The Migration Simulation Of Radon In Drilling

In the process of drilling sandstone-type uranium deposits,the original closed environment is destroyed,and the radioactive gas of radon in the ore-seam position continuously,which leads to the displacement of the radioactivity balance of radium radon.Gamma ray logging is mainly derived from the decay progeny of radon,the equilibrium state of radium radon is observed by geophysical parameter hole,and the ratio of initial total irradiation rate to the last relative stable total radiation rate is taken as the equilibrium coefficient of radium radon.Schematic diagram of geophysical exploration parameters Establishing geological models to provide data foundation and data comparison.This paper mainly analyses the amount of radon produced in the ore seams in the unit time.Based on the migration mechanism of radon by diffusion convection,a geological-physical model and mathematical model of radon migration in homogeneous medium under unsteady conditions are established,and the unsteady two-dimensional migration equation of radon under closed environment is deduced.The concentration distribution of radon in strata is obtained by solving the equation by finite volume method.The concentration distribution of three-dimensional plane and the distribution of radon in different time periods are obtained by the two geological model maps.1)by numerical simulation,we can get the distribution map of radon concentration change over time with different pressure,and the higher the pressure,the greater the radon balance displacement,the more upward drift.2)by comparing the measured data with the theoretical model,we can see that the position of radon in the upper and lower diffusion displacement is very limited,only for 20-30 cm.This may be directly related to the porosity of the upper and lower strata.Radon migration is mainly reflected in the horizontal direction of the changes.With the increase of the distance between radon source and drilling,the velocity of radon migration becomes smaller.When the concentration of radon is evenly distributed on the x-y plane,the concentration distribution of radon in the x-z plane is high and the concentration is low.Overall upward migration is larger than the following migration distribution.