Research On The Migration And Transformation Of Polyacrylamide In The Soil Of Daqing Area

Polyacrylamide(PAM),as the main component of polymer flooding in tertiary oil recovery technology,will pollute the soil during oil exploitation and development,causing increasingly serious damage and damage to the ecological environment.This paper studies the variation of vertical migration of PAM in soil by constructing a physical model of indoor soil column.Soil column watering experiments are carried out to investigate the effects of PAM irrigation concentration,PAM irrigation amount,time and soil type on the vertical migration of PAM in soil and the vertical migration of PAM in soil under ASP solution.The effects of PAM irrigation concentration,PAM irrigation amount,rainfall,soil type and other factors on the vertical migration of PAM in soil under simulated rainfall conditions and the vertical migration of PAM in soil under ASP solution conditions are investigated by soil column leaching experiments.The degradation of PAM in soil is analyzed by designing degradation experiments at different times,initial PAM content and anaerobic conditions.Under natural conditions,the PAM content in the soil decrease gradually with the deepening of the migration depth,and the largest decrease occurres in the soil at1~4 cm.Under the same PAM concentration,the less the amount of watering,the less the PAM content in the same soil layer,the smaller the migration distance in the soil,but the water content is not linear with the PAM content in the soil.After 5 to 10 days of watering,the effect of PAM on soil migration is not negligible.Under the same conditions,the content and migration distance of PAM in saline-alkali soil is smaller than that of chernozem.Under the same conditions,the ASP solution is reduced in the amount of 2 cm before the surface layer of the soil and the content of several centimeters increase in the ASP solution compared with the single PAM.Under simulated rainfall conditions,the lower the initial concentration of PAM in the soil under the same PAM volume,the greater the maximum distance of vertical migration.The vertical migration distance of PAM is enhanced with the increase of watering amount.Compared with natural conditions,the PAM content in the soil surface layer is reduced and the migration distance is deepened.The longer the simulated rainfall time,the greater the rainfall,the greater the amount of PAM migration in the soil with water,and the higher the PAM content in the deep soil.Under the same conditions,the content and migration distance of PAM in chernozemare larger than that of saline-alkali soil.Compared with the ASP solution under natural conditions,the migration depth of PAM in the ASP solution in the soil is further deepened,and the content of PAM in the soil surface layer is reduced.The natural degradation rate of PAM in soil increases during 0~50 days,but the overall degradation rate is not more than 3%.The degradation rate is the highest in20~30 days,and the degradation rate slows down after 30 days.At the same treatment time,the lower the initial content of PAM,the higher the degradation rate.With the increase of time in 0~40 days,the degradation rate of PAM under aerobic conditions gradually increase,and the PAM in the soil can be degraded to the maximum extent within the period of 16~24 days.The degradation rate of PAM in the anaerobic state is minimal.