Research On The Physical Scale Modeling Of Horizontal Layered Model Of Borehole-surface Electromagnetic Method In Frequency Domain

Electrical exploration plays an important role in exploration geophysics,it is a common exploration method for geophysical resources and engineering exploration.Borehole-surface electromagnetic detection technology is an important detection technology in electric exploration.With the rapid development of science,technology and theoretical knowledge,borehole electromagnetic method has been widely used in field production activities.Electromagnetic method in the field construction of exploration Wells,often place high power transmitter on the ground,and place the vertical bipolar source in the well,make the anomaly target source closer to the body,the transmitter by vertical bipolar source emission of a specific frequency square wave signals,and lay on the ground line to collect electromagnetic response,by studying the collected data to the inversion of underground electrical structure,understanding of underground formation types.This way of working has an advantage over ground electromagnetic detection,because the transmitting source is closer to the target body,which makes the receiving signal more efficient and the data more accurate.To electromagnetic method in this paper,the author studies on well the physical simulation experiment,it is according to the principle of similarity criterion,the real wild environment of geometrical and electrical parameters,using the appropriate author made experimental model,and through the hole to experiment to simulate the electromagnetic detection technology,based on the experimental model of abnormal responses of the collection,observation and discussion,indirectly,by the object of study.Based on the previous model research,this experiment mainly explores the electromagnetic response differences between the high-resistance model and the low-resistance model,as well as the isotropic model and the horizontal layered model,and obtains the electromagnetic response laws of different models.At the same time,Comsol Multiphysics software was used to conduct 3d borehole and ground electromagnetic numerical simulation modeling,and the results of physical simulation and numerical simulation were compared to verify the correctness of physical simulation and numerical simulation.It provides preliminary experimental results for the development of three-dimensional anisotropic forward inversion theory of borehole electromagnetic method.Based on the research of three-dimensional anisotropy inversion and physical simulation of well-ground electromagnetic method in the frequency domain and the surface project of national natural science foundation of China,the physical simulation and three-dimensional numerical simulation of horizontal layered model of well-ground electromagnetic method are carried out based on the previous research results.Through in-depth research on the experimental scheme,the selection of experimental model materials,the production of models,the collection,processing and interpretation of experimental data,the following results were obtained:1)Using the one dimension numerical simulation of high and low resistance of abnormal body and isotropic model and simulate a horizontal layered medium model,different models were obtained through the calculation of the electromagnetic response law of one-dimensional numerical simulation results analysis discussion,for the well to provide train of thought of physical simulation of electromagnetic and validate the results of physical simulation data.2)In a one-dimensional numerical simulation results under the guidance of the theory,follow the basic theory of similarity criterion,combined with the field construction parameters and laboratory conditions,select the experimental material,the production of abnormal body model and simulation Wells in the laboratory to electromagnetic field construction process,through the physical simulation experiment for abnormal high resistance,low resistance anomalies and horizontal layered medium model body and the isotropic model body laboratory ground electromagnetic response data.3)Using Comsol Multiphysics software to calculate the ground electromagnetic response of four 3d models forward,and from the perspective of numerical simulation,the electromagnetic response differences of borehole and ground electromagnetic method for high and low resistivity anomalous bodies,horizontal layered medium model and homogeneous model are analyzed.By comparing the experimental data of physical simulation and the experimental data of numerical simulation,the discriminative response of borehole electromagnetic method to the strata with different electrical structures is explained theoretically and practically,which provides an important help for the three-dimensional anisotropy inversion of borehole electromagnetic method.