The effect of salinity variation of saline aquifer energy storage rejnjection solution on water-beraing medium permeability

Based on the results of site survey and unified the existing condition,one-dimensional sand column infiltration system with constant flow fluid supply had been constructed.Through the salinity abrupt and gradual tests of rejnjection solution,and double electric layer theory,the main reason of the variation of aquifer medium permeability and space structure in the course of energy storage in saline aquifer was explored.The results showed that the salinity variation of reinjection solution made the releasing,migration and sedimentation produced by clay particle in aquifer medium,which eventually lead to the permeability change in relative short time.The more variation in salinity and degressive gradient of rejnjection solution was,the greater releasing of clay particle and permeability coefficient increased,In the reinjection 100% deionization solution abrupt experiment,the clay particle content in effluent liquid was up to 8.6 g/L and the relative permeability coefficient decreased by 53.8%.meanwhile,the clay particle content was only up to 3.7 g/L and the relative permeability coefficient decreased by 28% in the gradual experiment.