Application Research Of Three-dimensional Numerical Simulation Of Airborne Transient Electromagnetic Method

With the increasing maturity of airborne transient electromagnetic method,it has been widely used in mineral resources exploration,groundwater exploration,marine and military fields.This paper mainly makes people understand the abnormal response characteristics and abnormal distribution law of 3D airborne transient electromagnetic,and combined the national key research and development plan of "Deep Resource Exploration and Mining" project "A typical coverage area airborne geophysical technology demonstration and processing interpretation software platform development" major project "Airborne Transient Electromagnetic The research on data processing methods and software development of law and terrestrial electrical methods",for this reason,the vector finite element algorithm is used to carry out three-dimensional forward modeling of airborne transient electromagnetic,Through the simulation of a large number of geological models and the calculation of different electrical parameters,the effects of helicopter flight altitude,low-resistance overlay thickness and cover resistivity on airborne transient electromagnetic data are discussed,and electromagnetic anomalies are analyzed.Response characteristics and abnormal distribution rules.Firstly,based on Maxwell's equations,one-dimensional and three-dimensional electromagnetic field expression formulas of aeronautical transient electromagnetic method are derived.In the three-dimensional finite element forward modeling,the frequency domain electromagnetic response formula is first derived,and then the cosine variation is used to convert the electromagnetic field.The cubic spline interpolation function converts the time domain electric field to the decay voltage.In order to verify the accuracy of the airborne transient electromagnetic three-dimensional finite element algorithm,a typical three-dimensional layered model such as H,K and HAK is simulated,and then compared with the one-dimensional digital solution curve,and the relative error is calculated.The relative error of the Z component is basically within 3%,which verifies the feasibility of the proposed algorithm.Then three-dimensional forward modeling of single block,multiple block,inclined plate and other models in uniform half space is carried out.On this basis,the helicopter flight height,low resistance cover thickness,cover resistivity,etc.3D numerical simulation of changes in model parameters.By analyzing the Z-component multi-channel curve,the attenuation voltage curve,and the global apparent resistivity profile and curve,the scope of the target,the location of the space,the occurrence and the anomaly of the model aviation transient electromagnetic method are analyzed and discussed.relationship.Finally,based on the actual geological data,the geoelectric model of the water-rich goaf of a coal mine in Yangquan,Shanxi Province was established.The three-dimensional numerical model was carried out and its anomalous characteristics were analyzed.This study provides a theoretical basis for the actual measurement of airborne transient electromagnetic data interpretation,and has certain reference value for the three-dimensional inversion of airborne transient electromagnetic method.