Research On The Effect Of Temperature On The Performance Of Electrochemical Geophone And Compensation Method

Seismic exploration is a common method to get the information of the earth's internal structure.With the increasing depth of exploration,the seismic geophone should have excellent low frequency signal detection ability.The electrochemical geophone developed based on molecular-electronic induction technology is a new type of geophone,which has been widely used in the field of low frequency signal detection in recent years.The electrochemical geophone uses liquid electrolyte as the inertial mass body.Under the excitation of the external vibration signal,the electrolyte inside the reaction chamber flows due to the inertia effect,which leads to the change of the ion concentration distribution around the sensitive core electrode,and then causes the change of the output current,the external vibration signal can be detected by measuring the output current.Compared with the traditional electromechanical geophone,it has the advantages of small size,high sensitivity,strong impact resistance,low frequency characteristics and so on.However,in practical applications,the working temperature of the electrochemical geophone is limited by the boiling point and freezing point of the electrolyte inside the reaction chamber,the solution viscosity and the ion diffusion coefficient change exponentially with the temperature.When the ambient temperature changes greatly,the performance parameters of the electrochemical geophone will change,which will affect the reliability of the collected data quality.The study of the regularity of the output characteristic of the electrochemical geophone with the temperature change is of great reference value for the practical application of the electrochemical geophone.In this paper,the influence of temperature change on the performance of the electrochemical geophone is studied through a combination of simulation and experiment.The main research contents include the following aspects:(1)According to the structure and working principle of the electrochemical geophone,a multiphysics theoretical model of the sensitive core was established.Based on this,a simulation model of the sensitive core of the electrochemical geophone was established using COMSOL Multiphysics simulation software.The effect of temperature change on the output sensitivity of the electrochemical geophone was studied by simulation analysis.(2)In order to measure the temperature characteristic of the electrochemical geophone,it is necessary to change the working environment temperature of the electrochemical geophone and achieve constant temperature control.According to the actual testing requirements,a small temperature control system with temperature control function is designed.The system can achieve a temperature control range of 7 ~ 60 ?,and the temperature control accuracy can reach ± 0.3 ?.(3)The temperature characteristic of the electrochemical geophone is measured by using the ultra-low frequency vibration calibration system of Jilin University and the temperature control system designed.The sensitivity temperature characteristic curve of the electrochemical geophone was given and which was compared with the traditional moving coil geophone temperature characteristic.The effect of temperature on the sensitivity and amplitude-frequency characteristic of the electrochemical geophone was analyzed through experimental data.The temperature drift model of the electrochemical geophone was established based on the experimental data,and the temperature compensation formula for the output sensitivity was given.The sensitivity drift of the measured electrochemical geophone is obviously reduced after applying the compensation formula to correct the data,the maximum rate of sensitivity change is not more than 7% at different temperatures.