault is being imaged
And a Special Thanks To. . . The SAGE professors for their knowledge and patience Team 5 for their hard work and some good times Michelle Herrera, my Processing partner Lauren Larkin, who was more enthusiastic about splicing together my seismic sections than I was