Analysis And Research Of Marine Electromagnetic Transmitters And Receivers

In mineral exploration of seabed resources, marine electromagnetic method is avery important and effective way. It uses a control factory source as the excitationsource, surveying the seabed electromagnetic field value, to compensate for the lackof low-frequency signals in the ocean marine environment, through the calculation ofapparent resistively and phase, combined with the communication distance, or thedirect use of the electric field observed the purpose of underground electricaldistribution and magnetic field reached the detectable size. Marine electromagneticmethod in addition to the outside of the earthquake, the study of marine, in particular,the seabed is an important geophysical methods, with probing depth range, destructive,implementing a simple, adaptable and accurate detection features, its as a risk controlmeasures to help the exploration staff to identify potential oil and gas reservoirs, andprovide the basis for the exploration to drilling decisions.In the launcher, can affect the emission signal of the factors have a lot of thisarticle Maxwell electromagnetic equations combination of theoretical basis, theanalysis such as send and receive from the transmit signal waveform, and transmit thesignal frequency, the apparent resistively, depending on the phase as well as launchingantenna, etc.probe. Generally determine the frequency range of the transmitted signalis0.01-50Hz.In the receiving device, submarine receiver able to receive the signal, there arethree: the first is the direct wave signal, the second is from the seabed strata ofreflection and refraction of electromagnetic signals, and the third is the reflection fromthe surface of the water and refraction of electromagnetic signals. Electromagneticreflection waves in the seabed through the distance will be very long, so under normalcircumstances than the direct wave signal is weak. Electromagnetic refraction of the vertical high-impedance reservoir of the incident wave energy although theattenuation in the high-impedance reservoir, but the more the signal will betransmitted along the high impedance level, and its energy will continue to reflectionto the bottom receiver arrangement, when the transceiver from the high resistancereservoir depth or greater than the depth position of the electromagnetic signalreturned by the high resistively layer energy will exceed the direct wave energy todominate, and generally determine the size of the transceiver from the reservoir depth2-5times for the best. The receiving antenna to the circuit theoretical knowledge asthe basis for analysis of the emission current induced voltage Ramp pulse, an inducedvoltage curve. The antenna is divided into the transmitting antenna and receivingantenna. Usually two as a combination used in submarine detection, usually selectedcombination is the combination of a central loop and horizontal electric dipole.This article is based on729projects, of Chengdu University of Technology isresponsible for the National Marine Airborne geophysical exploration and applicationof projects completed as the basis. The main work has focused on the analysis of theprinciple and the parameters of transmitters and receivers, the theoretical basis for thesubsequent practical feasibility.