The Study And Application Of Finite Element Method In DC Resistivity Prospecting

With the deepening level of prospecting, the shallow mineral easy to find and use has been dwindling, so the study for the methods of quick prediction location to search for deep non-ferrous metal deposits has become one of the most important topics in the entire geological community today. In the mineral exploration and hydro- geological and environmental geology survey, DC resistivity method is an effective and widely applied geophysical method.In recent years, DC resistivity method has been expanding constantly in the application field, with its observation space from surface to underground and underwater. DC resistivity method has developed in the direction of high-density and high-precision. At the same time, Topography of the area for exploration becomes more and more complex, which also puts forward to new requirements to data processing and interpretation of DC resistivity method.However, for a long time, the earth resistivity anomaly under the condition of rolling topography is a problem in electrical prospecting, which results from the complicated problem itself for one thing and the backward technological development in the same period for another thing. Among numerical simulation methods, finite element method is applied to research because of these advantages such as high precision, a fairly standard problem-solving process, satisfying the internal boundary conditions automatically, suitable for the physical distribution issues of complex terrain, and so on.Starting from finite element simulation of two-dimensional electric media for point source, this paper introduces the theory of two-dimensional finite element method for point source in section, selection of boundary conditions, cell triangulation, interpolation and unit synthesis of finite element method, and simulated calculation using high-density measurement on surface and well resistivity measurement to two-dimensional geoelectric model. Besides, data mapping has been done with data analysed qualitatively and quantitatively.This paper studys futher the resistivity profile anomaly under the undulating terrain, simulates forward resistivity profiles of a variety of typical geoelectric models and analyses the calculated results. And then it is summarized that the regularities of distribution about the resistivity profile anomaly under the undulating terrain, with the false anomaly eliminated successfully.Finally,the paper shows summarily that it is effective to research the resistivity profile anomaly with finite element method in terms of overcoming the effect of the complicated undulating terrain.