Improve The Method Of Transient Electromagnetic Exploration Resolution Based On The All Time Apparent Resistivity

The exploitation and utilization of coal resources，a n established state policy，has been playing an important part in the development of our national economy．However，hydro geological conditions in the Chinese coal mines are extremely complicated and flooding occurs constantly， which threatens safe production and has caused huge losses and serious consequences. Therefore, the prevention and control of coal mine flooding remains a big problem to be tackled．To carry out the transient electromagnetic method (TEM), hydro geological additional exploration and advanced prediction is an effective way to solve the problems of Mine Water. However, the result of TEM detection is not so satisfactory in some of the complex geological conditions, and to improve its resolution is an urgent need, in order to meet the needs of production safety. The article introduced the basic concept of resolution, all time apparent resistivity can be computed by using(Hz)．M eanwhile， the calculation of inverse function have been finished by binary-search．Finally，the inversion based on smoking rings theory and genetic inverse method have been realized. Then based on the layered formation model，we conducted experiments of qualitative and quantitative interpretation for the thin layer. Finally, the two instances, respectively, verify the effect of off-time correction and inversion methods to improve the resolution, and compare the advantages and disadvantages of smoke ring inversion and genetic algorithm.On the basis of the above work, many results have achieved. In this paper, the region of apparent resistivity is used for study the approach to improve the transient electromagnetic prospecting resolution, and the region apparent resistivity data has been taken full advantage of to overcome limitations of the early or late apparent resistivity. The programs which use multiplexing of the Simpson formula values to calculate the probability integral and take the dichotomy solving nonlinear inverse function, is prepared. We verify that the all time apparent based on the magnetic field strength is only a single value and more accurate than that based on the induced electromotive force. The programs of the "smoke ring" recursive inversion and the genetic inversion algorithm based on Elitist Selection, which are both calculated by all time apparent resistivity, is prepared. By the TEM numerical simulation of thin layer in the layered model, we explain that the position of thin layer reflects more accurately than the thickness in TEM. The article also pointed out that within the detection range, the depth and thickness ratio of the most conducive to the quantitative interpretation is10︰1. By experiments, it summarizes the different effects on the resolution of transient electromagnetic prospecting, when the parameters and the correction of off-time problem is different. Comparing the effect of the smoke ring inversion with that of the genetic algorithm, the resolutions both have improved to achieve the desired effect, and are able to solve practical problems, but the latter is better for getting layers.