Research And Application Of Gravity Data Processing Methods

As the material basis for the development of industry and agriculture in modern society,mineral resources are the necessary conditions for ensuring that people live a modern life.Therefore,the exploration of mineral resources is an indispensable link in the development of the national economy and in the modernization drive.Geophysical prospecting is a kind of exploration technology that studies the structure of the Earth's interior through physical principle and method,which is an important method to carry out prospecting of mineral resources.Among them,gravity exploration,with the advantages of low cost,large exploration depth,wide application coverage and high efficiency,is an important branch of geophysical exploration methods.The processing of gravity data is an indispensable link in gravity exploration.Its purpose is to extract valid information from the measured data and obtain valuable geological information by performing field separation,boundary identification and gravity inversion.In this thesis,the methods of gravity data processing such as analytical continuation,Butterworth filtering,derivative calculation,Euler deconvolution,and 3D inversion of gravity data are studied.The main research contents and achievements are follows:1.This thesis introduces the methods of upward continuation and Butterworth filtering,and carries out the related research.The theoretical model experiment is designed to compare the accuracy of the two methods for field separation.The result shows that the field separation result of Butterworth filtering method is better.2.This thesis introduces six kinds of boundary identification methods including vertical derivative,total horizontal derivative,total gradient module,oblique derivative,total derivative of oblique derivative and Theta map.Three sets of theoretical model experiments are designed to compare the boundary recognition effect.The results show that each of the six kinds of boundary recognition methods has its advantages and disadvantages.In the actual data processing work,a variety of boundary identification methods should be used for comprehensive analysis in orderto obtain more accurate geological body boundary information.3.This thesis introduces the rapid inversion method of Euler deconvolution and studies its construction index selection.Three sets of theoretical model experiments are designed to test its accuracy in the boundary identification.The results show that the Euler inversion can roughly delineate the scope of the model body.The center position sets a good correspondence,but there are some slight deviations at the border.4.This thesis introduces the theory of gravity three-dimensional inversion.Two sets of theoretical model experiments are designed to test the accuracy of the inversion results.The results show that in the absence of a priori conditions,the inversion results of shallow anomalies are better and the inversion results of deep abnormal body are not ideal.5.The gravity data processing method is used to process the measured gravity data,which delineates three low-density granite bodies.And the result is in good agreement with the actual geologic data,which provides a reference value for future gravity data processing.