US5392255A
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Wavelet transform method for downward continuation in seismic data migration
Assignee: Westerngeco LLC
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Filing: 1993-06-14
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Granted: 1995-02-21
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Expires: 2013-06-14
Abstract
Abstract A depth migration method for seismic data involves a depth migration in the omega-x domain with an added transform in the wavelet domain. The input to the migration is one spike at a given time and x position (or Common Depth Point). This is as if instead of using a collection of seismic traces as input to the processing sequence, traces are used which would be all null except one which contains a spike. The processing sequence involved for seismic traces is the same as the one involved for the spike (or impulse). The only difference is the input itself being the seismic trace rather than the impulse spike.
Inventors
- 👤 Ronan J. LeBras
- 👤 George R. Mellman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 02:22
CPC Classifications
G; G01; G01V; G01V1/00; G01V1/28; G01V1/30; G01V1/301
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
187 words
A method of processing seismic data including a collection of time/amplitude trace response functions located at least in one spatial dimension, and a velocity field function in another spatial dimension, to migrate said time/amplitude data into depth/amplitude data, comprising the steps of: (a) applying a wavelet transform to all frequency components of a velocity field downward continuation operator to define a downward continuation operator in the wavelet domain; (b) applying a wavelet transform of the spatial dimension to the collection of trace response functions, after the time/amplitude traces have been transformed through a standard fast Fourier transform method into transformed frequency/amplitude traces; (c) applying the operator obtained in step (a) for each frequency component to the transformed traces obtained in step, (b) to define a resultant collection of transformed traces in the wavelet domain for all desired depths; (d) applying the inverse wavelet transform on the spatial dimension, and defining the downward continued field in the spatial domain; (e) summing all frequency components at all depths to define the resulting depth/amplitude data; and (f) displaying the amplitude of the resultant depth/amplitude data as a function of depth.
Claim 2
Independent Claim
187 words
A method of processing seismic data including a collection of time/amplitude trace response functions located at least in one spatial dimension, and a velocity field function in another spatial dimension, to migrate said time/amplitude data into depth/amplitude data, comprising the steps of: (a) applying a wavelet transform to all frequency components of a velocity field downward continuation operator to define a downward continuation operator in the wavelet domain; (b) applying a wavelet transform of the spatial dimension to the collection of trace response functions, after the time/amplitude traces have been transformed through a standard fast Fourier transform method into transformed frequency/amplitude traces; (c) applying the operator obtained in step (a) for each frequency component to the transformed traces obtained in step, (b) to define a resultant collection of transformed traces in the wavelet domain for all desired depths; (d) applying the inverse wavelet transform on the spatial dimension, and defining the downward continued field in the spatial domain; (e) summing all frequency components at all depths to define the resulting depth/amplitude data; and (f) displaying the amplitude of the resultant depth/amplitude data as a function of depth.
Claim 3
Dependent Claim
17 words
The method of claim 1 wherein said trace response function comprises a Common Depth Point seismic gather.
Claim 4
Dependent Claim
17 words
The method of claim 1 wherein said trace response function comprises a set of stacked trace functions.
Claim 5
Dependent Claim
41 words
The method of claim 1 wherein the resultant collection of transformed traces defined in step (c) comprises data and further including the step of compressing the data by eliminating coefficients smaller than a preset percentage of the maximum of the spectrum.
Claim 6
Dependent Claim
28 words
The method of claim 4 further comprising the step of repeating the processing of the seismic data with a different preset percentage of the maximum of the spectrum.
Claim 7
Independent Claim
138 words
A method of processing seismic data at a plurality of frequencies including a collection of time/amplitude trace response functions and a velocity field function, to migrate said time/amplitude data into depth/amplitude data, comprising the steps of: a. computing the wavelet transform of downward continuation operators; b. taking the Fourier Transform of the time/amplitude trace response functions over time; c. for each frequency taking the wavelet transform of data down to a preset level; d. for each frequency and all depth steps, performing the downward continuation in the wavelet domain keeping at each depth step selected wavelet coefficients larger than a preset percentage of the maximum of all spectra; e. summing all frequency components at all depths in the wavelet domain; and f. taking the inverse wavelet transform of the wavelet domain image to get the spatial domain image.
Claim 8
Independent Claim
138 words
A method of processing seismic data at a plurality of frequencies including a collection of time/amplitude trace response functions and a velocity field function, to migrate said time/amplitude data into depth/amplitude data, comprising the steps of: a. computing the wavelet transform of downward continuation operators; b. taking the Fourier Transform of the time/amplitude trace response functions over time; c. for each frequency taking the wavelet transform of data down to a preset level; d. for each frequency and all depth steps, performing the downward continuation in the wavelet domain keeping at each depth step selected wavelet coefficients larger than a preset percentage of the maximum of all spectra; e. summing all frequency components at all depths in the wavelet domain; and f. taking the inverse wavelet transform of the wavelet domain image to get the spatial domain image.
Claim 9
Dependent Claim
17 words
The method of claim 6 wherein said trace response function comprises a Common Depth Point seismic gather.
Claim 10
Dependent Claim
17 words
The method of claim 6 wherein said trace response function comprises a set of stacked trace functions.
References Cited (Backward Citations)
US4766574A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-02-20 | 1998-08-22 | 1999-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-02-20 | 2002-08-22 | 2003-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-02-20 | 2006-08-22 | 2007-02-21 | $7700.00 | Window Closed / Lapsed |