Zoning and Modeling of the Underground Hydrosphere of the Orenburg Region

The Orenburg region is located in the south of the Russian Federation, on the border with Kazakhstan, within the Southern Urals and the southeastern part of the Russian Platform. The sedimentary cover contains groundwater of varying chemical composition. Vertical zoning allows for hydrogeological zoning of the territory under consideration. The purpose of the study is to construct a model of the hydrosphere and hydrogeological zoning of the Orenburg region and adjacent territories. Research methods include mapping and zoning of the territory based on routine observations of the quality of natural waters and sources of pollution. As a result of the study, it was established that surface and groundwater in the field area have a varied chemical composition, depending on both natural and anthropogenic factors. Eight vertical hydrogeological zones are identified on the platform. The model of the hydrosphere with its hydrodynamic levels is presented as follows: (1) the upper level with local and regional underground flow; (2) the lower floor of the sedimentary cover and water-pressure system with regional aquifers and good conditions for the preservation of hydrocarbon deposits; (3) a floor of gravitational fractured waters up to the Conrad boundary, the movement of fluids, blocks and plates is geodynamic in nature; (4) the level of waters in a supercritical state from the Konrad border to 900 km.