Research On The Characteristics Of Seismoelectric Effect Of Porous Rock Samples Under Different Fluid Media

Due to its special karst landform,mine water disasters occur frequently in Guizhou Province.At the same time,due to the particularity of mine working environment,once large-scale water gushing occurs,it will cause a large number of casualties and huge economic losses.In order to effectively prevent and control mine water disasters,the seismoelectric exploration technology in the field of physical logging is introduced into the field of mine water prevention and control.In this paper,a series of seismoelectric effect experiments are designed and carried out by means of indoor experiments,aiming at the characteristics of mine rocks and groundwater in Guizhou karst area,and the results are as follows:(1)A whole set of measurement system for detecting seismoelectric signals in the laboratory was built,and the key points for measuring seismoelectric signals in the laboratory were found,and the measurement system was optimized and improved.The results show that obvious seismoelectric signals can still be measured in the laboratory without laying shielding nets or building shielding rooms.The whole seismoelectric signal measurement system should be well grounded,especially the reference potential of the negative pole of the amplifier should be consistent with the ground potential at the electrode;All factors in the seismoelectric measurement system will affect the acquisition of seismoelectric signals.(2)The seismoelectric effect of argillaceous dolomite,dolomitic limestone and red sandstone is verified,and the difference of seismoelectric response between carbonate rock and red sandstone is explored.The results show that argillaceous dolomite can produce obvious seismoelectric signals under the excitation of acoustic waves,and the characteristics of the signals are consistent with those of red sandstone,while dolomitic limestone does not produce obvious seismoelectric signals because of its low porosity The seismoelectric signal measuring system built in this paper can effectively collect seismoelectric signals.(3)By collecting the seismoelectric signals of argillaceous dolomite in different kinds of solutions and different concentrations,the seismoelectric response characteristics of argillaceous dolomite in different solutions are obtained.The results show that the amount of water in the flume basically has no effect on the seismoelectric effect of rocks;With the increase of solution concentration(salinity),the intensity of seismoelectric signal gradually decreases.When the solution concentration increases to0.05mol/L,the seismoelectric signal is extremely weak,and when it increases to0.08mol/L or above,the amplitude of seismoelectric signal is basically zero.(4)The seismoelectric response characteristics of argillaceous dolomite under different water saturation degrees are studied.The results show that rock samples can produce seismoelectric signals even when they are not fully saturated with water.With the decrease of water saturation,the seismoelectric signals drop sharply.When the water saturation drops to 50%,the seismoelectric signals are weak.When the water saturation drops to 40% or below,the amplitude of seismoelectric signals is basically zero.(5)The seismoelectric effect of argillaceous dolomite in mine groundwater is verified.The results show that rock samples can generate seismoelectric signals in groundwater,and the higher the salinity of groundwater,the worse the coupling effect of seismoelectricity and the smaller the amplitude of seismoelectric signals.In this paper,the seismoelectric response of carbonate rocks in different fluid media is taken as the research object,combining theory with practice,in order to open up a new research road in the field of mine water prevention and control in karst areas and make some contributions to the development of seismoelectric effect.