Method for synchronization of systems for seismic surveys, together with applications of the method

• US 5,548,562 A
• Filed: 05/10/1993
• Issued: 08/20/1996
• Est. Priority Date: 06/30/1992
• Status: Expired due to Term

• Current Assignee: GECO AS (Schlumberger NV)
• Original Assignee: GECO AS (Schlumberger NV)
• Inventors: Bragstad, Helge, Helgerud, Per
• Primary Examiner(s): Moskowitz, Nelson
• Application Number:
  US08/058,204
• Time in Patent Office: 1,198 Days
• Field of Search: 367/14, 367/19, 367/50, 367/55, 181/107
• US Class Current: 367/14
• CPC Class Codes: G01S 19/14 specially adapted for specific applications
• CPC Class Codes: G01V 1/26 Reference-signal-transmitting devices, e.g. indicating moment of firing of shot

Abstract

A method for the synchronization of systems for seismic surveys, wherein the systems are composed of subsystems and may be land-based or marine, consists in the survey system being supplied with an absolute time standard and in a time code based on the absolute time standard being generated in the survey system. There is further provided at least one programmable event generator in the survey system and this is synchronized with the absolute time standard. The time for a specific event is predetermined on the basis of given parameters and supplied with the time code which corresponds to this time. The time for a determined event is then supplied to the subsystems which are also provided with the absolute time standard. The event can thereby be executed in one or more of the subsystems on the basis of the supplied absolute time standard and a synchronization is obtained with the desired accuracy. The method can further be used for synchronizing shot times in a seismic signal generating system, and synchronizing the shot recording time and sampling times in a seismic data recording system. The method can also be used for determining the exact time of actually occurring events in a system for seismic surveys.

Claims

1. A method for synchronization of systems for seismic surveys and of subsystems of said systems, said systems being selected from the group consisting of land-based systems, marine-based systems, and a combination thereof, and said subsystems being selected from the group consisting of at least one navigation system, at least one seismic signal generating system and at least one recording system comprising:

supplying a survey system with an absolute time standard;

generating via a time code generator in said survey system a time code based on said absolute time standard;

providing at least one programmable event generator in said survey system;

connecting said event generator with said time code generator;

synchronizing said event generator with said absolute time standard;

predetermining the time for a defined event on the basis of given parameters;

providing the time for a defined event with said time code corresponding to a point in time;

supplying the time for said defined event to the respective subsystems;

continuously supplying said subsystems with said absolute time standard; and

executing said defined event in at least one respective subsystem on the basis of said continuously supplied absolute time standard.

2. The method as claimed in claim 1, and further comprising:

generating said time code in said time code generator on the basis of Universal Time Coordinated (UTC) absolute time standard; and

supplying a time signal to said time code generator for said UTC from a satellite navigation system.

3. The method as claimed in claim 2 and further comprising:

generating an Inter-Range Instrumentation Group time code (IRIG time code) by said time code generator.

4. The method as claimed in claim 3 and further comprising:

connecting said time code generator with at least one programmable event generator in each subsystem.

5. The method as claimed in claim 2 and further comprising:

synchronizing said programmable event generator on the basis of said (UTC) absolute time standard by supplying said code by said time code generator.

6. The method as claimed in claim 5 and further comprising:

supplying said predetermined time for said defined event to a programmable event generator in a respective subsystem.

7. The method as claimed in claim 6 and further comprising:

supplying said programmable event generator with said time code for said absolute time standard.

8. The method as claimed in claim 7 and further comprising:

initiating said defined event by said programmable event generator on the basis of said predetermined time and in synchronization with real time as indicated by said continuously supplied time code.

9. The method as claimed in claim 8 and further comprising:

connecting said programmable event generator and said time code generator with said satellite navigation system.

10. The method as claimed in claim 9 and further comprising:

generating said parameters for predetermining said time for said defined event on the basis of continuous position finding in said navigation system.

11. The method comprising:

applying said method as claimed in claim 1 for calculation and synchronization of shot time in a seismic signal generating system.

12. The method comprising:

applying said method as claimed in claim 1 for calculation and synchronization of shot recording time in a seismic data recording system.

13. The method comprising:

applying said method as claimed in claim 1 for calculation and synchronization of sampling times in a seismic data recording system.

14. The method comprising:

applying said method as claimed in claim 1 for determination of the precise point of time in absolute time for an actually occurring event.

15. The method as claimed in claim 2 wherein:

said satellite navigation system comprises a global positioning system (GPS).

16. The method as claimed in claim 15 and further comprising:

synchronizing said programmable event generator on the basis of said (UTC) absolute time standard by supplying said code directly via said GPS.

17. The method as claimed in claim 15 and further comprising:

supplying said predetermined time for said defined event to a programmable event generator in a respective subsystem.

18. The method as claimed in claim 17 and further comprising:

supplying said programmable event generator with said time code for said absolute time standard.

19. The method comprising:

applying said method as claimed in claim 10 for calculation and synchronization of shot time in a seismic signal generating system.

20. The method comprising:

applying said method as claimed in claim 10 for calculation and synchronization of shot recording time in a seismic data recording system.

21. The method comprising:

applying said method as claimed in claim 2 for calculation and synchronization of shot time in a seismic signal generating system.

22. The method comprising:

applying said method as claimed in claim 2 for calculation and synchronization of shot recording time in a seismic data recording system.

23. The method comprising:

applying said method as claimed in claim 2 for calculation and synchronization of sampling times in a seismic data recording system.

24. The method comprising:

applying said method as claimed in claim 2 for determination of the precise point of time in absolute time for an actually occurring event.

25. The method comprising:

applying said method as claimed in claim 3 for calculation and synchronization of shot time in a seismic signal generating system.

26. The method comprising:

applying said method as claimed in claim 3 for calculation and synchronization of shot recording time in a seismic data recording system.

27. The method comprising:

applying said method as claimed in claim 3 for calculation and synchronization of sampling times in a seismic data recording system.

28. The method comprising:

applying said method as claimed in claim 3 for determination of the precise point of time in absolute time for an actually occurring event.

29. The method comprising:

applying said method as claimed in claim 4 for calculation and synchronization of shot time in a seismic signal generating system.

30. The method comprising:

applying said method as claimed in claim 4 for calculation and synchronization of shot recording time in a seismic data recording system.

31. The method comprising:

applying said method as claimed in claim 4 for calculation and synchronization of sampling times in a seismic data recording system.

32. The method comprising:

applying said method as claimed in claim 4 for determination of the precise point of time in absolute time for an actually occurring event.

33. The method comprising:

applying said method as claimed in claim 5 for calculation and synchronization of shot time in a seismic signal generating system.

34. The method comprising:

applying said method as claimed in claim 5 for calculation and synchronization of shot recording time in a seismic data recording system.

35. The method comprising:

applying said method as claimed in claim 5 for calculation and synchronization of sampling times in a seismic data recording system.

36. The method comprising:

applying said method as claimed in claim 5 for determination of the precise point of time in absolute time for an actually occurring event.

37. The method comprising:

applying said method as claimed in claim 6 for calculation and synchronization of shot time in a seismic signal generating system.

38. The method comprising:

applying said method as claimed in claim 6 for calculation and synchronization of shot recording time in a seismic data recording system.

39. The method comprising:

applying said method as claimed in claim 6 for calculation and synchronization of sampling times in a seismic data recording system.

40. The method comprising:

applying said method as claimed in claim 6 for determination of the precise point of time in absolute time for an actually occurring event.

41. The method comprising:

applying said method as claimed in claim 7 for calculation and synchronization of shot time in a seismic signal generating system.

42. The method comprising:

applying said method as claimed in claim 7 for calculation and synchronization of shot recording time in a seismic data recording system.

43. The method comprising:

applying said method as claimed in claim 7 for calculation and synchronization of sampling times in a seismic data recording system.

44. The method comprising:

applying said method as claimed in claim 7 for determination of the precise point of time in absolute time for an actually occurring event.

45. The method comprising:

applying said method as claimed in claim 8 for calculation and synchronization of shot time in a seismic signal generating system.

46. The method comprising:

applying said method as claimed in claim 8 for calculation and synchronization of shot recording time in a seismic data recording system.

47. The method comprising:

applying said method as claimed in claim 8 for calculation and synchronization of sampling times in a seismic data recording system.

48. The method comprising:

applying said method as claimed in claim 8 for determination of the precise point of time in absolute time for an actually occurring event.

49. The method comprising:

applying said method as claimed in claim 9 for calculation and synchronization of shot time in a seismic signal generating system.

50. The method comprising:

applying said method as claimed in claim 9 for calculation and synchronization of shot recording time in a seismic data recording system.

51. The method comprising:

applying said method as claimed in claim 9 for calculation and synchronization of sampling times in a seismic data recording system.

52. The method comprising:

applying said method as claimed in claim 9 for determination of the precise point of time in absolute time for an actually occurring event.

53. The method comprising:

applying said method as claimed in claim 10 for calculation and synchronization of sampling times in a seismic data recording system.

54. The method comprising:

applying said method as claimed in claim 10 for determination of the precise point of time in absolute time for an actually occurring event.