The Study Of Several Potential Field Imaging Methods And Apply In Geothermal Prospecting In Songjianghe

The processing and interpretation of potential field data is an important branch of geophysical exploration methods.Gravity and magnetic prospecting in potential field data have the advantages of simple theory,easy data acquisition,low work cost and high lateral resolution.They have important applications in structural division and geological body boundary recognition.The potential field itself is derived from the physical property(density or magnetic susceptibility)of the underground geological body.It is difficult to improve the vertical resolution in the inversion of potential data due to the fact of that the geological field is difficult to separate when the potential field is stacked together.The determination of the depth of anomalous field source is a problem that needs to be solved in potential field inversion.The 3D inversion method used before is often complicated,requiring a priori model,or the result is not accurate.In this paper,several new methods for determining the depth of geological bodies are studied.They are potential field imaging methods.The specific research contents are as follows:1.Study the basic theory of the three imaging methods,carry out the model test and verify the feasibility and reliability of the three methods.2.The improved DEXP imaging method,the ratio DEXP imaging was introduced,it was compared with the original method by model test.The imaging ability was improved by model test,but the effect of deep abnormal imaging was not ideal.3.The migration imaging based on window data is proposed.This method can improve the imaging accuracy and introduce the migration imaging based on gradient data.Through the model test,it is found that the two improvements can improve the imaging accuracy.The gradient based migration imaging can improve the lateral resolution.4.The correlation imaging method based on window data and gradient data is introduced.Through the model test,it is found that the two kinds of these two kinds of improvements can enhance the imaging precision and improve the lateral resolution.5.Comparative analysis of the imaging capabilities and application conditions of the three methods and their improved methods.6.The gravity data of a certain area in the Songjiang River area is separated and identified,the structure in the region is divided,and the appropriate local anomalies are selected to prepare the subsequent treatment.7.In the local anomaly,the depth information of the anomalous field source is obtained by using a variety of imaging methods to intercept the data of the outburst anomaly,and the possible location of the geothermal resources is deduced with the structural division.