Application Research Of Magnetotelluric Sounding Method In Oil And Gas Exploration In The Xuefeng Area Of ??Jiangnan

Have excellent primary oil and gas geological conditions and a number of high-quality oil and gas reservoir strata in China Shanxi Xuefeng side area has good exploration prospects,but because of its harsh natural environment,complex geological conditions,resulting in the use of conventional oil and gas prospecting method is limited.The high impedance carbonate formation blocks the downward penetration of seismic elastic wave and greatly influences the effect of seismic prospecting.The magnetotelluric sounding method uses natural alternating electromagnetic field as a field source,without artificial source,suitable for mountainous areas;at the same time,the magnetotelluric sounding method to detect electromagnetic signals of different frequency,the detection depth is only related to the frequency of the electromagnetic field,so the method has advantages of strong penetration ability,not affected by the high resistivity layer,the exploration depth of the.So,the magnetotelluric sounding method can be applied to complex terrain and surface conditions of seismic exploration very difficult to work in the mountains,through the analysis of magnetotelluric sounding data,can infer faults and structural traps,stratigraphic division of the main interface and facies,can provide important basis for the evaluation of oil and gas exploration area.Therefore,it is of great significance to study the application of MT in oil and gas evaluation.On the basis of Sinopec South exploration company "Jiangnan Xuefeng tectonic belt of magnetotelluric regional survey data processing and interpretation" project,selected two magnetotelluric profiles in Shanxi Xuefeng side,processing and interpretation of data.This paper from the basic theory of magnetotelluric,introduces the working method and technique of magnetotelluric method,using a variety of methods for processing and inversion of magnetotelluric data,combined with geological and geophysical survey of Shanxi area on the side of the Xuefeng,magnetotelluric profiles for interpretation,finally got the two oil and gas area,and get the following conclusion:The phase data of magnetotelluric and apparent resistivity data are not independent of each other,and the phase information by electromagnetic interference is relatively small,so in this study,to restore the apparent resistivity data is distorted by the quality of the phase data better,and achieved good results.In the same tectonic unit,Apparent Resistivity Frequency Magnetotelluric curve of the same or similar,the similar points in the first resistivity weighted average,static correction of magnetotelluric data with the same tectonic unit,the measuring point clustering static correction method,the method to eliminate static and reserved the point mutation caused by the change of geological structure,effective information will not be lost.Bostic,one-dimensional continuous media inversion,two-dimensional imaging inversion,gradient inversion,uneven inversion,and other methods are used for inversion.The characteristics of Bostick is unique,the basic characteristics of obtaining formation of electric section;one-dimensional inversion provides the corresponding relationship between the depth and resistivity of higher resolution,and the use of one-dimensional inversion results provide initial model for the 2D inversion;finally through the implementation of 2D inversion of stratum structure and electrical characteristic,using gradient method and the residual method to classify fault,get the final magnetotelluric inversion profile.Combined with the geological,physical and other oil and gas data in the previous survey area,the section map is compiled,and the favorable oil and gas remote scenic spots are deduced.