Research On Rapid Simulation And Data Processing Of Semi-aerial Transient Electromagnetic

Compared with the ground transient electromagnetic method,semi-airborne transient electromagnetic method has high exploration efficiency;compared with aeronautical electromagnetic,its signal to noise ratio and spatial resolution have a good advantage.Although the advantages of semi-aerospace electromagnetic method is obvious,but the development of difficult.So,it is very slow in the practical application of the development.In the development process of the semi-airborne transient electromagnetic method,its instrument design and development is critical.Similarly,data processing and interpretation is also very important.This paper is based on 1D forward and inversion of SATEM: first,producing 1D forward analog signal and dealing with the noise signal;then,using the verified method to process the measured data;at last,inverse imaging of measured data.The details of the work are described as follows.The paper discusses some pre-stack processing methods for semi-airborne transient electromagnetic data.First,the attenuation characteristics of electromagnetic signal is analyzed,and then describes the effect of the digital loop filter in suppressing periodic noise;at last,this paper focuses on the characteristics of aperiodic noise and the repression noise methods in electromagnetic signals.The thesis researches on semi-airborne transient electromagnetic inversion imaging.First,this paper analyzes the 1D forward modeling of SATEM,the forward modeling is realized by analyzing the electromagnetic field excited by the long ground wire,analyzing the uniform half space and the Three-layer model;secondly,the "binary value" problem in the depth-of-conductance imaging is solved by establishing the look-up table,and then the apparent depth is transformed into the imaging depth by the apparent depth formula to obtain the results of the depth imaging of the conductivity;at last,the basic principle of regularization inversion algorithm is analyzed,the inversion model of the three-layer model is realized.The paper accomplishes some work about processing and analysis of semi-airborne transient electromagnetic measured data.First,according to the actual work of the field,the prepare work need to carry out,including detection of measurement data and determine of the secondary field;next,the symmetric rejection stack,the area-defined rejection selective stack and slope-based selective region suppression of three selective stack methods are used to eliminate sporadic noise in time domain;furthermore,for the profile data after selective stack,which can be eliminate noise in the space domain by the FIR and SR two post-stack filtering methods,it can be effectively eliminate the “burr” on the profile curve;finally,the data of LOTEM and the conductance depth imaging results of SATEM are compared and analyzed.