Study On The High Precision Method Of Electromagnetic Frequency Spectrum Based On Logging Data

The magnetotelluric sounding method has the characteristics of deep exploration,but the study of its resolution is one of the important directions.Magnetotelluric sounding method for the detection of thin layer geological bodies has been one of the key contents.The standard of thin layer resolution can be established by analyzing it,and the resolution and response characteristics of the thin layer are clarified and recognized.In the actual work,the thickness of target reservoir is different,and its thickness and depth distribution is of great significance for the efficient exploration and development of minerals.The core is to improve the resolution of the exploration,to accurately divide the strata,and to establish the quantitative identification and evaluation method.By numerical simulation of high resistance and low resistance model,the influence of frequency,depth,thickness,transverse conductance,longitudinal conductance and resistivity values on the resolution of thin layer can be obtained.In the low resistivity thin-layer model,longitudinal conductance has the greatest influence on the apparent resistivity curve.In the high resistivity thin layer model,the depth and the thickness have the greatest influence on the apparent resistivity curve.The apparent resistivity formula of magnetotelluric sounding method is analyzed theoretically.It can be assumed that the depth and frequency have linear relationship to obtain the method basis of high precision electromagnetic spectrum technology.Combined with the measured data of the work area,the formula of frequency depth conversion and the establishment of regional geophysical model are obtained after calibration and depth correction based on log data.The analysis and interpretation of the high precision electromagnetic spectrum technology for the data of area is completed,and the similarities and differences of the inversion results are analyzed by combining the magnetotelluric sounding method.High precision electromagnetic spectrum data processing interpretation results of target strata is obviously higher than that of magnetotelluric sounding method,it can divide three sedimentary cycle.The magnetotelluric sounding method has obvious effect on the characteristics of the regional general stratigraphy.