US 12,631,777 B2Granted

System and method for obtaining minimum-phase source-signatures from multi-channel multi-offset seismic data

AssigneeThe Board of Regents for the Oklahoma Agricultural and Mechanical Colleges

InventorsAfshin Aghayan, Priyank Jaiswal

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Abstract

According to one embodiment, a near-field data is used to determine a taper length that can isolate the source signature at the top of near-field data with minimum interaction with the Green's function. In some embodiments, a range of taper lengths is selected and for each length after tapering the near-filed data, converting each filtered near-field data to its minimum-phase equivalents. Summing pairwise cross-correlation of all of the minimum-phase equivalent wavelets at the zero-lag provides an attribute that shows how much the tapered portions of the near-field data look alike. An acceptable taper size will be the one that has the highest summation value. Finally, the average of the minimum-phase equivalents of tapered near-field data with the selected taper size is the estimated source signature.

Claims16

Dependent claims

A method of seismic data processing comprising the steps of:

(a) obtaining a source gather comprising a plurality of seismic traces, each of said traces being associated with a distance from a same seismic source, said source having a source signature associated therewith;
(b) using at least said associated distances to identify a plurality of near-field traces from within said source gather;
(c) determining a first break time associated with each of said plurality of near-field traces;
(d) using said determined first break times to align each of said plurality of near-field traces;
(e) selecting a taper;
(f) selecting a taper length;
(g) applying said taper and said selected taper length to each of said plurality of aligned near-field traces, thereby producing a same plurality of tapered aligned near-field traces;
(h) calculating a minimum-phase equivalent wavelet from each of said plurality of tapered aligned near-field wavelet estimates, thereby obtaining a plurality of minimum-phase equivalent wavelets;
(i) calculating a plurality of similarity values from among said plurality of minimum-phase equivalent wavelets;
(j) summing together said plurality of similarity values, thereby obtaining a quality value associated with the selected taper length;
(k) performing steps (f) through (j) for at least one other selected taper length, thereby obtaining a plurality of quality values, with each of said plurality of quality values being associated with one of said selected taper lengths;
(l) identifying a maximum value of said plurality of quality values and an identified taper length associated therewith;
(m) selecting said plurality of minimum-phase equivalent wavelets associated with said identified taper length;
(n) estimating said source signature using said selected plurality of minimum-phase equivalent wavelets;
and
(o) using said estimated source signature to process seismic data to obtain an improved subsurface image.

13 more elements

A method of seismic data processing comprising the steps of:

(a) obtaining a source gather comprising a plurality of seismic traces, each of said traces being associated with a distance from a same source, said source having a source signature;
(b) using at least said associated distances to identify a plurality of near-field traces from within said source gather;
(c) determining a first break time associated with each of said identified near-field traces, thereby obtaining a plurality of said first break times;
(d) using said plurality of first break times to align each of said near field traces;
(e) selecting a taper;
(f) selecting a taper length;
(g) using said selected taper and said selected taper length to filter each of said aligned near-field traces, thereby obtaining a plurality of wavelets;
(h) converting each of said plurality of wavelets to a minimum-phase equivalent wavelet;
(i) calculating a plurality of similarity values from among said plurality of minimum-phase equivalent wavelets;
(j) using said plurality of similarity values to obtain a quality value associated with said selected taper length;
(k) performing steps (f) through (j) for at least one other selected taper length, thereby obtaining a plurality of quality values, with each of said plurality of quality values being associated with one of said selected taper lengths;
(l) identifying a maximum value of said plurality of quality values and an identified taper length associated therewith;
(m) selecting said plurality of minimum-phase equivalent wavelets associated with said identified taper length;
(n) estimating said source signature using said selected plurality of minimum-phase equivalent wavelets;
and
(o) using said estimated source signature to process seismic data to obtain an improved subsurface image.

13 more elements

A computerized method of estimating a seismic source using software executing in a computer, said software performing at least the steps of:

(a) accessing a source gather comprising a plurality of seismic traces, each of said traces being associated with a distance from said same seismic source, said source having a source signature associated therewith;
(b) using at least said associated distances to identify a plurality of near-field traces from within said source gather;
(c) determining a first break time associated with each of said plurality of near-field traces;
(d) using said determined first break times to align each of said plurality of near-field traces;
(e) selecting a taper;
(f) selecting a taper length;
(g) applying said taper and said selected taper length to each of said plurality of aligned near-field traces, thereby producing a same plurality of tapered aligned near-field traces;
(h) calculating a minimum-phase equivalent wavelet from each of said plurality of tapered aligned near-field wavelet estimates, thereby obtaining a plurality of minimum-phase equivalent wavelets;
(i) calculating a plurality of similarity values from among said plurality of minimum-phase equivalent wavelets;
(j) summing together said plurality of similarity values, thereby obtaining a quality value associated with the selected taper length;
(k) performing steps (f) through (j) for at least one other selected taper length, thereby obtaining a plurality of quality values, with each of said plurality of quality values being associated with one of said selected taper lengths;
(l) identifying a maximum value of said plurality of quality values and an identified taper length associated therewith;
(m) selecting said plurality of minimum-phase equivalent wavelets associated with said identified taper length;
(n) estimating said source signature using said selected plurality of minimum-phase equivalent wavelets;
and
(o) using said estimated source signature to process seismic data to obtain an improved subsurface image.

13 more elements

Dependencies are inferred from the claim text.

Facts

Application: 18/034,428Filed 5 Nov 2021 · us provisional application
Priority: 6 Nov 2020
Published: US 2023/0393295 A17 Dec 2023
Granted: 19 May 2026
Term ends: Not estimatedThe source records don’t support an estimate.

Classification11 codes

G01V 1/307
Analysis: for determining seismic attributes, e.g. amplitude, instantaneous phase or frequency, reflection strength or polarity
G01V 1/366
Seismic filtering: by correlation of seismic signals
G01V 1/282
Processing seismic data, e.g. for interpretation or for event detection: application of seismic models, synthetic seismograms
G01V 1/003
Seismology; Seismic or acoustic prospecting or detecting: seismic data acquisition in general, e.g. survey design