IP Library › Granted Patent US 12699195
Granted Patent B2
US 12699195 · App. 18/063,587 · Granted Aug 4, 2026

Seismic wavefield modeling honoring AVO/AVA with applications to full waveform inversion and least-squares imaging

Inventors: Timothy Burgess (Subiaco, AU); James McLeman (Subiaco, AU); Mrinal Sinha (East Perth, AU); Gary Hampson (Peppermint Grove, AU); Troy Thompson (Duncraig, AU)
Assignee: DUG Technology (Australia) Pty Ltd.
G01V1/282G01V1/303G01V1/306G01V1/32G01V2210/614G01V2210/6224G01V2210/632G01V2210/645
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Quick Facts
Patent No.
US 12699195
App. No.
18/063,587
Granted
Aug 4, 2026
Kind
B2
Abstract

A method for modelling and migrating seismic data, that includes using an acoustic wave equation and a spatial distribution of one or more earth-model parameters. The acoustic wave equation is modified by including at least one secondary source term, and based on a seismic acquisition configuration, either calculating the seismic signals that would be detected from the modelled wavefield or migrating observed seismic signals or migrating residual signals as part of an inversion.

Claims (60)

1 . A method for producing an image of spatial distribution of subsurface elastic wave propagation parameters for seismic exploration, comprising, in a computer:

calculating expected seismic signals based on an arrangement of at least one seismic source and at least one seismic receiver and based on an initial model of Earth's subsurface, the at least one seismic source and the at least one seismic receiver disposed proximate a volume of subsurface to be analyzed, the initial model comprising spatial distribution of at least one parameter related to propagation of elastic waves in subsurface formations in the volume, the calculating comprising entering the initial model into an acoustic wave equation modified by at least one secondary source term, the at least one secondary source term used to estimate amplitude versus offset and/or angle (AVO/A) phenomena in the calculated expected seismic signals, the acoustic wave equation requiring modification by the at least one secondary source term to perform the estimation;

comparing the calculated expected seismic signals with measured seismic signals from the at least one sensor obtained as a result of actuating the at least one seismic source;

determining differences between the calculated seismic signals and the measured seismic signals;

using an inversion method to adjust the initial model and repeating the calculating, comparing and determining until the differences fall below a selected difference limit to generate a final model of spatial distribution of the at least one parameter; and

using the final model to produce a seismic image of the subsurface.

2 . The method of claim 1 wherein the adjusting comprises changing at least one of a value of the at least one parameter and/or the spatial distribution.

3 . The method of claim 2 wherein the at least one secondary source term represents reflectivity.

4 . The method of claim 3 wherein the reflectivity results from changes in at the least one parameter.

5 . The method of claim 4 wherein the at least one parameter comprises compressional (P) wave velocity.

6 . The method of claim 4 wherein the at least one parameter comprises shear(S) wave velocity.

7 . The method of claim 4 wherein the at least one parameter comprises density.

8 . The method of claim 4 wherein the at least one parameter comprises compressional (P) wave impedance.

9 . The method of claim 4 wherein the at least one parameter comprises shear(S) wave impedance.

10 . The method of claim 4 wherein the at least one parameter comprises elastic impedance.

11 . The method of claim 4 wherein the at least one parameter comprises at least one component of an elastic tensor.

12 . The method of claim 4 wherein the at least one parameter comprises attenuation.

13 . The method of claim 4 further comprising producing a reflectivity image from the adjusted initial earth model.

14 . The method of claim 13 further comprising selectively modifying the at least one parameter and/or a strength of the at least one secondary source term in order to control production of diving wave-paths (bananas) and reflection wave-paths (rabbit ears) as substantially separate terms in a gradient of an objective function of a full waveform inversion.

15 . The method of claim 13 further comprising selectively modifying the at least one parameter and/or a strength of the at least one secondary source term in order to produce substantially only diving wave-paths (bananas) in a gradient of an objective function of a full waveform inversion.

16 . The method of claim 13 further comprising selectively modifying the at least one parameter and/or a strength of the at least one secondary source term in order to produce substantially only reflection wave-paths (rabbit ears) in a gradient of an objective function of a full waveform inversion.

17 . The method of claim 4 wherein the reflectivity is expressed as the grad of a spatially-variable scalar parameter field.

18 . The method of claim 1 wherein the at least one secondary source term estimates reflecting or scattering an incident wavefield with directional variations.

19 . The method of claim 1 wherein the at least one secondary source term estimates reflectivity corresponding to an AVO/A intercept attribute.

20 . The method of claim 1 wherein the at least one secondary source term comprises reflectivity corresponding to an AVO/A gradient attribute.

21 . The method of claim 1 wherein the at least one secondary source term comprises reflectivity corresponding to an AVO/A curvature attribute.

22 . The method of claim 1 further comprising injecting resulting secondary source terms into a different wavefield from that which their values depend on.

23 . The method of claim 1 further comprising Born modelling.

24 . The method of claim 1 wherein a termination criterion of the inversion method comprises a predetermined number of repetitions.

25 . The method of claim 1 wherein a termination criterion of the inversion comprises a predetermined similarity between the calculated seismic signals and the measured seismic signals.

26 . A computer program stored in a non-transitory computer readable medium, the program having logic operable to cause a programmable computer to perform a process for generating a subsurface image of elastic wave propagation property parameters for seismic exploration, the process comprising:

calculating expected seismic signals based on an arrangement of at least one seismic source and at least one seismic receiver and based on an initial model of Earth's subsurface, the at least one seismic source and the at least one seismic receiver disposed proximate a volume of subsurface to be analyzed, the initial model comprising spatial distribution of at least one parameter related to propagation of elastic waves in subsurface formations in the volume, the calculating comprising entering the initial model into an acoustic wave equation modified by at least one secondary source term, the at least one secondary source term used to estimate amplitude versus offset and/or angle (AVO/A) phenomena in the calculated expected seismic signals, the acoustic wave equation requiring modification by the at least one secondary source term to perform the estimation;

comparing the calculated expected seismic signals with measured seismic signals obtained from the at least one seismic sensor in response to actuating the at least one source;

determining differences between the calculated seismic signals and the measured seismic signals;

using an inversion method to adjust the initial model and repeating the calculating, comparing and determining until the differences fall below a selected difference limit to generate a final model of spatial distribution of the at least one parameter; and

generating an image of the spatial distribution of the at least one parameter using the final model.

27 . The computer program of claim 26 wherein the adjusting comprises changing at least one of a value of the at least one parameter and/or the spatial distribution.

28 . The computer program of claim 27 wherein the at least one secondary source term represents reflectivity.

29 . The computer program of claim 28 wherein the reflectivity results from changes in the at least one parameter.

30 . The computer program of claim 29 wherein the at least one parameter comprises compressional (P) wave velocity.

31 . The computer program of claim 29 wherein the at least one parameter comprises shear(S) wave velocity.

32 . The computer program of claim 29 wherein the at least one parameter comprises density.

33 . The computer program of claim 29 wherein the at least one parameter comprises compressional (P) wave impedance.

34 . The computer program of claim 29 wherein the at least one parameter comprises shear(S) wave impedance.

35 . The computer program of claim 29 wherein the at least one parameter comprises elastic impedance.

36 . The computer program of claim 29 wherein the at least one parameter comprises at least one component of an elastic tensor.

37 . The computer program of claim 29 wherein the at least one parameter comprises attenuation.

38 . The computer program of claim 29 wherein the logic is further operable to cause the computer to perform producing a reflectivity image from the adjusted initial earth model.

39 . The method of claim 38 wherein the reflectivity is expressed as the grad of a spatially-variable scalar parameter field.

40 . The computer program of claim 39 wherein the logic is further operable to cause the computer to perform selectively modifying the at least one parameter and/or a strength of the at least one secondary source term in order to control production of diving wave-paths (bananas) and reflection wave-paths (rabbit ears) as substantially separate terms in a gradient of an objective function of a full waveform inversion.

41 . The computer program of claim 39 wherein the logic is further operable to cause the computer to perform selectively modifying the at least parameter and/or a strength of the at least one secondary source term in order to substantially produce only diving wave-paths (bananas) in a gradient of an objective function of a full waveform inversion.

42 . The computer program of claim 39 wherein the logic is further operable to cause the computer to perform selectively modifying the at least one parameter and/or a strength of the at least one secondary source term in order to produce substantially only reflection wave-paths (rabbit ears) in a gradient of an objective function of a full waveform inversion.

43 . The computer program of claim 26 wherein the at least one secondary source term estimates reflecting or scattering an incident wavefield with directional variations.

44 . The computer program of claim 26 wherein the at least one secondary source term estimates reflectivity corresponding to an AVO/A intercept attribute.

45 . The computer program of claim 26 wherein the at least one secondary source term estimates reflectivity corresponding to an AVO/A gradient attribute.

46 . The computer program of claim 26 wherein the at least one secondary source term estimates reflectivity corresponding to an AVO/A curvature attribute.

47 . The computer program of claim 26 further comprising injecting resulting secondary source terms into a different wavefield from that which their values depend on.

48 . The computer program of claim 26 wherein the logic is further operable to cause the computer to perform Born modelling.

49 . The computer program of claim 26 wherein a termination criterion of the inversion comprises a predetermined number of repetitions.

50 . The computer program of claim 26 wherein a termination criterion of the inversion comprises a predetermined similarity between the calculated and measured signals.