F-K Filtering of multiple reflections from a seismic section

Claim 1

A method of filtering multiple reflections from seismograms representing the earth's formations comprising: (a) generating first seismograms representing the amplitude of seismic primary and multiple reflections as a function of time and distance along a line of exploration; (b) transforming said first seismograms into an f-k array of first real and first imaginary parts representing amplitude as a function of frequency and wave number; (c) normal moveout correcting said first seismograms with the apparent velocity of said multiple reflections to align said multiple reflections; (d) stacking said normal moveout corrected first seismograms having aligned multiple reflections, (e) inverse normal moveout correcting said stacked first seismograms to produce second seismograms representing multiple reflections, (f) transforming said second seismograms with aligned multiple reflections into an f-k array of second real and second imaginary parts, (g) determining the inverse of said second real and second imaginary parts of the f-k array of said second seismograms, (h) filtering said first real part of the f-k array of said first seismograms by weighting all samples of said first real part with corresponding samples of the inverse of said second real part of the f-k array of said second seismograms, (i) filtering said first imaginary part of the f-k array of said first seismograms by weighting all samples of said first imaginary part with corresponding samples of the inverse of said second imaginary part of the f-k array of said second seismograms, and (j) transforming said filtered first real and first imaginary parts into third seismograms representing an enhanced representation of the earth's formation with suppressed multiple reflections as a function of time and distance along said line of exploration.

Claim 2

A method of filtering multiple reflections from seismograms representing the earth's formations comprising: (a) generating first seismograms representing the amplitude of seismic primary and multiple reflections as a function of time and distance along a line of exploration; (b) transforming said first seismograms into an f-k array of first real and first imaginary parts representing amplitude as a function of frequency and wave number; (c) normal moveout correcting said first seismograms with the apparent velocity of said multiple reflections to align said multiple reflections; (d) stacking said normal moveout corrected first seismograms having aligned multiple reflections, (e) inverse normal moveout correcting said stacked first seismograms to produce second seismograms representing multiple reflections, (f) transforming said second seismograms with aligned multiple reflections into an f-k array of second real and second imaginary parts, (g) determining the inverse of said second real and second imaginary parts of the f-k array of said second seismograms, (h) filtering said first real part of the f-k array of said first seismograms by weighting all samples of said first real part with corresponding samples of the inverse of said second real part of the f-k array of said second seismograms, (i) filtering said first imaginary part of the f-k array of said first seismograms by weighting all samples of said first imaginary part with corresponding samples of the inverse of said second imaginary part of the f-k array of said second seismograms, and (j) transforming said filtered first real and first imaginary parts into third seismograms representing an enhanced representation of the earth's formation with suppressed multiple reflections as a function of time and distance along said line of exploration.