The System Realization Of CSAMT Data Inversion Explanation

In recent years, due to the rapid development of CSAMT at home and abroad in searching geothermal field, oil, coal field and solid mineral etc and its better geologic effect, quite a lot CSAMT instruments are imported, But the data interpretation software is hard to support the instrument well. So, it needs badly to develop a necessary interpretation and simple inversion software for the instrument imported.In order to support the GTP-32Ⅱinstrument of College of Geoexploration Science and technology, A CSAMT(or MT) data processing and 1-D inversion software is developed in this paper and at the same time build a data processing and inversion interpreting system, offer a platform for users to interpret the CSAMT (or MT) data quickly. Following points are completed in this article: (1). Edit of field data; (2).Dealing with the static effects of curve using spatial filter; (3). Smooth disposing of abnormity point by interactive program; (4). Correction of the near-field data; (5). Triangle method correction of the transition middle-field data;(6). 1-D inversion; (7). Build CSAMT data processing and inversion interpretation system.There are many methods for CSAMT(or MT) static correction, but some are influenced much by artificial factors, So in this paper we use spatial 1-D filter to do static correction. The reason why we take spatial filter as basic start point for static correction is that we think the apparent resistivity variety which is slow and gradual along the survey line , but caused by partly electric property non-homogeneous media in the ground surface or the local undulate terrain is rapid and sharp .The spatial 1-D filter is low pass filter and it can suppress the static effect of high frequency as long as filtering along the survey line.In the data–display and editing soft, field data will be shown as apparent resistivity graph automatically and abnormal point of obviously mutation can be edited and modification artificially. In the near field and middle field data correction method and soft , the data of nor-far-zone will be amended to far-zone. And this provide advantage for the CSAMT supporting inversion soft which is applicable for the far-zone data.Simulated annealing(SA) is important branch of calculating using natural low, which analogies combinatorial optimization problems andthermal balance in statistical mechanics problems and open up a new way to solve combinatorial optimization problems. It is different from linear and iterative inversion method, and don't much depend on the initial model. In this method, the optimization process of target function is regard as lowering the temperature annealing process. SA, which includes the thinking of joining uniform distribution demand that the test points location of each iteration in the solution space must meet Cauchy distribution, and this markedly improved. the efficiency of CSAMT 1-D inversion.The field data of CSAMT (or MT) will become the fixed format data files required by the 2-D inversion by using the steps of data processing described above and then the 2-D inversion could be on, so the efficiency of data processing is improved greatly.