Study On Optimization Of Groundwater Monitoring Network For Petroleum Hydrocarbon Pollution Site Based On Natural Attenuation Process Simulation

Oil and gas exploration,exploitation,smelting and petroleum processing products in transportation and use of links will inevitably cause a certain degree of pollution to the surrounding environment.The optimization of groundwater pollution monitoring well pattern can obtain more site pollution information,and optimize the number of monitoring Wells,so as to reduce monitoring cost and improve monitoring efficiency.Therefore,this paper takes petroleum hydrocarbon pollutants as the research object,uses TVOC software to simulate the natural attenuation process of petroleum hydrocarbon pollutants in groundwater,and analyzes the influence of natural attenuation on the concentration distribution of petroleum hydrocarbon pollutants in groundwater and the spatial distribution law of petroleum hydrocarbon pollutants in groundwater.Monte-Carlo method was used to analyze the uncertainty of the numerical simulation model and evaluate the reliability of the numerical simulation model.Finally,the simulation optimization method is used to establish the optimization equation with the goal of maximizing the monitoring information,and the implicit enumeration method is used to solve the point location of the groundwater pollution monitoring network.The main conclusions are as follows:(1)Natural attenuation effect of the volatile,dissolve and adsorption in the field of groundwater is relatively small,the influence of petroleum hydrocarbon pollutants concentration distribution and biodegradation can make petroleum hydrocarbon pollutants in the groundwater is decreased obviously,therefore,in the process of petroleum hydrocarbons pollution monitoring network simulation of the consideration of natural attenuation action can improve the accuracy and effectiveness of the network.(2)The distribution of water-bearing media in groundwater is heterogeneous,and the single value of hydrogeological parameters often cannot reflect the heterogeneity of media,which affects the accurate characterization of the spatial distribution characteristics of pollutants in the migration simulation of petroleum hydrocarbon pollutants in groundwater.In this paper,monte-carlo simulation is used to calculate the mean value of concentration distribution data of petroleum hydrocarbon pollutants for monitoring well pattern optimization under the condition that the porosity and permeability parameters fluctuate in a certain range of 1000 groups.Compared with the simulation results using a single hydrogeological parameter value,the mean pollutant concentration can better reflect the distribution of petroleum hydrocarbon pollutant concentration in the ground water of the site.(3)In this paper,an optimization scheme of groundwater monitoring network based on the concentration zoning of petroleum hydrocarbon pollutants is proposed,which can monitor the high concentration distribution area of petroleum hydrocarbon pollutants and the spatial distribution of pollutant concentration.It is proved that the pollution information of the optimized monitoring network is higher than that of other well layout schemes when the number of monitoring Wells is the same,which indicates that the monitoring network optimization method based on natural attenuation process simulation is effective and can be applied to more petroleum hydrocarbon contaminated sites.