Method Study Of Marine Magnetotelluric Data Processing

Marine magnetotelluric method is a very effective method of geophysical exploration, the field source is a natural electromagnetic waves, the device is relatively simple, relatively easy construction in marine conditions, the vertical resolution is higher than Gravity, aeromagnetic survey, From high impedance shielding, reflecting the sensitivity of low resistivity layer, the probing depth can reach the underground crust and upper mantle, the use of marine MT technology can get the information of the seabed formation resistivity, drilling exploration success rate has been widely applied to marine deep construct exploration, offshore oil and gas and mineral resources exploration and evaluation. Therefore, many methods and techniques of the electromagnetic method, marine magnetotelluric the preferred methods and techniques.Compared with the land, the marine environment which the biggest feature is the high conductivity of seawater on the electromagnetic field attenuation. In addition, the theory suggests that the seawater Games induction electromagnetic field. This induction field is bound to affect the subsequent processing and interpretation of results. The complexity of the ocean marine magnetotelluric exploration easily affected by noise, If you do not eliminate these confounding factors, these will certainly affect the data analysis and interpretation accuracy.Firstly, research the background of the seafloor electromagnetic, current development status of the principle of detection, and data processing methods. Secondly, Analysis marine MT signal characteristics, The impact of sea water on electromagnetic signals, and marine magnetotelluric exploration of noise analysis, summarizes the type of noise source, characteristics, and comparative analysis of different magnetotelluric and marine magnetotelluric noise, Put forward marine magnetotelluric data processing, using median filter and wavelet filter to suppress noise, aimed at raising the quality of the original information and data for later inversion and interpretation of high quality data.Instrument in the delivery process may be affected by the ups and downs of currents and underwater topography, which led to the instrument sensor to deviate from the measurements in the positive direction after reaching the seafloor, This will send the data distortion, Based on the graphics geometric transformation, This article using the azimuth correction of marine magnetotelluric data, And make use of Maxwell theory, the vibration correction data. Detail the basis for the graphics geometric transformation,2D and3D graphics geometric transformation theory, Write a program orientation correction to the simulated data, The corrected time series before and after comparison of the waveforms show that the effective realization of the position correction.The noise of the ocean measurement data, the two filtering methods selected, including one of the traditional median filtering and wavelet filtering method. Median filter has the advantages of nonlinear filtering, good inhibition for pulse noise, Wavelet filtering has superior multi-resolution adaptive, using the sym wavelet the superiority of the optional sym4wavelet processing noise. For the results of the median filter and wavelet filtering, error analysis, Both methods can effectively remove the noise. Sounding curve after the filter denoising improved to a certain extent, significantly increased the seafloor magnetotelluric data quality, That these two methods are more suitable for marine magnetotelluric data processing. These data analysis and processing method to obtain high-quality data and subsequent interpretation accuracy has laid a solid foundation.