Research On Complex Resistivity Measurement And Frequency Spectrum Curve Of Nature Rock

In recent years,the application scope of Geophysics has been expanding with the exploitation of shallow mineral resources and the development of infrastructure projects in China,and the reliability requirements of geophysical exploration have become increasingly high.Induced polarization method directly utilizes the difference of IP effect between rocks and ores and is applied in many aspects of geophysical exploration.At the same time,in other geophysical electrical methods,considering IP effect can also improve the accuracy of result interpretation.Therefore,it is necessary to study the IP effect of rocks and ores in depth.Firstly,on the basis of collecting relevant data,this paper summarizes twelve kinds of complex resistivity models which are used to describe the IP effect of rock and ore.Then,forward modeling is carried out in Cole-Cole model,Dias model,Generalized Cole-Cole model and Multi-Cole-Cole model.By changing the values of different parameters in the model,the change of corresponding spectrum curve is observed.After that,157 samples of different kinds of natural rocks and ores from different regions were collected and classified according to different lithologies.The sweep frequency measurements in the range of 10^-2-10³Hz were carried out by using Portable SIP Field/Lab Unit spectrum IP instrument,and the corresponding amplitude spectrum and phase spectrum were obtained,which were analyzed and studied.Based on the above work,this paper analyses and summarizes the influence of different parameters in four complex resistivity models on their spectral curves,and found that different parameters in the complex resistivity model have different effects on the amplitude and phase curves,and the amplitude and phase curves of the complex resistivity are the comprehensive embodiment of all parameters in the model.Generally speaking,the amplitude of different types of rock and ore decreases with the increase of measurement frequency.The amplitude curve of rock generally changes less at low frequency and more at high frequency,which is just the opposite of the amplitude curve of some metal ores.The phase of all rocks and ores is negative in the measuring range.The complex resistivity of rock and ore samples is affected by many factors,such as structure,structure,composition and degree of breakage.