System for gathering and recording seismic signals

• US 3,886,494 A
• Filed: 11/13/1972
• Issued: 05/27/1975
• Est. Priority Date: 11/13/1972
• Status: Expired due to Term

• Current Assignee: Haines C. Hibbard, Richard J. Kostelnicek
• Original Assignee: Haines C. Hibbard, Richard J. Kostelnicek
• Inventors: Kostelnicek, Richard J., Hibbard, Haines C.
• Primary Examiner(s): Wilbur, Maynard R.
• Assistant Examiner(s): Birmiel, H. A.
• Application Number:
  US05/306,096
• Time in Patent Office: 925 Days
• Field of Search: 340/15.5TS,15.5FC,15.5MC 325/1,3,13,113 179/15BD 343/6.8LC
• US Class Current: 367/77
• CPC Class Codes: G01V 1/223 Radioseismic systems

Abstract

A wireless seismic data acquisition system wherein seismic data detected at a plurality of remote detecting locations is to be transmitted to a remote recording location is disclosed. At a given detecting location, seismic data samples are digitally encoded for radio data transmission to the recording location via a radio frequency relay system comprising data acquisition and relay units located at the various detecting locations. The data samples from the various units located at the detecting locations are injected into the stream of data being relayed by radio to the recording location according to a predetermined program. Units at each detecting location function to relay radio data transmissions from one adjacent location to another, and at the proper time initiate radio data transmissions for relaying thereof. The group of units initiating radio data transmissions is selectable from a larger number of such units by means of a radio signal from a remote control station. Units not within the selected group perform only the relay function.

Claims

1. In a seismic surveying process whereIn a seismic energy disturbance is produced at transmitting location for producing seismic impulses at detecting locations along a traverse, the improvement comprising:

transmitting control signals to each of a plurality of detecting locations located along said traverse, producing electrical signals at each of said detecting locations as a function of said seismic impulses, sampling said electrical signals at each of said detecting locations and generating distinctively coded signals representative of the magnitude of each sample; and

in response to said control signals, originating discrete transmissions of said coded signals in a predetermined sequence from a selected number of said detecting locations;

for each discrete transmissions, receiving and retransmitting said coded signals at each location in order along said traverse;

wherein the step of transmitting control signals includes the transmission of command signals which include selection signals for selecting the selected number of locations and timing signals for sequencing said selected number of locations, and wherein the step of generating distinctively coded signals includes the step of converting said electrical signals into binary coded signals, and further including the step of converting said binary coded signals into quaternary coded signals and an extra signal for differentiating between successive-like quaternary or extra signals.

2. The method of claim 1 wherein said step of converting to said quaternary signals and said extra signals includes producing corresponding signals at five separate frequency bands in the range of 500- 1000 MHz.

3. In a seismic surveying method wherein a seismic energy disturbance produces seismic impulses at a plurality of detecting locations along a traverse and electrical signals are generated at each of said detecting locations as a function of said seismic impulses, the improvement comprising:

a. sampling said electrical signals at each of said detecting locations and generating distinctively coded signals for radio transmission, said coded signals being representative of said sampled electrical signals, b. originating discrete radio transmissions of said coded signals in a sequence from a selected number of said plurality of detecting locations, and for each discrete transmission, receiving and retransmitting said transmission at each successive location in said selected number of locations, c. upon completing said sequence once, repeating steps (a) and (b) so that during each sequence, a different sample is transmitted;

d. placing said coded signals in binary word form, and e. converting said binary coded signals into quaternary coded signals and an extra signal for differentiating between successive like quaternary coded signals.

4. A method of transmitting seismic data via a radio frequency transmission link from one location to another location along a traverse comprising the following steps:

at a detecting location, sampling seismic data and producing coded signals from the sample, said coded signals being representative of a number of digit values; and

from said detecting location transmitting on different radio frequencies coded signals indicative of digits of different values, and when two coded signals are indicative of two successive digits of the same value, transmitting the coded signal indicative of the second digit on a different frequency from that on which the coded signal indicative of the first digit was transmitted.

5. The method of claim 4 further including in the step of producing coded signals, the step of producing a binary digital signal and the step of combining binary digits into said coded signal.

6. For use in a seismic surveying system for deriving indications of seismic energy, and for selectively relaying radio transmissions or originating a radio transmission, apparatus comprising:

radio receiver means for receiving coded radio frEquency data signals with no two successive data signals having the same frequency, and for respectively converting each of said data signals into corresponding and discrete time signals;

radio transmitter means for responding to said discrete time signals for transmitting coded radio frequency data signals, no two successive data signals having the same frequency;

sampling means for sampling electrical signals representative of seismic energy and for producing successive discrete time signals coded with respect to each sampled signal; and

selection means for selectively coupling the time signals from either said sampling means or said receiver means to said transmitter means.

7. The apparatus of claim 6 further including in said receiver means, separate electrical channels where each of said channels has a filter means for passing a preselected frequency, said electrical channels corresponding to the number of frequencies in said coded transmission signal, and means in said channels for converting the signals in said channels to discrete time signals.

8. The apparatus of claim 7 further including time spacer means for receiving the outputs of said channels, said time spacer means including pulse forming means for each channel, clocking means, and means in one of said channels for delaying the input signal by one time increment and for conjunctively with said clocking means operating said pulse forming means at pre-established time increment intervals.

9. The apparatus of claim 6 wherein said transmitter means includes:

a converter for converting said time signals into voltage signals, and means responsive to said voltage signals for producing corresponding radio frequency signals.

10. The apparatus of claim 6 and further including a frequency reference loop including:

first means for receiving said ratio frequency signals and for compensating said radio frequency signals for providing first radio frequency signals at a common frequency base, a source of radio frequency signals for providing second ratio frequency signals at said common frequency base, and second means for comparing said first and second ratio frequency signals and providing an error output control signal, said error output control signal being supplied to said first means.

11. A seismic surveying system for deriving indications of seismic impulses occurring at locations along a traverse, first means for generating control signals at a control station;

second means for transmitting said control signals from said control station;

third means for receiving said control signals at each of a plurality of locations located along said traverse;

fourth means for generating electrical signals at each of said plurality of locations as a function of said seismic impulses;

fifth means for sampling said electrical signals at each of said plurality of locations and generating distinctively coded signals representative of the values of said sampled electrical signals, including means for converting said electrical signals into binary coded signals and means for converting said binary coded signals into a quaternary coded signal and an extra signal for differentiating between successive like quaternary signals;

sixth means at each of said locations responsive to the received control signals for originating synchronized discrete transmissions of said coded signals in sequence at a predetermined sequence of locations;

seventh means at each of said locations for receiving and retransmitting each discrete transmission of said coded signals to relay said coded signals along said traverse to a recording location located on or near said traverse; and

the first means for generating control signals includes eighth means for generating command signals for selecting said selected number of locations and for generating timing signals to actuate said sixth means for synchronizing and sequencing said selected number of locations.

12. ApparaTus for use in a seismic surveying system for producing indications of seismic signals derived at locations along a traverse, comprising:

radio frequency receiver means for receiving a sequence of coded data signals from a location spaced therefrom on said traverse;

radio frequency transmitter means;

control means for producing control signals responsive to radio frequency signals from another location;

means for producing a sequence of coded digital data signals representative of samples of electrical signals indicative of detected seismic signals, selection means responsive to control signals from said control means for selectively coupling said receiver means or said means for producing a sequence of coded data signals to said transmitter means;

circuit means for producing a sequence of sets of binary digital signals representative of seismic signals;

binary register means for temporarily storing the binary digital signals from said circuit means; and

encoder means for encoding each set of binary digital signals from said binary register means.

13. The apparatus of claim 12 wherein the encoder means produces a set of distinctive signals each indicative of a pair of binary digital signals in a set.

14. The apparatus of claim 13 wherein the ratio frequency transmitter means produces output signals of a plurality of different frequencies, each frequency corresponding to similar distinctive signals in the sets of distinctive signals produced by said encoder means.

15. The apparatus of claim 12 wherein the encoder means includes first means for converting the digital signals into quaternary coded signals, and second means for producing an extra signal and inhibiting production of a quaternary coded signal whenever two successive quaternary coded signals of the same value would be produced, and further wherein the transmitter means includes means for changing the frequency of signals produced by said transmitter means to values related to the output signals of said encoder means.

16. For use in a seismic surveying system for deriving indications of seismic energy, apparatus comprising:

radio frequency receiver means for receiving coded signals which include seismic data signals successively occurring at regular time intervals with no two successive data signals having the same frequency;

first means for separating the frequency components of said coded signals and applying the resulting signals on separate signal channels;

second means for converting the signals in said channels into discrete time signals and for delaying said discrete time signals by a predetermined time interval; and

third means including radio frequency transmitter means connected to said second means for producing radio frequency signals of different frequencies dependent on the channel from which a delayed time signal is received thereby such that the signal is of the same frequency as the radio frequency signal applied to the channel.

17. The apparatus of claim 16 wherein said second means includes pulse forming means for each channel, clocking means, and means for delaying the signal applied to each channel by one time increment of said clocking means and for conjunctively with said clocking means operating said pulse forming means at pre-established time increment values.

18. The apparatus of claim 16 wherein the third means includes a converter for converting said time signals into voltage signals, and means responsive to said voltage signals for varying the frequency of said radio frequency transmitter means.

19. Apparatus for producing radio frequency signals indicative of seismic signals comprising:

radio frequency transmitter means;

first means for producing binary digital signals indicative of said seismic signals, including a register for reciving said binary digital data signals in parallel and means for producing two serial binary digital data streams of information for encoding;

second means for encOding said binary ditial signals according to a multidigit code wherein each digit of the code represents a distinctive pair of binary digits from said first means; and

third means for varying the frequency of said transmitter means between a plurality of frequencies in accordance with the encoded output signals of said second means..

20. The apparatus of claim 19 wherein said first means further includes:

binary gain amplifier means the gain of which is varied in accordance with a schedule of powers of two and which includes means for producing first binary digital signals indicative of said gain at any time;

means for producing second binary digital signals indicative of the amplified signals of said amplifier at time spaced intervals; and

means for concomitantly loading said first and second binary digital signals into said register.

21. In a method of seismic prospecting wherein a seismic disturbance is generated at a generating location and the resulting seismic energy is detected at a pluarlity of seismic detecting locations spaced along a traverse of the earth the improvement which comprises:

generating at each detecting location digitally encoded signals which are representative of the seismic energy detected at such detecting location, radio transmitting the digitally encoded signals from each of said detecting locations in sequence along said traverse toward one end thereof, separating the radio transmissions from successive detecting locations by time intervals, during any given time interval radio relaying toward one end of said traverse the radio signals transmitted immediately prior to each such time interval from their respective detecting location to successive ones of said detecting locations located between said respective detecting location and said one end of said traverse;

the radio transmissions being made on n + 1 different frequencies where n is the number of different digits in the digital code, the transmission of each digit value in said code being transmitted on a particular one of said n frequencies except when the same digit value occurs twice in succession whereupon the second occurrence of said digital value is transmitted on the n + 1 frequency.

22. A method as defined in claim 21 in which the digital code is binary and the radio transmissions are on three frequencies.

23. A method as defined in claim 21 in which the digital code is quaternary and the radio transmissions are on five frequencies.

24. Apparatus for detecting seismic energy in the earth which comprises:

transducer means to generate an electrical signal which is representative of said seismic energy;

means to sample said electrical signal;

means to encode said sample signal in a digital code having n digit values where n is a whole even number greater than one;

radio transmission means to transmit said digitally encoded sample signal as a radio transmission wherein each digit having a given one of said digit values is transmitted for an interval of time on a selected one of n different frequencies, except where said transmission has been immediately preceded by a transmission on the same said selected frequency whereupon said transmission means transmits said digit on an additional frequency distinct from said n frequencies;

radio receiver means adapted to receive radio tranmissions of the type transmitted by said transmission means; and

control means adapted to actuate said transmission means in response to either the transmissions received by said radio receiver means or the sample signals produced by said digital encoding means.

25. Apparatus as defined in claim 24 including second radio receiver means adapted to receive radio transmissions for actuating said control means.

26. Apparatus as defined in claim 24 wherein a single additional frequency serves as the additional frequency for each of said digital values.

27. Apparatus as defined in claim 24 wherein n has a value of 2, and the digitally encoded sample signal transmitted by said transmission means is encoded in a binary code.

28. Apparatus as defined in claim 24 wherein n has a value of 4, and the digitally encoded sample signal transmitted by said transmission means is encoded in a quaternary or four level digital code.

29. Apparatus as defined in claim 24 wherein n has a value of 8, and the digitally encoded sample signal transmitted by said transmission means is encoded in an octal code.

30. Apparatus for detecting seismic energy in the earth which comprises:

transducer means to generate an electrical signal which is representative of said seismic energy;

means to sample said electrical signal;

means to encode said sample signal in a digital code having n digit values where n is a whole even number greater than one;

signal transmission means to transmit said digitally encoded sample signal as a transmission wherein each digit having a given one of said digit values is transmitted for an interval of time on a selected one of n different frequencies, except where said transmission has been immediately preceded by a transmission on the same said selected frequency whereupon said transmission means transmits said digit on an additional frequency distinct from said n frequencies;

receiver means adapted to receive transmissions of the type transmitted by said transmission means; and

control means adapted to actuate said transmission means in response to either the transmissions received by said receiver means of the sample signals produced by said digital encoding means.