Institut Francais Du Pe'trole

Gerard Thierry

Joseph Rialan

Christian Grouffal

Bernard Deconinck

Renate Bary

Andre Oliveres

The invention pertains to transmission to a remote station, by means of transmission channels (generally radio transmission channels), of seismic data acquired by a data collection equipment comprising a plurality of acquisition units, each being suited to acquire, to store and preferably to compress the data to be transmitted. The invention comprises ordered storage, in a high-capacity memory (flash type memory for example) of each acquisition unit (Ai), of data obtained during successive emission-reception cycles (acquired and possibly preprocessed seismic data) so as to form a stream of stored data to be transmitted, and progressive transfer of the stored data stream from each acquisition unit to the remote station by means of the transmission channel, by reading each storage memory, with a time lag in relation to the time of their storage depending on the transmission rate of each transmission channel and on the transmission mode selected with preferably, if sending of the data of a cycle is delayed, sending of at least partial data, compressed or not, for quality control purposes. The data transmitted are reconstituted at the remote station. The method can be used for large-scale seismic data transmission.

Method and system for transmitting seismic data to a remote collection

Method and device for simplifying the localization of a subsurface zone

A digitalization assembly of the over-sampling type includes an analog to digital converter (2) producing at a frequency F=kf small-format p samples and a digital filter (3) which, through the summation of a certain number n of over-samples, produces validated larger P-format samples at the frequency f, at instants fixed by a clock. In order to readjust the sampling instants in relation to an outside event which can occur at any time, a temporary memory store (5) is inserted between the converter (2) and the filter (3) and, according to the instant of arrival of this event, the appropriate samples to be sent towards the filter for their summation are selected.

Method and device for synchronizing on an outside event the sampling of

In a data acquisition for seismic exploration, where the terrain is rugged or includes natural features which prohibit satisfactory radio communication between a central control and recording system and a plurality of seismic data signal acquisition devices, a relay element and a transmission cable are provided so that those acquisition devices which are not capable of satisfactory radio communication with the central control and recording system communicate instead with the relay element either by transmission cable or radio transmission and the relay element in turn communicates with the central control and recording system either by radio transmission or transmission cable, respectively.

Device for transmitting signals by radio and cable between a central

A method and device are provided for initializing acquisition apparatus including the use of coded infrared rays for transmitting data and a control case, the initialization being provided by modulating a light beam in amplitude by means of a carrier signal, this latter being modulated both in frequency and in phase and the modulation depending on the initialization signals. A programmable processing unit delivers the digital data to an infrared ray transmitter, the light signals received in return from the acquisition cases provided with similar transmission means being received by an infrared receiver, decoded and reshaped before being applied to the processing unit.

Method and device for initializing data, and particularly seismic data,

A system is provided for radio transmission between a central control and recording laboratory and spaced apart acquisition boxes in which relay transmission units are used for communicating with boxes which are directly inaccessible. It includes a centralization unit adapted for managing the exchanges of orders or data from the central laboratory with directly accessible boxes by means of a radio link in a first frequency band (f2), on the one hand and with the relay units by means of a radio link in another frequency band (f1). These latter manage the radio links with the inaccessible boxes by means of radio links at a frequency (f3) distinct from (f2). The relay units and the centralization unit are programmed for automatically managing the links between the central laboratory and any one of the boxes, whether they are direct or indirect, and, on the other hand, for reserving a part of the interrogation time of each box for the transmission of service data indicative of their correct operation.

Seismic signal transmission system using relay radios

In a system for seismic exploration, a narrow passband channel of relatively-slow transmission speed is used to transmit commands from a control station to one or more remote signal acquisition devices to initiate acquisition and processing of echo signals generated by triggering of a seismic signal generator at a selected reference time. To permit use of the slow speed transmission channel for transmitting commands without delay in the recording of the echo signals, a first command to initiate processing and recording of received signals is transmitted to the acquisition devices prior to the selected reference time by an amount of time at least equal to the transmission time of the narrow passband channel. This first command also initiates in each acquisition device the counting of signal samples which are being recorded at a predetermined rate. A second command is transmitted at the selected reference time and upon receipt of this command, the count of signal samples is latched and a number is subtracted from this count based on the transmission time of the narrow passband channel to identify the signal samples which were processed and recorded beginning at the selected reference time.

Method for the remote control of signal acquisition devices by means of

Device for the sequential transmission of signals by radio or by cable between a central control and recording station and local data acquisition apparatuses, comprising cables connecting said data acquisition apparatuses to the central station and radio transmission and reception means associated with each acquisition apparatus and with the central station, and switching means for establishing the cable connection and interrupting the radio connection between the central station and any particular apparatus for which said radio connection becomes defective as a result of obstacles on the path between the location of said apparatus and that of the central station.

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Nanterre, France

Gerard Thierry