Seismic Reflection Data Processing and Interpretation A Workshop in Cairo 28 Oct. 9 Nov. 2006 Cairo...
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Seismic Reflection Data Seismic Reflection Data Processing and Processing and Interpretation Interpretation A Workshop in Cairo A Workshop in Cairo 28 Oct. – 9 Nov. 2006 28 Oct. – 9 Nov. 2006 Cairo University, Egypt Cairo University, Egypt Dr. Sherif Mohamed Hanafy Lecturer Title: 1D & 2D Fourier Transform
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What would happen if; We increasingly added to a time signal higher frequency components? The resulted wavelet will be compressed, if all frequencies are added the result will be a spike.
Transcript of Seismic Reflection Data Processing and Interpretation A Workshop in Cairo 28 Oct. 9 Nov. 2006 Cairo...
Seismic Reflection Data Processing Seismic Reflection Data Processing and Interpretationand Interpretation
A Workshop in CairoA Workshop in Cairo28 Oct. – 9 Nov. 200628 Oct. – 9 Nov. 2006
Cairo University, EgyptCairo University, Egypt
Dr. Sherif Mohamed Hanafy
Lecturer Title:
1D & 2D Fourier Transform
1D & 2D Fourier 1D & 2D Fourier TransformTransform
(Continue)(Continue)Theory and PracticeTheory and Practice
Real Data Examples UsingReal Data Examples UsingSU and MatLabSU and MatLab
What would happen if;What would happen if;
We increasingly added to a time signal higher frequency components?
The resulted wavelet will be compressed, if all frequencies are added the result will be a spike.
With increasing the frequencies With increasing the frequencies summed to the signal; resulted trace is summed to the signal; resulted trace is
compressed.compressed.Note the effect on the stacked traces 1, Note the effect on the stacked traces 1,
2, 3, 4, & 52, 3, 4, & 5
Only two frequencies are summed
More than 30 different frequencies are summed
With a very high number of traces With a very high number of traces (frequency are continuously increased) (frequency are continuously increased)
the resulted stackedthe resulted stackedtrace is very sharp; almost a spike.trace is very sharp; almost a spike.
From the frequency spectrum point of From the frequency spectrum point of view, we can see the same feature; the view, we can see the same feature; the
wider the frequency band the sharper the wider the frequency band the sharper the related time trace.related time trace.
The effect of the edge of the The effect of the edge of the frequency spectrumfrequency spectrum
Smooth edges (A, B, C & D) and gentle slopes AB and CD give much improved results
Types of frequency filtersTypes of frequency filters
Band Pass
Band Reject
Low Pass
High Pass
Butterworth FilterButterworth Filter
The usable seismic reflection The usable seismic reflection energy usually is confined to a energy usually is confined to a bandwidth of approximately 10 bandwidth of approximately 10
– 70 Hz, with a dominant – 70 Hz, with a dominant frequency around 30 Hz.frequency around 30 Hz.
Application of frequency Application of frequency domain filtersdomain filters
Effect of Band Pass Effect of Band Pass Parameters on the resulted Parameters on the resulted
seismic sectionseismic sectionUse the data of Stockton Interferometry Use the data of Stockton Interferometry
test to show the effect of low and high test to show the effect of low and high cuts, fixing band width and slops.cuts, fixing band width and slops.
Low Cut
Low Pass
High Pass
High Cut
File # 1File # 1x17_f1.sux17_f1.su
Use: suximage< x17_f1.su n2=57 Use: suximage< x17_f1.su n2=57 perc=95 &perc=95 &
Low Cut = 10 to 110 Low Cut = 10 to 110 HzHzLow Pass = 25 to 125 Low Pass = 25 to 125 HzHzHigh Pass = 80 to High Pass = 80 to 180 Hz180 HzHigh Cut = 95 to 195 High Cut = 95 to 195 HzHzStep = 1 HzStep = 1 Hz
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File # 2File # 2x17_f2.sux17_f2.su
Use: suximage< x17_f2.su n2=57 Use: suximage< x17_f2.su n2=57 perc=95 &perc=95 &
Low Cut = 22 HzLow Cut = 22 HzLow Pass = 37 HzLow Pass = 37 HzHigh Pass = 47 to High Pass = 47 to 147 Hz147 HzHigh Cut = 52 to 152 High Cut = 52 to 152 HzHzStep = 1 HzStep = 1 Hz
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File # 3File # 3x17_f3.sux17_f3.su
Use: suximage< x17_f3.su n2=57 Use: suximage< x17_f3.su n2=57 perc=95 &perc=95 &
Low Cut = 36 to 4 HzLow Cut = 36 to 4 HzLow Pass = 37 HzLow Pass = 37 HzHigh Pass = 92 HzHigh Pass = 92 HzHigh Cut = 93 to 125 High Cut = 93 to 125 HzHzStep = 1 HzStep = 1 Hz
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End of this lectureEnd of this lecture
Thank You for you attentionThank You for you attention
All examples on this lecture is based on my workAll examples on this lecture is based on my work
