The Research And Application Of IP Intermediate Gradient Inversion And Imaging On Undulate Topography

For a long time, geoelectric anomalies are always a problem in electrical prospecting study on undulate topography. On one hand,the problem itself is complex, on the other hand, the level of technological development in different time can not reach the point to completely solve the problem,such as the three-dimensional problem, even with a good theoretical basis, if the computer can not keep up the computing speed and the memory is not enough, but also can not achieve the desired results. Today, the development of the computer is sufficient to meet the computing speed, accuracy requirements, it provide opportunities to solve the complex geophysical issues.In the current environment, the direct current 2-D and 2.5D inversion method is widely used. The three-dimensional inversion technology is still not mature, although there are also applications, but due to the precision and speed of calculation is far from the two-dimensional technology, making the development of the three-dimensional inversion has been suppressed. Therefore, in order to develop three-dimensional inversion, it is necessary to improve the accuracy and speed of calculate. As a starting point, we should find a new method of calculation.So far, the research and applications of equivalent source in gravity and magnetic potential field transformation have achieved good results. This thesis learn the superiority in the development and application of gravity and magnetic fields, considering the electrical prospecting in time domain induced polarization in gradient observations, when the power supply electrodes are far enough, and the measuring electrodes are in the heart of the two current electrodes, the electric field can be regarded as uniform field. It contents the premise that using the equivalent source to process and research. In the second period of The Computing Techniques for Geophysical and Geochemical Exploration in 2015, we discussed the results of the equivalent source inversion imaging in the time domain IP intermediate gradient. The effect of the study is obvious, and it is also achieved good effects in the actual data processing. In order to give full play to the advantages of the equivalent source, this article will continue to further study of the application of the equivalent source in the IP intermediate gradient on undulate topography. On the one hand in order to correct for the influence of the terrain, on the other hand in any terrain conditions direct inversion interpretation.This paper from the IP intermediate gradient abnormal of the spherical polarizable body, began to study the topography influence on apparent polarization value. We designed a series of different three-dimensional model, and then calculate the model’s polarization values in undulating terrain conditions. And arrangements(design) a series of model(sphere) imaginary field sources(equivalent source) in the space, according to the principle of least squares, solving the equivalent sources in the field and the actual observation plane(corresponding to the model theory here is an exception) to achieve the best fit of the charge amount, then the amount of charge is determined according to the size, distribution body size field source, spatial location and shape. By comparing the calculated results, a preliminary understanding of the impact of topography on the apparent polarization. And then using the equivalent source method to do three-dimensional imaging, looking for effective calculation method to decrease the topography’s influence on apparent polarization, reduce abnormal distortion. And to the actual production provide a more secure and convenient new data processing methods.The research focuses on the topography influence on polarizability, and affects the amount of charge. In this paper, the terrain is added to the IP intermediate gradient data processing, which is the innovation of this article. The subject of research has a certain significance and value, in the future, we will use IP intermediate gradient more precisely look for minerals, underground water resources and etc.