Medium characteristics and hydrodynamic evolution law of high salinity mine water recharge in deep well

The treatment and discharge of high salt mine water is one of the important factors affecting efficient coal mining in recent years. It is a worth exploring method to reduce the discharge of mine water by selecting the appropriate aquifer under the floor of the coal seam and transferring the high salt mine water to other places. Taking the X mine in the Ordos Basin as an example, the Baotashan sandstone and the deep Liujiagou Formation sandstone formation below the coal seam have transfer storage space. By mercury intrusion experiment and rock mechanics analysis, the two groups of formations were analyzed for medium characteristics; the water level natural recovery test, water pressure test and numerical simulation were used to study the hydrogeological parameters and hydrodynamic field. The research results show that Baotashan sandstone has a porosity of 6.57%-19.89%, which has great water storage potential but is too close to the mining coal seam. The transfer and storage of mine water may cause the threat of water inrush from the floor, so the current mining stage is not considered as a transfer storage layer. The permeability of Liujiagou Formation is 4.18%-7.49% and the permeability coefficient is 5.31×10^-6 m/d in the original state. After water injection and fracturing, the hydrogeological parameters of the Liujiagou Formation are 0.008 14-0.015 27 m/d. The permeability is greatly improved and can be maintained in a stable state. MODFLOW numerical simulation results show that the Liujiagou Formation has a good prospect in the long-term transfer and storage of mine water.