Surveying techniques using multiple different types of sources

Patent metadata

Field	Value
Publication number	US-11899151-B2
Application number	US-201816213214-A
Country	US
Kind code	B2
Filing date	Dec 7, 2018
Priority date	Dec 18, 2017
Publication date	Feb 13, 2024
Grant date	Feb 13, 2024

Abstract

Techniques are disclosed relating to acquisition and imaging for marine surveys. In some embodiments, a transition survey that uses both one or more sources of a first type (e.g., impulsive sources) and one or more sources of a second type (e.g., vibratory sources) may facilitate calibration of prior surveys that use the first type of sources with subsequent surveys that use the second type of source. In some embodiments, the different types of sources may be operated simultaneously at approximately the same location. In some embodiments, signals generated by the sources are separated, e.g., using deconvolution. The signals may then be compared to generate difference information, which in turn may be used to adjust sensor measurements from a previous or subsequent survey. In various embodiments, the disclosed techniques may improve accuracy in images of geological formations and may facilitate transitions to new types of seismic sources while maintaining continuity in 4D surveys.

First claim

What is claimed is:

1. A method, comprising:
accessing, by a computing system, seismic data recorded using a plurality of seismic sensors during a transition survey, wherein the seismic data was recorded based on signals reflected from one or more geological structures in response to generating seismic signals using a first type of seismic source while also generating seismic signals using a second, different type of seismic source; and
adjusting, by the computing system based on the accessed seismic data from the transition survey, sensor signals from at least one of a prior seismic survey that used the first type of seismic source or a subsequent seismic survey that used the second type of seismic source, wherein the adjusting calibrates one of the prior and the subsequent surveys with the other;
wherein the transition survey comprised a 4D seismic survey relative to at least one of the prior seismic survey and the subsequent seismic survey, such that both the transition survey and the at least one survey employed seismic sensors spaced apart in an inline direction and in a crossline direction, and such that an elapsed time between the transition survey and the at least one survey was sufficiently long to allow detectable changes to occur in the geological structures between a time of the transition survey and a time of the at least one survey.

2. The method of claim 1 , wherein the first type of seismic source is an impulsive source and the second type of seismic source is a vibratory source.

3. The method of claim 1 , wherein the first type of seismic source is a vibratory source and the second type of seismic source is an impulsive source.

4. The method of claim 1 , wherein the first type of seismic source is a first type of impulsive source and the second type of seismic source is a second, different type of impulsive source.

5. The method of claim 1 , wherein the first type of seismic source is a first type of vibratory source and the second type of source is a second, different type of vibratory source.

6. The method of claim 1 , further comprising:
separating signals generated by the first type of seismic source from signals generated by the second type of seismic source;
generating difference information indicating differences between signals from the first type of seismic source and signals from the second type of seismic source; and
using the difference information to perform the adjusting.

7. The method of claim 6 , wherein the separating is based on a known modulation of the second type of seismic source.

8. The method of claim 7 , wherein the separating is performed by deconvolving the recorded signals with a signal used to modulate the second type of seismic source.

9. The method of claim 6 , wherein the generating the difference information includes autocorrelating the reflected signal generated by the second type of seismic source with a signal used to modulate the second type of seismic source and comparing a result of the autocorrelation with the reflected signal generated by the first type of seismic source.

10. The method of claim 6 , further comprising:
generating a first image of the one or more geological structures based on signals generated by the second type of seismic source; and
generating a second image of the one or more geological structures based on signals generated by the first type of seismic source;
wherein the generating the difference information is based on differences between the first image and the second image.

11. The method of claim 1 , wherein the generating seismic signals using the first type of seismic source and the generating seismic signals using the second type of seismic source were performed at a location of generating seismic signals using the first type of seismic source in the prior survey, wherein the prior survey did not use any seismic sources of the second type.

12. The method of claim 1 , further comprising performing the transition survey, including:
towing, in a body of water, the first type of seismic source and the second type of seismic source;
generating the seismic signals using the first type of seismic source while also generating the seismic signals using the second type of seismic source; and
recording the seismic data using the plurality of seismic sensors.

13. The method of claim 1 , wherein:
the elapsed time between the transition survey and the at least one survey was at least one month.

14. The method of claim 1 , wherein:
the elapsed time between the transition survey and the at least one survey was at least one year.

15. A system, comprising:
one or more processors; and
one or more memories having instructions stored thereon that are executable by the one or more processors to:
access seismic data recorded using a plurality of seismic sensors during a transition survey, wherein the seismic data was recorded based on signals reflected from one or more geological structures in response to generating seismic signals using a first type of seismic source while also generating seismic signals using a second, different type of seismic source; and
adjust, based on the accessed seismic data from the transition survey, sensor signals from at least one of a prior seismic survey that used the first type of seismic source or a subsequent seismic survey that used the second type of seismic source, wherein the adjustment calibrates one of the prior and the subsequent surveys with the other;

wherein the transition survey comprised a 4D seismic survey relative to at least one of the prior seismic survey and the subsequent seismic survey, such that both the transition survey and the at least one survey employed seismic sensors spaced apart in an inline direction and in a crossline direction, and such that an elapsed time between the transition survey and the at least one survey was sufficiently long to allow detectable changes to occur in the geological structures between a time of the transition survey and a time of the at least one survey.

16. The system of claim 15 , wherein the first type of seismic source is an impulsive source and the second type of seismic source is a vibratory source.

17. The system of claim 15 , wherein the first type of seismic source is a first type of impulsive source and the second type of seismic source is a second, different type of impulsive source.

18. The system of claim 15 , wherein the system is further configured to:
separate signals generated by the first type of seismic source from signals generated by the second type of seismic source;
generate difference information indicating differences between signals from the first type of seismic source and signals from the second type of seismic source; and
use the difference information to perform the adjustment.

19. The system of claim 18 , wherein the separation is performed based on a known modulation of the second type of seismic source.

20. The system of claim 18 , wherein, to generate the difference information, the system is configured to autocorrelate the reflected signal generated by the second type of seismic source with a signal used to modulate the second type of seismic source and compare a result of the autocorrelation with the reflected signal generated by the first type of seismic source.

21. The system of claim 15 , further comprising:
the first type of seismic source;
the second type of seismic source;
the plurality of seismic sensors; and
control equipment configured to performing the transition survey

Assignees

• Pgs Geophysical As

Inventors

• Hodges Edwin
• Beitz Manuel

Classifications

• G01V1/32

  Transforming one recording into another {or one representation into another} · CPC title

• G01V1/3808 Primary

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

• G01V1/308 Primary

  Time lapse or 4D effects, e.g. production related effects to the formation (fluid flow per se E21B47/00) · CPC title

• G01V2210/121

  Active source · CPC title

• G01V2210/127

  Cooperating multiple sources · CPC title