Study On Seepage Law Of Horizontal And Vertical Well Combined Mining In Deep Sandstone Uranium Reservoir

With the rapid development of nuclear power construction,the demand gap of uranium resources in today's society is huge,and improving the efficiency and output of uranium resources is an important issue to be solved urgently.Among the uranium resources in China,sandstone uranium ore accounts for the largest proportion.Among them,the shallow mineral resources are exhausted,and marching to the earth's deep has become the main goal.In situ leaching method is generally adopted for mining,which has the advantages of short construction period,low production cost,high resource utilization rate and good safety,and has become the main mining method for sandstone-type uranium deposits in ChinaIn order to improve the efficiency of in-situ leaching mining,this paper adopts the method of combining laboratory experiment and numerical simulation to optimize the layout of horizontal and vertical Wells.By collecting the hydrogeological data in the study area,the pressure drop of horizontal well is tested and verified by simulation.The orthogonal test was used to reduce the number of tests.The well spacing and pumping ratio were selected as the influencing factors,and the orthogonal test was carried out at three levels.Through the establishment of the horizontal well site model in the study area,the groundwater level of the in-situ leaching well site was simulated,and the groundwater level distribution map under different schemes was obtained.The groundwater solute transport model was established by using the groundwater flow field in the mining area studied.The migration and diffusion law of the leaching solution in the ore-bearing aquifer was predicted by using the simulation software.The orientation of horizontal well,the spacing between horizontal well and vertical well,and the ratio of liquid injection and pumping volume in horizontal well pattern are optimized.This research can provide some theoretical and technical guidance for insitu leaching of uranium ore.The main conclusions are as follows:(1)The pressure drop seepage test and simulation verification of horizontal well show that the laboratory test results are in good agreement with the numerical simulation results.In the model,the pressure is stable with almost no pressure drop within a distance of 0?9.6 m,and the pressure drop of horizontal well can be ignored in the GMS simulation.(2)Under the combined action of hydrodynamics of natural underground flow field,pumping well and injection well,the water level of in-situ leaching well site rises near the horizontal injection well,forming a high pressure area.In the vicinity of the pumping well,the water level falls,forming a falling funnel,and the liquid around the pumping well flows to the well.Under the action of the surrounding head pressure,the groundwater level of the wellsite reaches the balance in a short time.The closer the water flow velocity is to the pumping well,the faster the water flow velocity is.(3)Through the analysis of the migration distance and diffusion range of the leaching solution in different schemes,it can be seen that scheme 8 is the best,that is,the distance between the pumping well is 60 m,the distance between the injection well and the pumping well is 45 m,and the pumping ratio is 3:2,the diffusion range of the leaching solution is the widest.