Institut Francais Du Pe'trole

Michel Guion

R&eacute;nate Bary

G&eacute;rard Thierry

A method and system for transferring synchronization data between a central control and seismic recording station and dependent stations in all the cases where the time of transmission through the connection channels between the elements may be liable to too great fluctuations is disclosed. The invention provides a central station (CCU) and intermediate local control and concentration stations (RRS), each connected to local acquisition units (RTU), with a common time reference or clock (H) (that can for example be provided by a satellite positioning network of a well-known type such as the GPS system, or based on the carrier frequency of a radio transmitter) which is picked up by specialized receivers associated with the elements of the seismic device, and in using this common reference to calculate the real transmission time and to local readjust seismic acquisition units (RTU).

Method and system for synchronizing elements of a seismic device using a standard transmission network and an external time reference

Transmission method for connecting together a central control and seismic recording station (SCC), local intermediate control and concentration stations (RRS) and local seismic data acquisition, processing and transmission units (RTU). It comprises using a transmission network (L, RFi) working according to a particular transmission protocol in order to interconnect the central station and the intermediate stations for example, previous measurement of the data transit time on the transmission channels between the central station and acquisition units (RTU), pretriggering of seismic data acquisition by acquisition units (RTU), the holding time interval in relation to the time of reception of reference signal (TB) being fixed and greater than the transit time, and applying to reference signal (TB), in the intermediate station, an adjusted compensation delay to take account of the effective transfer time fluctuations linked with its passage through multitask control means of the intermediate stations and transmission network (L, RFi) in order to respect the holding time interval. All the acquisition units can thus be perfectly synchronized. The system can be applied for transmission of a TB concomitant with the triggering of a seismic source for example.

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rue de la République, France

Michel Guion