| As the four major oil storage and transportation bases in China,Zhoushan has about 150 oil depots with a capacity of about 25 million cubic meters.It is easy to cause oil spill due to improper handling or accidents during the process of petroleum storage,transportation,refining,etc.Effective monitoring and control of the oil depot has become an urgent problem to be solved.Therefore,this paper takes the soil around Zhoushan coastal oil depot as research object,and studies the relationship between soil oil content and resistivity by resistivity method.Since the coastal soil of Zhoushan belongs to saline soil,the corrosion resistance of detection electrode will be severely tested when in-situ detection is performed by resistivity method.Firstly,the corrosion resistance of electrode is improved by preparing a superhydrophobic super-lipophilic copper electrode,so as to achieve long-term and stable monitoring effect.Secondly,a mathematical model between soil petroleum pollutant content and resistivity applicable to the surrounding oil reservoirs in Zhoushan was established,and this mathematical model will be evaluated.Finally,an on-line in-situ detection system between soil resistivity and oil content is proposed to support the monitoring of actual soil oil contamination level in the next step.In order to improve the corrosion resistance of detection electrode,the surface of electrode is modified in this paper.Immersing the copper electrode in mixed ethanol solution of silver nitrate and myristic acid,the superhydrophobic copper electrode can be prepared by self-assembly of myristic acid on the surface of silver particle in only 10 minutes.The results of corrosion resistance test by electrochemical workstation show that the surface contact angle of prepared superhydrophobic copper electrode can reach 154.9°,at the same time,its corrosion performance is favorable,and the corrosion inhibition efficiency in corrosive media can reach 83.9%,which greatly improves its corrosion resistance.In order to achieve the on-line in-situ monitoring of petroleum-contaminated soils,this paper uses resistivity method to simulate the experiment of petroleum pollution soil resistivity,to study on the effects of water saturation,oil saturation,porosity and other factors on the resistivity of petroleum-contaminated soil and discussed the response relationship between oil-contaminated soil parameters and resistivity under different conditions.The results show that soil resistivity is greatly affected by initial water content of the soil.By introducing the oil saturation to improve the Archie type formula and re-fitting the data between resistivity of petroleum contaminated soil and pollutant content,it is found that the trend between calculated value and measured value is closer.The relationship between the both sides is ??=42.82??0.46,and the relationship between oil saturation and soil resistivity is ??2=247Swo-1.059.By verifying validity and practicability of the obtained oil saturation and soil resistivity formulas,it is found that the actual value of soil oil content is close to the value of oil content which calculated by resistivity method.The minimum relative error of this both sides is 0.75%,the maximum value is 9%,the average value is 5.43%,and the detection accuracy can reach about 95%.The correctness of this model has been confirmed,and it can basically meet the accuracy requirements of production practice.Therefore,the model between soil resistivity and oil content obtained in this experiment can be applied in the surrounding area of Zhoushan Oil Depot.In order to solve the problem of rapid evaluation of contaminated and uncontaminated areas during resistivity monitoring,this paper developed a simple device based on electrical resistance method to detect soil oil pollution.Based on this detection device,the upper detection limit of oil content in soil can reach 0.77%,It is able to quickly identify which areas have been contaminated by oil using the resistivity method. |
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