Wavefield regularization by 3-D wavefield decomposition for geophysical data

Patent metadata

Field	Value
Publication number	US-9322944-B2
Application number	US-201313900207-A
Country	US
Kind code	B2
Filing date	May 22, 2013
Priority date	Mar 15, 2013
Publication date	Apr 26, 2016
Grant date	Apr 26, 2016

Abstract

One embodiment relates to a method of wavefield regularization for geophysical data acquisition of seismic geophysical data. Measured traces, are obtained from an array of sensors. For each grid point on a processing grid, best-fitting traces of the measured traces are found. Using the best-fitting traces, spectral amplitudes of down-going and up-going wavefields are computed. The down-going and up-going wavefields are subsequently transformed to an output grid in a space-time domain. Another embodiment relates to an apparatus for wavefield regularization of geophysical data acquisition. Other embodiments, aspects and features are also disclosed.

First claim

What is claimed is:

1. A method of geophysical data acquisition and processing, the method comprising:
measuring seismic traces using a seismic source and an array of sensors to perform a seismic survey;
determining, for each grid point on the processing grid, a desired trace on a surface which corresponds to the array of sensors;
finding, for each grid point on a processing grid, best-fitting traces of the seismic traces, wherein finding the best-fitting traces comprises minimizing a weighted sum of differences that includes differences in common mid-point distances between the best-fitting traces and the desired traces;
computing spectral amplitudes of down-going and up-going wavefields using the best-fitting traces;
transforming the down-going and up-going wavefields to an output grid in a space-time domain; and
processing said wavefields transformed to the output grid to infer structures of earth formations below locations at which the seismic survey is performed.

2. The method of claim 1 , wherein the array of sensors is towed during the acquisition.

3. The method of claim 1 , wherein the sensors are multi-component
sensors that measure both pressure and particle velocities.

4. The method of claim 1 , wherein the common mid point distances are in the in-line and cross-line directions.

5. The method of claim 4 , wherein the weighted sum of differences further includes a difference in offsets between the best-fitting traces and the desired traces.

6. The method of claim 1 further comprising:
applying differential move-outs to the best-fitting traces to obtain offset-corrected traces.

7. The method of claim 6 further comprising:
applying dip-based correction to the offset-corrected traces to obtain azimuth-corrected traces.

8. An apparatus for acquisition and processing of geophysical data, the apparatus comprising:
a seismic source for imparting seismic energy into subterranean material formations;
an array of sensors for generating signals in response to the seismic energy;
a recording system for recording the signals generated by the array of sensors; and
a computer apparatus comprising:
memory configured to store processor-executable code and data;
a processor configured to execute the computer-readable code so as to modify the data;
computer-readable code for obtaining measured traces, the measured traces including traces measured using the seismic source and the array of sensors and recorded using the recording system;
computer-readable code for determining, for each grid point on a processing grid, a desired trace on a surface which corresponds to the array of sensors;
computer-readable code for finding, for each grid point on the processing grid, best-fitting traces of the measured traces;
computer-readable code for computing spectral amplitudes of down-going and up-going wavefields using the best-fitting traces, wherein finding the best-fitting traces comprises minimizing a weighted sum of differences that includes differences in common mid-point distances between the best-fitting traces and the desired traces; and
computer-readable code for transforming the down-going and up-going wavefields to an output grid in a space-time domain.

9. The apparatus of claim 8 , wherein the array of sensors comprise multi-component sensors that measure pressure and particle velocities.

10. The apparatus of claim 8 , wherein the common mid point distances are in the in-line and cross-line directions.

11. The apparatus of claim 10 , wherein the weighted sum of differences further includes a difference in offsets.

12. The apparatus of claim 8 further comprising:
computer-readable code for applying differential move-outs to the best-fitting traces to obtain offset-corrected traces.

13. The apparatus of claim 12 further comprising:
computer-readable code for applying dip-based correction to the offset-corrected traces to obtain azimuth-corrected traces.

14. A method of generating a geophysical data product, the method comprising:
obtaining seismic traces measured using a seismic source and an array of sensors;
determining, for each grid point on a processing grid, a desired trace on a surface which corresponds to the plurality of sensors;
finding, for each grid point on the processing grid, best-fitting traces of the seismic traces, wherein finding the best-fitting traces comprises minimizing a weighted sum of differences that includes differences in common mid-point distances between the best-fitting traces and the desired traces;
computing spectral amplitudes of down-going and up-going wavefields using the best-fitting traces;
transforming the down-going and up-going wavefields to an output grid in a space-time domain; and
storing said wavefields transformed to the putput grid in the geophysical data product for use in determining subsurface rock formation structures.

15. The method of claim 14 , wherein the common mid point distances are in the in-line and cross-line directions.

16. The method of claim 15 , wherein the weighted sum of differences further includes a difference in offsets.

Assignees

• Pgs Geophysical As

Inventors

• Van Borselen Roald G
• Hegge Robertus F

Classifications

• G01V2210/57

  Trace interpolation or extrapolation, e.g. for virtual receiver; Anti-aliasing for missing receivers · CPC title

• G01V1/307 Primary

  for determining seismic attributes, e.g. amplitude, instantaneous phase or frequency, reflection strength or polarity · CPC title

• G01V1/325 Primary

  Transforming one representation into another · CPC title