1-D Forward And Inversion For Singlecomponent Of Electromagnetic Fieldon CSAMT

Controlled Source audio-frequency Magnetotelluric sounding method (CSAMT) hasbeen proposedby Professor D.W.S trangway and his graduate student Myron Goldtein fromthe university of Torontofor the first time in1971, the CSAMT method provides effectivetechnical means for detectingthe underground electrical structure of tens of meters to2kmdepth,and ithas obtained good geological effectin petroleum, geothermal, solid mineral,hydrology, and other fields.CSAMT single component data collection was raised recentlywithconsidering the apparent resistivity error of the public track data and inconvenience oftrack arrangement, and current mainly concentrated in the Ex.So there is an urgent need for aresearch about single component of CSAMT electromagnetic(EM) field1-D ForwardModeling And OCCAM Inversion, providing theoretical basis for the development of singlecomponent CSAMT measuring and using for reference。There are related research and discussion aboutsingle component of CSAMT EMfield1-D forward and OCCAM inversion in this paper.Based on the basic theory of the EMfield, some formulations of EM fields generated by a dipole source with Lorentz and Fouriertransform from Maxwell equation are deduced. Some significative results are acquired bydesigned a homo-half-space models.Then by increasing a sandwich in homo-half-space tobuild three layers geoelectric model，to simulate the geoelectric model with the differentresistivity、thickness、buried depth of sandwich, Theanalysis results of each components ofelectromagnetic field response show that：the capability to low resistance sandwich is betterthan it to high resistance sandwich, and the capability has enhanced by increasing thethickness and decreasing the buried depth of sandwich; the capability of electric field x、ycomponents toresistivity、thickness、buried depth of sandwich are better than it of componentsof magnetic field.In addition, this paper has discussed the influence of different initial model andselectionof frequencies and distance of receiver from transceiver to the inversionon the basis ofOCCAM1-D inversion basic theory, the results show that: the effect of initial model onOCCAM inversion is little impact;in actual production practice,even fewer frequencies can beselected to achieve the desired effect while selecting the appropriate frequency to correspond to the shallow and deep geological bodies when combining with geological information; theselection of distance of receiver from transceivershould be meet the measurement area islocated infar-field region, and the method should appropriately increase the distance fordetection of deep geological information.The article also constructed a series of typicalone-dimensional layered model to compare the inversion results of singlecomponent ofCSAMT EM filed and simulation of scalar, vector, tensor measurement, the result showsthat:there is no obvious improvement in the multi-component of EM field inversion andsingle component of EM field inversion...