Seabed seismic data acquisition system and acquisition method based on distributed optical fiber sensing

Abstract

The invention provides a seabed seismic data acquisition system and acquisition method based on distributed optical fiber sensing. An air gun source excitation ship is provided with a plurality of pull-type air gun sources; a plurality of boxes are distributed on the data acquisition armored optical cable at equal intervals, a surrounding optical fiber ring is arranged in each box, and an optical fiber attitude sensor is arranged at the top of each box; and the distributed optical fiber acoustic wave sensing modulation-demodulation instrument is arranged in a buoy on the sea surface, is connected to one end or two ends of the data acquisition armored optical cable, and is used for receiving optical fiber earthquake signals distributed along the data acquisition armored optical cable and signals of the optical fiber attitude sensors. The production and manufacturing cost of the seabed seismic data acquisition system is greatly reduced, the seabed seismic data acquisition system is convenient to use and maintain in offshore production, the seabed seismic data acquisition system can be made longer than a conventional active seabed seismic data acquisition cable, more seismic sensors can be arranged on each cable, and high-density seabed seismic data can be acquired more efficiently.

Description

technical field [0001] The invention belongs to applied geophysical prospecting methods, relates to marine seismic prospecting technology, in particular to a seabed seismic data acquisition system and acquisition method based on distributed optical fiber sensing. Background technique [0002] There are two main methods of seabed seismic data acquisition at present, one is single-component, two-component, three-component or four-component submarine seismic data acquisition cable (OBC) sinking into the seabed to collect seismic data, and the other is independent three-component or four-component The component bottom seismic data acquisition stations (OBS and OBN) sink to the bottom to acquire seismic data, both of which are excited while being towed in the water using independent marine seismic airgun excitation sources. The submarine seismic data acquisition cable sunk into the seabed, its working method is that the submarine seismic cable (OBC) is first dropped and laid to t...

AI Technical Summary

Problems solved by technology

This type of sinking acquisition station is large in size, high in cost, and heavy in weight, so it is impossible to deploy a large number of high-density two-dimensional submarine seismic data acquisition survey lines or three-dimensional survey networks on the seabed

In addition, when the acquisition station is released, it sinks freely without fixed-point release accuracy control. When it is recovered, the submarine seismic acquisition station is brought to the sea surface by glass floats. The construction efficiency is low, and the submarine seismic acquisition is caused by the failure of the acoustic or mechanical release device. The station cannot be separated from the counterweight cement block, resulting in the recovery failure of the submarine seismic acquisition station and loss

[0004] The existing conventional submarine seismic data acquisition cable (OBC) has a plurality of four-component submarine seismic signal acquisition units distributed along the cable at equal intervals, which makes the weight of the conventional submarine seismic data acquisition cable extremely large, and can only be used for operations where the water depth does not exceed 500 meters of sea area

In addition, due to the limited data transmission capacity of the submarine cable, it is impossible to transmit all the submarine seismic data collected on the ultra-long acquisition cable to the buoy on the sea surface in real time or to the seismic data acquisition computer on the air gun source excitation ship.

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