Seismic data acquisition system

• US 20020193947A1
• Filed: 06/04/2002
• Published: 12/19/2002
• Est. Priority Date: 06/05/2001
• Status: Active Grant

• Current Assignee: Inova Systems
• Original Assignee: GeoSystems LLC
• Inventors: Chamberlain, Donald G.
• Granted Patent: US 6,977,867 B2
• Time in Patent Office: Days
• US Class Current: 702/16
• CPC Class Codes: G01V 1/003 Seismic data acquisition in general, e.g. survey design G01V1/3808, G01V1/42 take precedence
• CPC Class Codes: G01V 1/22 Transmitting seismic signals to recording or processing apparatus

Abstract

A seismic survey system having remote acquisition modules (RAMs) for acquiring seismic signals and communicating with a central recording system (CRU) via a network of cables, other RAMs, and line tap units (LTUs), arranged in a matrix of receiver lines and base lines. Each RAM cyclically converts analog signal values to digital, forming data packets. Interrogation commands emanating from the CRU and relayed with strategic delays by intervening LTUs and RAMs are received by the RAM. Each command causes the RAM to transmit a data packet. Strategic delays are set such that the transmission capacity of the line is best utilized. Power and frequency of transmission are selectable by the CRU to optimize performance. Cables contain multiple communication pairs. The network path between the RAM and the CRU is established from the CRU and altered in event of malfunction. All types of network elements are interconnectable. Recorded samples are synchronous.

Claims

1. A method of recording seismic survey data comprising the steps of:

a. Generating a terrestrially transmitted seismic survey event;

b. Detecting seismic reflections of said event by a plurality of physically spaced sensors;

c. Generating by said sensors, respective sensor signals corresponding to said seismic reflections;

d. Transmitting said sensor signals along a plurality of first and second signal channels to respective first and second signal processing modules; and

,

e. Transmitting first and second digital signals corresponding to said seismic reflections by said first and second signal processing modules to a signal recording system, said packets being transmitted by said first and second signal processing modules at a frequency selected from a spectrum that is variable as a function of the physical properties of a digital signal carrier between said first and second signal processing modules.

2. A method as described by claim 1 wherein said digital signals are transmitted in data packets, each packet comprising a finite number of digital data bits, said packets being transmitted by said first and second signal processing modules.

3. A method as described by claim 1 wherein cable of various characteristics may be selected for said digital signal carrier.

4. A method as described by claim 1 wherein the digital signal carrier is a modulated radio wave.

5. A method as described by claim 1 wherein the digital signal carrier is a modulated light wave.

6. A method as described by claim 1 wherein said first signal channels are transmitted by signal carrier cable between said first and second signal processing modules.

7. A method as described by claim 1 wherein said digital signals are transmitted along a receiver line to a digital signal processing module for retransmission along a base line to said signal recording system.

8. A method as described by claim 7 wherein the digital signals transmitted along a receiver line are transmitted at a transmission rate of substantially the same rate as the transmission rate along said base line.

9. A method as described by claim 7 wherein the digital signals transmitted along a receiver line are transmitted at a transmission rate that is substantially different from a transmission rate for digital signals transmitted along said base line.

10. A method as described by claim 2 wherein said finite number of data bits in a packet is variable.

11. A method as described by claim 1 wherein the plurality of first signal channels is variable.

14. A method of processing seismic data signals as described by claim 13 wherein said first data signal is carried by the same conduit that carries said first interrogation signal.

15. A method of processing seismic data signals as described by claim 14 wherein said second data signal is carried by the same conduit that carries said second interrogation signal.

16. A method of processing seismic data signals as described by claim 13 wherein first and second remote acquisition terminals are separated by a predetermined distance and each receive seismic signals from a predetermined plurality of seismic transducer channels, said time interval being a function of a transmission bit rate respective to said first and second data signals.

17. A method of processing seismic data signals as described by claim 13 wherein said time interval is also a function of the number of seismic transducer channels connected to each remote acquisition terminal.

19. A method of processing seismic data signals as described by claim 18 wherein a third data acquisition terminal in said first receiver line transmits third data signals to an acquisition terminal in a second receiver line.

20. A method of processing seismic data signals as described by claim 169 wherein said third data signals are transmitted in response to a third interrogation signal from the acquisition terminal in said second receiver line.

12. An apparatus for recording seismic survey data comprising;

a. a plurality of geophones for receipt of seismic event reflections and for transmission of first signals responsive to such reflections;

b. a plurality of signal processing modules having interrogate signal processors;

c. plurality of signal transmission channels between said geophones and said signal processing modules; and

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d. digital communication conduit connecting a plurality of said signal processing modules along a signal receiver line to a data recording unit having an interrogate signal transmitter.

13. A method of processing seismic data signals transmitted by a plurality of remote acquisition terminals along a common receiver line whereby first data signal transmission from a first acquisition terminal is initiated upon receipt of a first interrogation signal, transmission of a second interrogation signal from said first acquisition terminal to a second acquisition terminal is initiated at a time interval following receipt of said first interrogation signal by said first acquisition terminal, second data signal transmission from said second acquisition terminal being initiated upon receipt of said second interrogation signal, said time interval being coordinated to minimize the time delay between said first and second data signals.

18. A method of processing seismic data signals transmitted by a plurality of remote acquisition terminals respective to a plurality of a common receiver lines, said receiver lines emanating from a common base line whereby first data signal transmission from a first acquisition terminal along a first receiver line is initiated upon receipt of a first interrogation signal, transmission of a second interrogation signal from said first acquisition terminal to a second acquisition terminal along said first receiver line is initiated at a time interval following receipt of said first interrogation signal by said first acquisition terminal, second data signal transmission from said second acquisition terminal being initiated upon receipt of said second interrogation signal, said time interval being coordinated to minimize the time delay between said first and second data signals.

21. A method of remotely configuring a network of seismic survey equipment comprising first plurality of seismic signal processing and communication modules connected along each of a plurality of receiver lines, said receiver lines respectively connected to a base line module, said base line module being connected along a base line, said base line respectively connected to a central recording unit, a second plurality of seismic modules in one receiver line connected to seismic signal processing and communication modules in another receiver line whereby data signal transmission routes from each of said seismic signal processing and communication modules to said central recording unit is directed by command signals from said central recording unit.

22. A method of remotely configuring a network of seismic survey equipment as described by claim 21 wherein signal transmission connections between seismic modules in the same receiver line are selectively made and broken by command signals issued from said central recording unit.

26. The method as described by claim 25 wherein the configuration of the network is accomplished by the operator using a controlling computer connected to the network with a true scale map projected on a computer monitor showing the physical features of the survey area and the seismic survey equipment items;

and also using computer interaction tools and appropriate system software that understands the survey equipment communication capabilities, status and requirements and that guides the operator in the process.

27. The method as described by claim 25 wherein the network configuration chosen by the operator also defines the sequential order in which data packets, containing seismic amplitudes originated by said seismic signal processing and communication modules, will arrive at each successive receiver line signal processing and communication module, at each base line signal processing and communication module and at the central recording unit, for each time sample.

28. A method as described by claim 25 wherein the transmission of data from said receiver line and base line signal processing and communication modules excludes any explicitly identifying information about data origin, instead relying on implicit information from the sequential order of said data packets to identify the originating signal processing and communication module and approximate time of origination.

30. A method as described by claim 29 wherein a first and a second receiver line are each connected to the base line via respective first and second base line modules and where respective ends of said first and second receiver lines are joined by connecting communication conduits such that two signal pathways are provided to said signal recording system that are selectable from said central recording system.

31. A method as described by claim 29 wherein said base line is constructed by combining multiple communication conduits of the same type and signal carrying capacity as the communication conduits in said receiver line.

32. A method as described by claim 30 wherein said multiple communication conduits of said base line may be physically separated to allow distribution of base line communication capacity in two portions along two pathways forking from the original base line pathway and a method of rejoining the two portions of base line communication capacity at a further point along the pathways where the branching pathways rejoin.

33. A method as described by claim 29 wherein the construction of said receiver line allows receiver line components to be substituted for base line components to form a functional base line for transmitting said digital signals.

34. A method as described by claim 29 wherein a multiplicity of substantially identical and essentially parallel communication conduits are contained in said receiver line.

35. A method as described by claim 33 in which the receiver and base line routing of signals to the central recording system are selectable by commands from the central recording system.

36. A method as described by claim 29 wherein a multiplicity of substantially identical and essentially parallel communication conduits are contained in said base line.

37. A method as described by claim 35 in which the receiver and baseline routing of signals to the central recording system are selectable from the central recording system.

23. A method of recording seismic survey data comprising the steps of:

a. Generating a terrestrially transmitted seismic survey event;

b. Detecting seismic reflections of said event by a plurality of physically spaced sensors;

c. Generating by said sensors, respective sensor signals corresponding to said seismic reflections;

d. Receiving said sensor signals by respective first and second signal processing modules connected by signal carrier cable;

e. Transmitting digital signals corresponding to said seismic reflections by said first and second signal processing modules along first and second signal channels to a signal recording system, said digital signal transmissions being at a signal power selected as a function of the spatial distance between said signal processing modules and also of the transmission characteristics of said signal carrier cable between the modules, said power selection having been determined to be adequate but not excessive to provide reliable communication of data.

24. A method of recording seismic survey data comprising the steps of:

a. Generating a terrestrially transmitted seismic survey event;

b. Detecting seismic reflections of said event by a plurality of physically spaced sensors;

c. Generating by said sensors, respective sensor signals corresponding to said seismic reflections;

d. Receiving said sensor signals by respective first and second signal processing modules;

e. Transmitting digital signals corresponding to said seismic reflections by said first and second signal processing modules to a signal recording system, said digital signals being transmitted in data packets, each packet comprising a finite number of digital data bits, said packets being transmitted in a sequential order that enables said signal recording system to determine the signal processing module origin of a specific data packet without explicit identification data among the digital data bits.

25. A method of remotely configuring a network of seismic survey equipment comprising seismic signal processing and communication modules, receiver line cables, base line signal processing and communication modules, and base line cables connecting to a central recording unit to optimize the transmission of commands to said modules and to also to optimize the transmission to the central recording unit of seismic signals using the given seismic survey equipment in the presence of natural and man-made obstacles and barriers to the placement of equipment and best overcoming the partial or total failure of some of said modules, receiver lines and base lines through the provision of multiple signal conduits that are selectable.

29. A method of recording seismic survey data comprising the steps of:

a. generating a terrestrially transmitted seismic survey event;

b. detecting seismic reflections of said event by a plurality of physically spaced sensors;

c. generating by said sensors, respective sensor signals corresponding to said seismic reflections;

d. transmitting said sensor signals along a plurality of first and second signal channels to respective first and second signal processing modules;

e. transmitting digital signals corresponding to said sensor signals by said first and second signal processing modules along a receiver line comprising a first plurality of communication conduits, said receiver line being connected to a signal processing and communication base line module positioned along a base line, said base line comprising a second plurality of communication conduits, said digital signals being further transmitted along said base line to a signal recording system; and

,

f. connecting said first plurality of communication conduits to said first and second signal processing modules with connectors that are identical in physical form and connectability to connectors joining said second plurality of communication conduits to said base line module and to said signal recording system.

38. A method as described by claim C26 wherein said first and second signal processing modules are responsive to signal commands from said central recording system to change from performance of receiver line functions to performance of base line module functions.

39. A method of recording seismic survey data comprising the steps of:

a. Generating a terrestrially transmitted seismic survey event;

b. Detecting seismic reflections of said event by a plurality of physically spaced sensors;

c. Generating by said sensors, respective sensor signals corresponding to said seismic reflections;

d. Transmitting said sensor signals along a plurality of first and second signal channels to respective first and second signal processing modules;

e. Transmitting digital signals corresponding to said seismic reflections by said first and second signal processing modules to a signal recording system, said digital signals being transmitted via a plurality of communication conduits in a Receiver Line and said Receiver Line being connected to a signal processing and communication module positioned along a Base Line, and said digital signals being further transmitted along said Base Line containing a second plurality of communication conduits and being further connected to the signal recording system;

f. Commencing the digital sampling to form said digital signals in said first and second signal processing modules upon receipt of a digital command signal from a control system;

g. Controlling the sequential timing of the subsequent digital samples comprising said digital signals using independent clock devices in each of said first and second signal processing modules;

h. Periodically recording times from said independent clock devices; and

,

i. Using said periodically recorded times and a master clock to resample said digital signals at correct times according to said master clock to achieve synchronous sampling of said digital signals and correct for drift of said independent clocks.

40. A method of recording seismic survey data comprising the steps of:

a. Generating a terrestrially transmitted seismic survey event;

b Detecting seismic reflections of said event by a plurality of physically spaced sensors;

c. Generating by said sensors, respective sensor signals corresponding to said seismic reflections;

d. Transmitting said sensor signals along a plurality of first and second signal channels to respective first and second signal processing modules;

e. Transmitting digital signals corresponding to said seismic reflections by said first and second signal processing modules to a signal recording system, said digital signals being transmitted via a plurality of communication conduits in a Receiver Line and said Receiver Line being connected to a signal processing and communication module positioned along a Base Line, and said digital signals being further transmitted along said Base Line containing a second plurality of communication conduits and being further connected to the signal recording system;

f. Commencing the digital sampling to form said digital signals in said first and second signal processing modules upon receipt of a digital command signal from a control system;

g. Controlling the sequential timing of the subsequent digital samples comprising said digital signals using independent clock devices in each of said first and second signal processing modules;

h. Determining the total delays between the issuance of said digital command signal by said control system and the execution of said digital sampling by each of said first and second signal processing modules through summing previously measured network element delays and predictable deliberately-imposed delays in other elements of the networks connecting said control system and said first and second signal processing modules; and

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i. Using said total delays and a desired schedule of sampling times according to a master clock to resample said digital signals at correct times according to said schedule and to said master clock, to achieve synchronous sampling of said digital signals.