Geophysical survey techniques using different correlation intervals

Patent metadata

Field	Value
Publication number	US-11294083-B2
Application number	US-201816055943-A
Country	US
Kind code	B2
Filing date	Aug 6, 2018
Priority date	Aug 16, 2017
Publication date	Apr 5, 2022
Grant date	Apr 5, 2022

Abstract

Techniques are disclosed relating to geophysical surveying. In various embodiments, a computer system may access seismic data for a geological formation, where the seismic data is recorded, using one or more sensors, during a seismic survey in which a first vibratory source was driven using a first digital code for at least a first time interval. The first digital code, in some embodiments, may include a first plurality of subsections corresponding to portions of the first time interval. In some embodiments, the computer system may image a first location of the geological formation using a correlation of only a first sub-section of the first plurality of sub-sections with the seismic data. Further, in some embodiments, the computer system may image a second location of the geological formation using a correlation of two or more of the first plurality of sub-sections with the seismic data.

First claim

What is claimed is:

1. A method, comprising:
accessing, by a computer system, seismic data for a geological formation, wherein the seismic data were recorded, using one or more sensors, during a seismic survey in which a first vibratory source, of a plurality of vibratory sources, was driven using a first digital code for at least a first time interval, wherein the first digital code includes a first plurality of sub-sections corresponding to portions of the first time interval;
imaging, by the computer system, a first location of the geological formation using a correlation of only a first sub-section of the first plurality of sub-sections with the seismic data; and
imaging, by the computer system, a second location of the geological formation using a correlation of two or more of the first plurality of sub-sections with the seismic data.

2. The method of claim 1 , further comprising:
imaging, by the computer system, a third location of the geological formation using a correlation of only a second sub-section of the first plurality of sub-sections with the seismic data; wherein the second location is at a second depth that is greater than first and third depths associated with the first and third locations, respectively.

3. The method of claim 1 , wherein the imaging the first location generates first imaging data with a first spatial resolution and a first signal-to-noise ratio; and wherein the imaging the second location generates second imaging data with a second spatial resolution that is lower than the first spatial resolution and a second signal-to-noise ratio that is greater than the first signal-to-noise ratio.

4. The method of claim 1 , further comprising:
imaging, by the computer system, a third location of the geological formation using a correlation of an entirety of the first digital code with the seismic data, wherein the third location is at a third depth that is greater than first and second depths associated with the first and second locations, respectively.

5. The method of claim 1 , wherein, during the seismic survey, a second vibratory source of the plurality of vibratory sources was driven using a second digital code during the first time interval, wherein the second digital code includes a second plurality of sub-sections; and wherein, during time intervals corresponding in length to the sub-sections in the first time interval, ones of the second plurality of sub-sections are uncorrelated, to at least a threshold degree, relative to ones of the first plurality of sub-sections.

6. The method of claim 1 , wherein imaging the first and second locations uses different respective first and second sensors of the one or more sensors.

7. The method of claim 1 , wherein each of the first plurality of sub-sections is a Gold code.

8. The method of claim 1 , wherein the first digital code is a Gold code.

9. The method of claim 1 :
wherein, during the seismic survey, the first vibratory source was subsequently driven using a second digital code for at least a second time interval; and
wherein the method further comprises imaging, by the computer system, a third location of the geological formation using a correlation of a combination of the first and second digital codes with the seismic data.

10. A non-transitory, computer-readable medium having instructions stored thereon that are executable by a computer system to perform operations comprising:
accessing, by the computer system, seismic data for a geological formation, wherein the seismic data were recorded, using one or more sensors, during a seismic survey in which a first vibratory source, of a plurality of vibratory sources, was driven using a first digital code for at least a first time interval, wherein the first digital code includes a first plurality of sub-sections corresponding to portions of the first time interval;
imaging, by the computer system, a first location of the geological formation using a correlation of only one of the first plurality of sub-sections with the seismic data; and
imaging, by the computer system, a second location of the geological formation using a correlation of two or more of the first plurality of sub-sections with the seismic data.

11. The non-transitory, computer-readable medium of claim 10 , wherein the first location is at a first depth of the geological formation; and wherein the second location is at a second depth of the geological formation that is greater than the first depth.

12. The non-transitory, computer-readable medium of claim 10 , wherein the imaging the first location generates first imaging data with a first spatial resolution and a first signal-to-noise ratio; and wherein the imaging the second location generates second imaging data with a second spatial resolution that is lower than the first spatial resolution and a second signal-to-noise ratio that is greater than the first signal-to-noise ratio.

13. The non-transitory, computer-readable medium of claim 10 , wherein, during the seismic survey, a second vibratory source of the plurality of vibratory sources was driven using a second digital code during the first time interval, wherein the second digital code includes a second plurality of sub-sections; and wherein, during time intervals corresponding in length to the sub-sections in the first time interval, ones of the second plurality of sub-sections are uncorrelated, to at least a threshold degree, relative to ones of the first plurality of sub-sections.

14. The non-transitory, computer-readable medium of claim 13 , wherein ones of the first plurality of sub-sections are uncorrelated, to at least a threshold degree, relative to other sub-sections of the first plurality of sub-sections.

15. The non-transitory, computer-readable medium of claim 10 , further comprising:
imaging, by the computer system, a third location of the geological formation using a correlation of an entirety of the first digital code with the seismic data.

16. The non-transitory, computer-readable medium of claim 10 , further comprising:
imaging, by the computer system, a fourth location of the geological formation using a correlation of a portion of one of the first plurality of sub-sections with the seismic data.

17. A method of manufacturing a geophysical data product, the method comprising:
towing a plurality of streamers that each include a plurality of seismic sensors;
towing at least a first vibratory source;
driving the first vibratory source during a first time interval, wherein the driving includes driving the first vibratory source using a first digital code that includes a first plurality of sub-sections corresponding to portions of the first time interval;
recording, during the first time interval using the plurality of seismic sensors, seismic data;
generating results based on the seismic data by performing processing steps including:
in relation to a first location of a geological formation, correlating only one of the first plurality of sub-sections with the seismic data; and
in relation to a second location of the geological formation, correlating two or more of the first plurality of sub-sections with the seismic data; and
storing the results, or data generated based on the results, in a tangible computer-readable medium, thereby completing the manufacture of the geophysical data product.

18. The method of claim 17 , further comprising:
driving a second vibratory source using a second digital code that includes a second plurality of sub-sections, wherein ones of the second plurality of sub-sections are uncorrelated to at leas

Assignees

• Pgs Geophysical As

Inventors

• Tenghamn Stig Rune Lennart
• Beitz Manuel
• Strand Christian

Classifications

• G01V1/3861

  control of source arrays, e.g. for far field control · CPC title

• G01V2210/1293

  Sea · CPC title

• G01V2210/1423

  Sea · CPC title

• G01V1/307

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

• G01V1/3808 Primary

  Seismic data acquisition, e.g. survey design · CPC title