Seismic transmission method and system utilizing concentration units

• US 5,706,250 A
• Filed: 10/30/1996
• Issued: 01/06/1998
• Est. Priority Date: 10/12/1992
• Status: Expired due to Term

• Current Assignee: Institut Francais Du Petrole
• Original Assignee: Institut Francais Du Petrole
• Inventors: Rialan, Joseph, Grouffal, Christian
• Primary Examiner(s): Moskowitz, Nelson
• Application Number:
  US08/741,102
• Time in Patent Office: 433 Days
• Field of Search: 367/77, 367/80, 340/825.15
• US Class Current: 367/77
• CPC Class Codes: G01V 1/22 Transmitting seismic signals to recording or processing apparatus

Abstract

Seismic data acquisition devices (BA) distributed in an exploration zone are divided into n groups (GA1 to GAn) and, therein, into sub-groups having each a specific frequency for communicating with a concentration unit (Ck) which is connected to a central station (1) through Hertzian channels or cables or optical fibers. Acquisition devices in the various subgroups communicate simultaneously with the corresponding concentration unit (Ck) during predetermined emission windows. The concentration unit collects the signals received from the acquisition devices to transmit them in series to station (1). The acquisition devices are adapted for delaying their own emission window according to the rank which has been previously assigned thereto within the respective subgroups thereof.

Claims

1. A method of transmitting digitized data stored in a plurality of seismic data acquisition devices distributed in an acquisition zone produced from seismic signals transmitted through a subsoil of a geological formation containing discontinuities from a number of concentration units to a control and recording station comprising:

dividing at least part of the acquisition devices into groups with a number of the groups being at least equal in number to the number of concentration units with each group including a number of acquisition devices;

assigning to each group a number of radio transmission frequencies with the assigned number of radio transmission frequencies being less than the number of acquisition devices and defined for each group, the acquisition devices of each group being associated with a different one of the concentration units and having a transmitting device operating on at least one of the assigned number of transmission frequencies;

subdividing each group into at most the assigned number of subgroups of acquisition devices utilizing identical transmission frequencies and assigning different serial numbers to the acquisition devices of each subgroup;

sending a transmission order from the control and recording station to all of the concentration units and the acquisition devices to request transmission of signals; and

transmitting signals successively from all of the acquisition devices of one of the subgroups with each signal being within an emission window staggered from other emission windows used to transmit other of the successive signals with each emission window being dependent upon the assigned serial number in the subgroup with the transmission of all of the subgroups being made during a subgroup transmission time interval.

2. A method in accordance with claim 1 wherein:

the transmitting device transmits on a plurality of different frequencies with an order being sent from the control and recording station to all of the acquisition devices of each group specifying a transmission frequency assigned to one of the subgroups.

3. A method in accordance with claim 1 further comprising:

sending an order from the control and recording station to all of the acquisition devices of each group assigning different serial numbers to all of the acquisition devices of each of the subgroups.

4. A method in accordance with claim 1 wherein:

at least part of the concentration units are provided with a radio communication device to communicate with the control and recording station using a radio frequency which is distinct for each of the concentration units with signals being transmitted to the acquisition devices of the subgroups being transmitted successively on the distinct radio frequency.

5. A method in accordance with claim 1 wherein;

at least a part of the concentration units are connected to the control and recording station by non-wireless transmission channel.

6. A transmission system for transmitting digitized data stored in a plurality of seismic data acquisition devices distributed in an acquisition zone produced from seismic signals transmitted through a subsoil of a geological formation containing discontinuities from concentration units to a control and recording station comprising:

a number of concentration units with each concentration unit having a transmitting device for communication with the control and recording station and a radio transmitting and receiving set for communicating simultaneously on several frequencies with a group of the acquisition devices; and

each acquisition device of the group having a storage of a serial number determining a priority rank of the acquisition device in a subgroup of the acquisition devices, a transmitting and receiving device which transmits on at least one radio transmission frequency, a decoder for decoding orders transmitted to the acquisition device from the control and recording station, a timing device for generating a time reference common to all of the acquisition devices of the group, and a processing device for determining an emission window for transmitting signals successively from all of the acquisition devices in the subgroup with the emission window of each of the acquisition devices being staggered from the emission window of the other acquisition devices in dependence upon the stored serial number.

7. A transmission system in accordance with claim 6 wherein:

at least part of the acquisition devices have a transmitting device for transmitting data on a non-wireless channel.

8. A transmission system in accordance with claim 6 wherein:

at least part of the concentration units have a transmitting device for transmitting data on a non wireless channel.

9. A transmission system in accordance with claim 6 wherein:

at least part of the acquisition devices include a transmitter and receiver which operates on a plurality of selectible transmission frequencies assigned to the subgroup and a switch controlled by a processing unit for selecting one of the selectible transmission frequencies.

10. A system in accordance with claim 9 wherein:

the processing unit includes and arithmetic unit, a storage unit and an interface element permitting assigning of a serial number to an associated acquisition device.

11. A system in accordance with claim 9 wherein:

the transmitter and receiver of each of the at least part of the acquisition devices includes an oscillator controlled by a circuit having a frequency synthesizer applying a reduction factor dependent upon an output of the switch to the frequency synthesizer for controlling a reference frequency thereof, and a receiver, coupled the processing unit, for receiving transmissions for controlling the switch.

12. A system in accordance with claim 11 wherein:

the oscillator includes a modulation input for receiving signals of an array of the a acquisition devices; and

a coding element, coupled to the modulation input, for coding the signals received from the array of the acquisition devices, and an amplifier, having an output coupled to an output of the coding element and an output coupled to the modulation input, for amplifying coded signals produced by the coding element.

13. A system in accordance with claim 6 wherein:

each concentration unit includes a receiver for separating signals received simultaneously on a plurality of radio channels into a plurality of different outputs with each output containing a signal transmitted on a different one of the radio channels, a plurality of storages with a different storage being coupled to a different output for storing the outputted signal, a control, coupled to the plurality of storages, for controlling sequential readout of the stored outputted signal, and a transmitting device for transmitting the sequentially readout signals to the control and recording station.

14. A system in accordance with claim 7 wherein:

each concentration unit includes a receiver for separating signals received simultaneously on a plurality of radio channels into a plurality of different outputs with each output containing a signal transmitted on a different one of the radio channels, a plurality of storages with a different storage being coupled to a different output for storing the outputted signal, a control, coupled to the plurality of storages, for controlling sequential readout of the stored outputted signal, and a transmitting device for transmitting the sequentially readout signals to the control and recording station.

15. A system in accordance with claim 8 wherein:

each concentration unit includes a receiver for separating signals received simultaneously on a plurality of radio channels into a plurality of different outputs with each output containing a signal transmitted on a different one of the radio channels, a plurality of storages with a different storage being coupled to a different output for storing the outputted signal, a control, coupled to the plurality of storages, for controlling sequential readout of the stored outputted signal, and a transmitting device for transmitting the sequentially readout signals to the control and recording station.

16. A system in accordance with claim 9 wherein:

each concentration unit includes a receiver for separating signals received simultaneously on a plurality of radio channels into a plurality of different outputs with each output containing a signal transmitted on a different one of the radio channels, a plurality of storages with a different storage being coupled to a different output for storing the outputted signal, a control, coupled to the plurality of storages, for controlling sequential readout of the stored outputted signal, and a transmitting device for transmitting the sequentially readout signals to the control and recording station.

17. A system in accordance with claim 10 wherein:

each concentration unit includes a receiver for separating signals received simultaneously on a plurality of radio channels into a plurality of different outputs with each output containing a signal transmitted on a different one of the radio channels, a plurality of storages with a different storage being coupled to a different output for storing the outputted signal, a control, coupled to the plurality of storages, for controlling sequential readout of the stored outputted signal, and a transmitting device for transmitting the sequentially readout signals to the control and recording station.

18. A system in accordance with claim 11 wherein:

each concentration unit includes a receiver for separating signals received simultaneously on a plurality of radio channels into a plurality of different outputs with each output containing a signal transmitted on a different one of the radio channels, a plurality of storages with a different storage being coupled to a different output for storing the outputted signal, a control, coupled to the plurality of storages, for controlling sequential readout of the stored outputted signal, and a transmitting device for transmitting the sequentially readout signals to the control and recording station.

19. A system in accordance with claim 12 wherein:

each concentration unit includes a receiver for separating signals received simultaneously on a plurality of radio channels into a plurality of different outputs with each output containing a signal transmitted on a different one of the radio channels, a plurality of storages with a different storage being coupled to a different output for storing the outputted signal, a control, coupled to the plurality of storages, for controlling sequential readout of the stored outputted signal, and a transmitting device for transmitting the sequentially readout signals to the control and recording station.