Full-wavefield inversion of primaries and multiples in marine environment

Patent metadata

Field	Value
Publication number	US-9702998-B2
Application number	US-201414311045-A
Country	US
Kind code	B2
Filing date	Jun 20, 2014
Priority date	Jul 8, 2013
Publication date	Jul 11, 2017
Grant date	Jul 11, 2017

Abstract

Method for using the full wavefield (primaries, internal multiples and free-surface multiples) in inversion of marine seismic data, including both pressure and vertical velocity data ( 21 ), to infer a subsurface model of acoustic velocity or other physical property. The marine seismic data are separated ( 22 ) into up-going ( 23 ) and down-going ( 24 ) wavefields, and both wavefields are inverted in a joint manner, in which the final model is impacted by both wavefields. This may be achieved by inverting both wavefields simultaneously ( 25 ), or one after the other, i.e. in a cascaded approach ( 35→37 , or 45→47 ), for the subsurface properties ( 26, 38, 48 ).

First claim

The invention claimed is:

1. A computer-implemented method for inverting marine seismic data to infer a subsurface physical property model, said seismic data including pressure data and vertical velocity data, said method comprising:
separating the pressure data and the vertical velocity data into an up-going wavefield and a down-going wavefield;
inverting, with a full wavefield inversion, the up-going wavefield and the down-going wavefield together, either simultaneously or cascaded, to infer a subsurface physical property model; and
prospecting for hydrocarbons with the subsurface physical property model, wherein the separating and the inverting are performed using a computer.

2. The method of claim 1 , wherein the inversion is cascaded, the up-going wavefield being inverted first to infer an intermediate physical property model, then, using the intermediate physical property model as an initial model, the down-going wavefield is inverted to infer a final physical property model.

3. The method of claim 1 , wherein the inversion is cascaded, the down-going wavefield being inverted first to infer an intermediate physical property model, then, using the intermediate physical property model as an initial model, the up-going wavefield is inverted to infer a final physical property model.

4. The method of claim 1 , wherein the physical property is velocity or acoustic impedance.

5. The method of claim 1 , wherein the down-going wavefield is simulated in the inversion using mirror geometry.

6. A method of claim 1 , wherein the pressure and vertical velocity data are full wavefield data, not processed to eliminate or reduce multiple reflections.

7. The method of claim 1 , displaying an image of the subsurface generated from the subsurface physical property model.

8. The method of claim 1 , displaying an image of the subsurface generated from the final physical property model.

9. A computer-implemented method for inverting marine seismic data to infer a subsurface physical property model, said seismic data including pressure data and vertical velocity data, said method comprising:
separating the pressure data and the vertical velocity data into an up-going wavefield and a down-going wavefield; and
iteratively inverting, with a full wavefield inversion, the up-going wavefield and the down-going wavefield together, meaning that each iteration cycle inverts the up-going wavefield or the down-going wavefield or simultaneously inverts both up-going and down-going wavefields, with each iteration cycle resulting in a model update which is used to generate simulated data in a next iteration cycle, resulting finally in a final physical property model,
wherein the separating and the inverting are performed using a computer.

10. The method of claim 9 , wherein each inversion comprises using a current physical property model to simulate data, comparing the simulated data to corresponding actual data, measuring a degree of misfit, and using the misfit to generate an update to the current physical property model; wherein the up-going wavefield and the down-going wavefield are separately simulated.

11. The method of claim 10 , wherein the down-going wavefield is simulated using mirror geometry.

Assignees

• Bansal Reeshidev
• Baumstein Anatoly
• Routh Partha S
• Exxonmobil Upstream Res Co

Inventors

• Bansal Reeshidev
• Baumstein Anatoly
• Routh Partha S

Classifications

• G01V2210/1423

  Sea · CPC title

• G01V1/303 Primary

  for determining velocity profiles or travel times · CPC title