A small intelligent marine seismic electromagnetic data acquisition system

Abstract

The invention discloses a small-scale intelligent marine seismic electromagnetic data acquisition system, which includes an intelligent acquisition station placed underwater and two pairs of electric field detection devices installed outside the intelligent acquisition station; an ultra-short baseline transponder, a computer Control system, four-component seismic data sensor unit, magnetic field sensor and three-component attitude sensor; the output end of the four-component seismic data sensor unit is connected with the four-component seismic data acquisition unit, and the output end of the magnetic field sensor is connected with the magnetic field data acquisition unit; the electric field data The acquisition device, the magnetic field data acquisition unit, the three-component attitude sensor, the ultra-short baseline transponder and the four-component seismic data acquisition unit are respectively connected with the computer control system. The present invention can simultaneously collect marine seismic data, marine magnetotelluric data and marine controllable source electromagnetic data, can increase the data collection amount of one-time construction by several times, and effectively improve the target detection accuracy.

Description

technical field [0001] The invention belongs to applied geophysical prospecting methods, and relates to marine seismic prospecting, marine natural electromagnetic field source and controllable source electromagnetic prospecting technology, in particular to a small-scale intelligent marine seismic electromagnetic data acquisition system. Background technique [0002] At present, there are three main methods of marine electromagnetic data collection: [0003] One is that the independent collection station sinks to the bottom and the excitation source is towed, such as EMGS, OHM, Schlumberger and other international commonly used submarine electromagnetic collection stations and high-power towed field sources. Dragging excitation above the station can simultaneously complete marine controlled source electromagnetic and magnetotelluric data acquisition. [0004] The second is the synchronous towing of the acquisition cable and the excitation cable, such as a towed marine contro...

AI Technical Summary

Problems solved by technology

However, ocean electromagnetic field data without measuring any magnetic field components are incomplete, which is not conducive to detailed understanding and analysis of the seabed geological structure and electrical characteristics of the reservoir

In addition, the electrodes distributed along the direction of the cable are not evenly distributed, the electrode density on the cable near the collection ship is higher, while the electrodes on the cable far away from the collection ship are very sparsely distributed

In addition, this towed marine controllable source electric field data acquisition system can only collect electric field data in the time domain or the frequency domain of a single frequency point

[0005] The third is that the ocean electromagnetic data acquisition cable sinks to the bottom, and the excitation source is towed. There is no practical application at present. For example, the patent application with the publication number "CN102472829A" discloses a submarine electromagnetic cable data acquisition system. The cable (EM OBC-ElectroMagnetic Ocean Bottom Cable) is first laid on the seabed by the cable-laying ship, and then the source ship drags the underwater controllable power supply forward at a certain distance from the seabed and supplies power to the seawater (the launch can control electromagnetic wave), the electromagnetic data of the seabed is collected by the electromagnetic cable laid in advance on the seabed

This type of sinking collection 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 marine electromagnetic data collection survey lines or three-dimensional survey networks on the seabed.

In addition, when the collection station is released, it sinks freely without fixed-point release accuracy control. When it is recovered, the marine electromagnetic collection station is brought to the sea by glass floats. The construction efficiency is low, and the failure of the acoustic or mechanical release device causes the collection station and The counterweight cement block cannot be separated, resulting in the failure of the collection station to recover and loss

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