Seismic data acquisition system using acquisition stations positioned on the sea ground

摘要

Relay buoys and seabed seismic collection stations each have an acoustic transmitter made using an acoustic transponder, an acoustic positioning module, and an acoustic communication module to exchange positioning or control data from the central station, or seismic data collected by the collection device to be transmitted to the central station between the buoys and seabed stations A system for collecting seismic data on an immersed subterranean formation comprises a central control and collection station (CCRU) and several relay buoys (RCB) which float on the surface of the water. Each buoy has a control module (CPU), a receiver (Rx) of positioning signals of GPS satellite type, and a VHF radio transmitter for exchanging data with the central control station. A number of seabed seismic collection stations (DSAU) each have a sealed body containing a pressure detector (PS) and connected to a profiled part or arrow forming a seat for seismic receptors (SRU). These descend by gravity to the bottom of the water. Each seabed collection station includes a control assembly (UC) and a data collection device (DAM) collecting the seismic data from the receptors and the pressure detector. The seismic acquisition stations are divided into several groups and each relay buoy is designed to exchange position and control data with the group nearest to the buoy. Each acquisition station includes means of storing seismic recording traces for the seismic signals detected at the station and means in the control unit for ordering the transfer to a relay buoy of at least part of the stored seismic traces at a particular transmission frequency. Each station has means of optical transmission to send the recorded seismic data to a relay buoy or a vehicle. Each buoy includes means of recording seismic data from the acquisition stations and transmitting it to the central control station. Each acquisition station has means of floating and detaching itself from its anchor on a command from the central station, and can be attached to an industrial transmission network to transfer data direct to the central station. An Independent claim is also included for seismic surveying where an array of undersea acquisition stations are planted on the seabed under gravity, their locations determined, seismic operations are carried out so the acquisition stations can collect the necessary data, and the positioning and seismic data are recovered by a central control station, via relay buoys.